tourism and recreation coral reefs

Healthy coral reefs are good for tourism – and tourism can be good for reefs

Image:  The Nature Conservancy/Ami Vitale

.chakra .wef-1c7l3mo{-webkit-transition:all 0.15s ease-out;transition:all 0.15s ease-out;cursor:pointer;-webkit-text-decoration:none;text-decoration:none;outline:none;color:inherit;}.chakra .wef-1c7l3mo:hover,.chakra .wef-1c7l3mo[data-hover]{-webkit-text-decoration:underline;text-decoration:underline;}.chakra .wef-1c7l3mo:focus,.chakra .wef-1c7l3mo[data-focus]{box-shadow:0 0 0 3px rgba(168,203,251,0.5);} Robert Brumbaugh

.chakra .wef-9dduvl{margin-top:16px;margin-bottom:16px;line-height:1.388;font-size:1.25rem;}@media screen and (min-width:56.5rem){.chakra .wef-9dduvl{font-size:1.125rem;}} Explore and monitor how .chakra .wef-15eoq1r{margin-top:16px;margin-bottom:16px;line-height:1.388;font-size:1.25rem;color:#F7DB5E;}@media screen and (min-width:56.5rem){.chakra .wef-15eoq1r{font-size:1.125rem;}} Future of the Environment is affecting economies, industries and global issues

.chakra .wef-1nk5u5d{margin-top:16px;margin-bottom:16px;line-height:1.388;color:#2846F8;font-size:1.25rem;}@media screen and (min-width:56.5rem){.chakra .wef-1nk5u5d{font-size:1.125rem;}} Get involved with our crowdsourced digital platform to deliver impact at scale

Stay up to date:, future of the environment.

Tourism is one of the world’s largest industries, contributing trillions of dollars to the global economy and supporting the livelihoods of an estimated one in ten people worldwide.

Much of that tourism depends on the natural world—on beautiful landscapes and seascapes that visitors flock to in search of escape, a second wind, and a direct connection with nature itself.

Coastal and marine tourism represents a significant share of the industry and is an important component of the growing, sustainable Blue Economy, supporting more than 6.5 million jobs—second only to industrial fishing. With anticipated global growth rates of more than 3.5%, coastal and marine tourism is projected to be the largest value-adding segment of the ocean economy by 2030, at 26%.

That nature is the foundation for much of the world’s tourism is clear—travelers are willing to pay a premium for a room with a view, and words like “pristine,” “remote,” and “unspoiled” are frequently assigned to amenities like beaches, coral reefs, and panoramic seascapes. The dependency of the travel and tourism industry on a healthy environment goes much deeper than that, however. Not only does a reef provide entertainment value for seaside visitors, but it can deflect waves that cause erosion and reduce the risk of storm surges that can harm the industry’s bottom line.

Furthermore, mangroves and seagrass meadows are excellent at absorbing and storing carbon, reducing harmful emissions that cause climate change. And all of those coastal ecosystems produce fish that are a favourite on restaurant menus, providing additional economic opportunity for coastal communities.

Clearly, nature contributes enormous value to tourism and other industries. But one of the challenges is knowing exactly where these benefits are produced in the first place. This knowledge can enable smarter investments in management and conservation actions that support both nature and the tourism businesses that support coastal economies.

The Nature Conservancy’s Mapping Ocean Wealth (MOW) initiative provides exactly this information. A new MOW study published in the Journal of Marine Policy reveals that 70 million trips are supported by the world’s coral reefs each year, making these reefs a powerful engine for tourism.

In total, coral reefs represent an astonishing $36 billion a year in economic value to the world. Of that $36 billion, $19 billion represents actual “on-reef” tourism like diving, snorkeling, glass-bottom boating and wildlife watching on reefs themselves. The other $16 billion comes from “reef-adjacent” tourism, which encompasses everything from enjoying beautiful views and beaches, to local seafood, paddle-boarding and other activities that are afforded by the sheltering effect of adjacent reefs. The impact of this new information is already being recognized, as Mapping Ocean Wealth received the 2017 Tourism for Tomorrow Innovation Award from the World Travel and Tourism Council.

In fact, there are more than 70 countries and territories across the world that have million dollar reefs—reefs that generate more than one million dollars per square kilometer. These reefs support businesses and people in the Florida Keys, Bahamas, Mexico, Indonesia, Australia, and Mauritius, to name a few.

This knowledge matters—not just for the tourism industry, but for conservation, too. The old adage goes, ‘you can’t manage what you can’t measure.’ Armed with concrete information about the value of these important natural assets, the tourism industry can start to make more informed decisions about the management and conservation of the reefs they depend on—and thus become powerful allies in the conservation movement.

We’re starting to see great examples of businesses that are investing directly in the health of reefs that they know support their business enterprises. For more than 10 years, the Misool Eco Resort in Indonesia has worked with local communities and invested in creating and managing a no-take marine protected area encompassing 828 square kilometers in Raja Ampat, a spectacularly biodiverse area within Indonesia’s West Papua province. Within this protected area, fish abundance and size has increased dramatically, with benefits for the coral reefs that surround the nearby islands.

Half-way around the world, Fury Watersports in Key West, Florida, donates a portion of each snorkel-trip fare to coral restoration, helping to support the recovery of several species of endangered and threatened corals that provide habitat for all kinds of marine life within the Florida Keys National Marine Sanctuary.

Both of these businesses understand their dependence on reefs and are making direct investments in these natural amenities. It’s a win-win for the tourism economy and nature.

The Conservancy’s Atlas of Ocean Wealth , and accompanying interactive mapping tool , serves as a valuable resource for managers and decision makers to drill down to determine not just the location of coral reefs or other important natural assets, but how much they’re worth, in terms of their economic value as well as fish production, carbon storage and coastal protection values. By revealing where benefits are produced and at what level, the MOW maps and tools can help businesses fully understand and make new investments in protecting the natural systems that underpin their businesses.

The concept of valuing nature isn’t a new one, but the detailed, targeted knowledge of the MOW initiative presents an opportunity for the travel and tourism industry to lead both in the private sector, institutionalizing the value of nature into business practices and corporate sustainability investments, and in the sustainability movement more broadly by capturing the business opportunities that exist when we realize that we need nature.

For more information visit nature.org/coralreeftourism

Don't miss any update on this topic

Create a free account and access your personalized content collection with our latest publications and analyses.

License and Republishing

World Economic Forum articles may be republished in accordance with the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Public License, and in accordance with our Terms of Use.

The views expressed in this article are those of the author alone and not the World Economic Forum.

Related topics:

The agenda .chakra .wef-n7bacu{margin-top:16px;margin-bottom:16px;line-height:1.388;font-weight:400;} weekly.

A weekly update of the most important issues driving the global agenda

.chakra .wef-1dtnjt5{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-flex-wrap:wrap;-ms-flex-wrap:wrap;flex-wrap:wrap;} More on Nature and Biodiversity .chakra .wef-17xejub{-webkit-flex:1;-ms-flex:1;flex:1;justify-self:stretch;-webkit-align-self:stretch;-ms-flex-item-align:stretch;align-self:stretch;} .chakra .wef-nr1rr4{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;white-space:normal;vertical-align:middle;text-transform:uppercase;font-size:0.75rem;border-radius:0.25rem;font-weight:700;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;line-height:1.2;-webkit-letter-spacing:1.25px;-moz-letter-spacing:1.25px;-ms-letter-spacing:1.25px;letter-spacing:1.25px;background:none;padding:0px;color:#B3B3B3;-webkit-box-decoration-break:clone;box-decoration-break:clone;-webkit-box-decoration-break:clone;}@media screen and (min-width:37.5rem){.chakra .wef-nr1rr4{font-size:0.875rem;}}@media screen and (min-width:56.5rem){.chakra .wef-nr1rr4{font-size:1rem;}} See all

How nature positive start-ups are helping China build a carbon neutral economy

Yangjie (JoJo) Zheng and John Dutton

June 26, 2024

The world has a water pollution problem. Here’s how innovation can help solve it

Tania Strauss and Sundararajan Mahalingam

How can offshore wind be a nature-positive climate solution?

Xi Xie and Qin Haiyan

June 24, 2024

AMNC24: What to know about climate, nature and energy

Spencer Feingold

June 23, 2024

4 steps to jumpstart your mangrove investment journey

Whitney Johnston and Estelle Winkleman

June 20, 2024

Richer nations divided over climate crisis funding for poor countries, and other nature and climate stories you need to read this week

Michael Purton

June 19, 2024

MIT Science Policy Review

Coral reefs are critical for our food supply, tourism, and ocean health. We can protect them from climate change

Hanny E. Rivera * , Andrea N. Chan, and Victoria Luu

Edited by Alexandra Churikova and Anthony Tabet

Full Report | Aug. 20, 2020

* Email: [email protected]

DOI: 10.38105/spr.7vn798jnsk

• Coral reefs provide ecosystem services worth $11 trillion dollars annually by protecting coasts, sustaining fisheries, generating tourism, and creating jobs across the tropics.
• Ocean warming is the most widespread and immediate threat to coral reefs globally, followed by disease, and local stressors.
• Management efforts help address local stressors, however, the root cause of global coral decline – increasing temperatures caused by greenhouse gas emissions – must be addressed to ensure the survival of the ocean’s most diverse habitats through the 21st century.
• International climate agreements that aim to continually reduce emissions are our best hope for the survival of reefs.

Article Summary

As many as 1 billion people across the planet depend on coral reefs for food, coastal protection, cultural practices,and income [1, 2]. Corals, the animals that create these immensely biodiverse habitats, are particularly vulnerable to climate change and inadequately protected. Increasing ocean temperatures leave corals starved as they lose their primary source of food: the photosynthetic algae that live within their tissue. Ocean warming has been impacting coral reefs around the globe for decades, with the latest 2014-2016 heat stress event affecting more than 75% of the world’s corals [3, 4]. Here, we discuss the benefits humans derive from healthy reefs, the threats corals face,and review current policies and management efforts. We also identify management and policy gaps in preserving coral habitats. The gain and urgency of protecting coral reefs is evident from their vast economic and ecological value. Management and restoration efforts are growing across the globe, and many of these have been influential in mitigating local stressors to reefs such as overfishing, nutrient inputs,and water quality. However, the current trajectory of ocean temperatures requires sweeping global efforts to reduce greenhouse gas emissions in order to effectively safeguard the future of coral reefs. The U.S. should stand as a world leader in addressing climate change and in preserving one of the planet’s most valuable ecosystems.

Coral reefs are one of our planet’s most biodiverse and economically valuable ecosystems [5], yet they have been declining worldwide due to warming ocean temperatures and other stressors [6]. Many major tropical cities are adjacent to coral reef environments (Figure 1A), with nearly 1 billion people worldwide residing in areas influenced or sustained by coral reefs [1, 2]. Coral reefs provide a myriad of ecosystem services that benefit our economies, our shorelines, as well as our plates and medicine cabinets (Figure 2). Throughout, we discuss the valuable benefits provided by corals, explain the stressors harming coral reef ecosystems across global and local scales, review management and conservation efforts, and identify gaps in current policies.

Why corals matter: A wealth of ecosystem services

Coral reefs are dynamic, vibrant ecosystems, formed by over 800 different species of corals. Corals are animals, closely related to anemones and jellyfish, although considering them rocks or plants would not be entirely off base. Their tripartite nature stems from their ability to create the limestone skeleton in which they live, and from the single-celled algae (marine plants) that live inside their tissues in a mutualistic symbiosis (Figure 3A). These algae provide corals with the vast majority of their energetic needs, by providing sugars they produce via photosynthesis to their coral hosts. In addition, corals also harbor a diverse bacterial flora that contributes to their overall health [7], much like the gut microbiome does in humans [8]. These associations allow corals to thrive and build reefs large enough to be seen from space, such as the Great Barrier Reef or the Florida Reef Tract (Figure 1B, 1C).

Coastal Protection: These massive reefs structures can function as seawalls against storms, hurricanes, and sea level rise by protecting coasts from waves and surge [9]. In fact, coral reefs provide the equivalent of $\$$94 million in coastal protection to the U.S. each year [10]. During severe storms, like category 5 hurricanes, that value increases to $\$$272 billion [10]. Worldwide, the total value of coastal protection provided by reefs is estimated at over $\$$4 billion in averted damages during usual storms [10]. For more extreme events such as one-in-25-year or one-in-a-100-year level storms, corals can prevent $\$$36 billion to $\$$130 billion dollars’ worth of damages, respectively [10]. For comparison, the Port of Miami and Port Everglades (Ft. Lauderdale, FL) collectively represent over 3% of all U.S. seaport trade and are worth over $\$$50 billion dollars each year; while the Miami International Airport comprises over 5% of U.S. airport trade, worth nearly $\$$60 billion per year [11]. Corals can provide equivalent amounts of value during mild storms and much more value during severe storms. Coastal protection by coral reefs not only benefits immediately adjacent cities and residents, but can also prevent downstream economic impacts to trade and commerce. In addition, the presence of coral reefs is often used to define maritime boundaries and jurisdictions (see section on UN Convention on the Law of the Sea), such that deterioration and loss of coral reef habitat can lead to loss of jurisdiction over marine territories. 

Biodiversity and Natural Products: The reef structures created by corals provide habitat for thousands of marine species, in a manner that is highly disproportionate to their total area. While comprising only a small fraction of seafloor (0.2%) [12], coral reefs are home to an estimated 830,000 species of organisms [13]. The number of species living per unit area on coral reefs is one of the highest on the planet, with biodiversity that rivals rainforests. 

This biodiversity is crucial for the health our oceans, and it can also be harnessed for natural product and drug development. For instance, the antiviral drug Vira-A, which is used to treat herpes simplex infections, as well as AZT, which is used to treat HIV, were derived from a compound (Ara-A) isolated from a Caribbean sponge that lives on coral reefs [14]. Another compound (Ara-C) was isolated from the same sponge and developed into the anti-cancer medication Cytarabine [14]. The drug Ziconotide for the treatment of chronic pain was isolated from cone snails found on coral reefs [15]. In addition, several new antibiotic compounds effective against antibiotic-resistance bacteria have been isolated from soft corals that live in coral reefs [16]. The skeletons of hard corals can even be used as bone regeneration materials for humans [17] Overall, the oceans represent a highly unexplored source of products for human medicine. The drug discovery potential in marine environments, and coral reefs in particular, should be considered an invaluable resource [18, 19]. 

Fisheries and Tourism: The biodiversity of corals reefs also includes fish and seafood species that form part of a 143 billion dollar global fisheries trade industry, such as groupers, lobsters, and snappers [20]. In the U.S., recreational fisheries on coral reefs are worth over $\$$100 million each year. In addition, nearly half of all U.S. fisheries depend on healthy coral reefs ecosystems for sustainable stocks [21]. Excessive fishing on reefs can cause considerable damage and threaten the stability of the ecosystem (see fishing pressure section below). As such, coral reef fisheries benefit from strong management plans that limit the risk of overfishing important species. 

Coral reefs also form the foundation of many tourism industries in coastal areas across the globe. In Australia, the Great Barrier Reef received over 26 million visitors in 2016, and tourism to the Queensaland area generates around $\$$6.4 billion (AUD) annually [22]. In the U.S., reef-based tourism in the states of Hawai’i and Florida alone are estimated at over $\$$2 billion dollars annually [23]; and at nearly $\$$240 million in Puerto Rico [21]. ¹

¹Values adjusted for 2020 dollars from the 2007 values reported in [21]

Figure 2: Coral reef ecosystem services (blue) and threats (red). Reefs offer valuable services to humans. Unfortunately, corals are impacted by multiple threats, many of which act to compound each other. Image was created on biorender.com. Icon credits to Lluisa Iborra (skyline), Ifki Rianto (small fishing boat and fisherman), Ruliani (wave), Nikita Kozin (diver), and Luis Prado (large fishing boats), all available from The Noun Project. Reef and associated fish are original artwork by author H.E.R.

What’s killing all the corals: Global and local threats to reefs  

Despite their vast ecological, economical, and pharmaceutical importance, coral reefs are one of the planet’s most rapidly degrading ecosystems [6]. On a global scale, corals are most severely impacted by increasing temperatures, coral diseases, and declining pH levels. At regional and local scales, stressors such as overfishing, run-off from land, and coastal development lead to coral mortality and reef degradation [24]. We discuss the causes, effects, and prevalence of different stressors below. While we have organized this section into global and local stressors, reefs are complex ecosystems and are often subjected to multiple stressors simultaneously. It should also be noted that this is not a comprehensive list. For instance, we do not discuss light and noise pollution, ship groundings, invasive species, or tourism pressure. We have focused on the stressors that we consider the most pressing to address given the magnitude of their impact.

Global Stressors

Temperature: Corals can suffer severe stress if water temperatures rise by just 1◦C above their usual summer maximum [25]. While this change in temperature may seem trivial at first, consider the impacts of a fever on human health, where only a 1-2◦C increase can quickly become life threatening. At higher temperatures, corals lose the symbiotic algae that live inside their tissues, and which provide the coral with the majority of their daily food requirements [25, 26] (Figure 3A). This process is called ‘bleaching,’ as the symbionts are also the main source of color in coral tissue (Figure 3B). Bleaching is often fatal to the coral animal, as they can starve to death without their symbionts. If temperatures return to normal within a few days or weeks, the coral can re-establish their community of symbionts and may survive; but this time window is becoming more elusive as heat stress events are becoming both more prolonged and more severe [27].

Since the 1980s, episodes of bleaching have reached reefs around the world, and even iconic and well-protected areas, like the Great Barrier Reef have lost up to 50% of their live coral [6]. Such bleaching events have increased in both frequency and intensity over the last two decades, and it is projected that by 2050 almost all reefs will experience bleaching level temperatures on an annual basis [27, 28]. The most recent global bleaching event (between 2014-2016) caused devastation across the globe [3]. For instance, this event caused 100% bleaching and nearly 95% coral mortality on Jarvis Island, a U.S. territory in the central Pacific [29]. This island had previously been rated as the healthiest and most robust coral ecosystem on the planet [30], and lacks any other sources of coral stress, underscoring the pervasive impact climate change can have on even the most remote and pristine ecosystems. The Great Barrier Reef in particular, has continued to experience bleaching events every year since 2014, and is seeing its most widespread bleaching event this year [31]. On a smaller scale, other stressors can also prompt a bleaching response in corals, including cold temperature, pollution, high UV, and pathogens [16]. However, heat-induced mass bleaching remains the primary cause of coral decline on a global scale [4, 28, 32, 33]. These declines emphasize the desperate need to curtail the carbon emissions that are responsible for increasing ocean temperatures. 

Disease: Corals have also been affected by disease outbreaks, especially in the Atlantic/Caribbean, where they have been one of the main sources of decline from the mid 1970’s to today [34]. In the late 1970’s, an outbreak of white band disease decimated the three major Caribbean coral species (Acropora cervicornis, palmata, and prolifera) that were the dominant reef builders in the region [35]. In 2014, a new disease, now called Stony Coral Tissue Loss Disease (SCTLD), began in Miami-Dade County, and has since spread throughout the Caribbean [36]. The disease impacts more species than any other known coral diseases, and also kills corals more quickly [36]. In Florida alone, more than 30% of corals have died from the disease over the last few years [36]. Despite much investigation, scientists have yet to isolate the pathogen that causes the disease. 

Disease prevalence in corals has also been increasing over time and is sometimes exacerbated by increased temperatures [37]. Combined, disease and bleaching are major causes of coral mortality, and both are predicted to worsen as climate change progresses [33, 37]. Diseases can also be triggered by local stressors such as coastal human inputs. For instance, in Guam, prevalence of white syndrome was linked to increased nitrogen from sewage outfalls [38]. In Florida, the outbreak of SCTLD also coincided with the dredging of Port Miami, which led to substantial sedimentation and coral mortality [39] [40]. An overall increase in nutrients has also been linked to higher disease prevalence in the both field and experimental studies [41]. Given these synergies, outbreaks of coral diseases are expected to increase [42]. Management efforts that aim to limit sources of coral disease should be high priority especially in the Atlantic/Caribbean, where they have already caused substantial decline. 

Ocean acidification (declining ocean pH): In addition to warming our planet, carbon dioxide emitted into the atmosphere dissolves into our oceans, triggering chemical reactions that increase the acidity of the water (lower the pH level) [43]. Some studies indicate that pH levels in reef water are declining more rapidly than in the open ocean [44]. At lower pH, the process that corals use to build their skeletons (calcification) and which creates the reef structure requires more energy, meaning coral growth slows and they build less reef [45]. The chemical dissolution of older reef structures, as well as erosion of live corals by live organisms, like encrusting mussels or worms, is also easier at lower pH [46, 47]. 

Ocean acidification also negatively impacts the many shell-building organisms that reside on reefs, such as mussels, clams, urchins, and other calcifying organisms [48]. Even fish growth and metabolism can be impacted under low pH, especially during larval stages [49] In addition, pH often interacts negatively with warmer temperatures, hindering growth and survival of corals [50]. As with mitigating the effects of warming, addressing the root cause – rising CO2 levels – is the best course of action to prevent further damage.

Local Stressors

Coastal Development and Nutrient Enrichment: Coastal development can generate sedimentation from poor-land use practices and new development, or nutrient run-off from agriculture and wastewater discharge. The construction of new resorts may involve overwater bungalows, built directly on reef structures, or the creation of artificial beaches that change coastline dynamics and increase sedimentation to nearby reefs. The expansion of ports to accommodate cruise liners or large container ships, often requires dredging of the surrounding reef flats in smaller tropical islands [51, 52], or even larger cities like Miami [40]. On a more dramatic scale, territorial conflicts in Spratly Islands in the South China Sea, have led to land reclamation techniques by China in which reefs are filled to create land that can be claimed [53]. Such efforts destroyed an estimated 6 square miles (3,000 football fields) of coral reef habitat in 2015 [54]. Coastal development represents a severe a direct physical risk to coral reef survival. The environmental impacts of development projects should be thoroughly assessed by independent parties prior to permitting to help alleviate such pressures. 

Nutrient influx to reefs is primarily driven by human activity. Coastal development, sewage and water treatment effluents, agricultural runoff, and discharges from shipping can all increase nutrient levels on reefs. Macroalgae (different from the microalgae that live inside coral tissues) compete with corals for space on reef environments [55]. Normally, macroalgal growth is limited by nutrient availability, but with an influx of nutrients algae can grow more quickly and begin to grow over the coral [55]. This often results in a shift from a coral-dominated reef to an algal-dominated ecosystem [56] (Figure 3B). These patterns can also be exacerbated if there is overfishing of herbivorous fish, which help keep macroalgal populations in check (see Fishing Pressure).

Algal-dominated habitats quickly begin to lose fish species that relied on corals for shelter [56]. Algae can also trap sediments, leading to negative feedback loops that further stress the remaining corals [57]. Algal-dominated reefs lose their value as protective barriers to shorelines, as dead corals can no longer create additional reef structure. In addition, nitrogen and carbon inputs from land can alter the pH of coastal waters, exacerbating ocean acidification in those areas [58]. Policies that limit the environmental impact of coastal development projects and ensure that coastal infrastructure (e.g. sewage pipes and water treatment plants) is well-maintained can significantly limit continued damage to coral reefs locally.

Fishing Pressure: Corals rely on healthy populations of herbivorous fish and invertebrates to keep macroalgal populations from outcompeting them [59]. Overfishing of herbivores like parrotfish and rabbitfish can result in algal population spikes [60, 61]. In 1990, Bermuda banned pot fishing, a practice that mainly impacted herbivorous fish species. As a result, populations of herbivores rebounded [62]. Other fishing practices like dynamite (also called blast fishing) or cyanide fishing can directly destroy reef habitats and kill coral reef organisms. While these methods are not practiced in the U.S., they still represent a significant threat to reefs in the Indo-Pacific, where many U.S. and international non-profits dedicate efforts to reef conservation. Dynamite and cyanide fishing are often practiced by smaller-scale fishermen, harvesting coral reef fish for the aquarium trade (most of which is sent to U.S.) or direct consumption. In Tanzania, for example, dynamite fishing was outlawed in the 1970s, but has continued essentially unchecked [63]. Cyanide fishing allows for the live capture of fish by temporarily anesthetizing them [64]. The concentrations of cyanide used to target the desired fish, however, can be quickly detrimental to coral reef organisms, such as smaller fish and invertebrates [64]. Efficient enforcement against both these practices in the Indo-Pacific would be a substantial relief to local coral reefs; as would limiting overfishing of herbivorous species across coral habitats.

Figure 3: Overview of coral biology. (A) Coral symbiosis. Corals form massive reef structures made of calcium carbonate (limestone) as their skeleton. The live coral tissue is at the surface of this rock, where colonies of polyps (middle inset) cover the skeleton. Inside the polyps, single-celled algal symbionts (left inset) live in specialized tissues. In addition, a diverse microbial community (right inset) lives on and within corals. (B) Coral bleaching and algal overgrowth. A healthy reef (left) undergoes bleaching due to high temperatures (middle). The coral is unable to recover and dark brown macroalgae now grows over the dead coral skeleton (right) causing a shift from a coral-dominated ecosystem to an algae-dominated one. (C) Coral life cycle. Corals can reproduce sexually to create larvae that then float and swim until finding a new home, where they settle down and attach to the seafloor. Corals can also reproduce asexually via fragmentation, whereby a piece of an adult colony breaks but then reattaches elsewhere on the seafloor and continues growing to form another colony. Photo credits: Coral images in A and B are from the Coral Image Bank (Ocean Agency/Caitlin XL Survey: CC license). Symbiont image in panel A was taken by T. LaJeunesse and is reproduced with permission. Polyp image was taken by author H.E.R. Diagram in panel C is original artwork by Nicola G. Kriefall and is reproduced with permission.

What’s protected: U.S. policies addressing coral reefs  

Reducing human access to reefs can mitigate the impact of local stressors on corals – buying them time to become more tolerant of global stressors [65]. Marine Protected Areas (MPAs) are defined as: “[an] area of the marine environment that has been reserved by federal, state, territorial, tribal, or local laws or regulations to provide lasting protection for part or all of the natural and cultural resources therein” (Executive Order 13158, 2000). MPAs may differ in their level of restrictions depending on the conservation goals surrounding their designation. Two specific classes of MPAs are sanctuaries and monuments. The National Oceanic and Atmospheric Administration (NOAA) and Congress may both designate sanctuaries under the National Marine Sanctuaries Act (16 U.S.C. §§ 1431 et seq., 1972), while the President can establish marine national monuments under the Antiquities Act of 1906 (54 U.S.C. §§ 320301-320303, 1906). A number of MPAs include coral reef habitats within U.S. jurisdiction:

• Papahānaumokuākea National Marine Monument in the Northwestern Hawaiian Islands was established in 2006 and is the largest contiguous marine conservation area under U.S. jurisdiction (Proclamation 8031, 2006). A proclamation by President Obama expanded the monument to cover the entire U.S. exclusive economic zone west of 163 West Longitude, providing greater protection for the region’s coral reefs (Proclamation 9478, 2016). • Pacific Remote Islands Marine National Monument includes Wake, Baker, Howland, and Jarvis Islands, Johnston and Palmyra Atolls, and Kingman Reef. Protecting the high coral diversity and endemic coral species in these areas was a major justification for its establishment (Proclamation 8336, 2009). • Florida Keys National Marine Sanctuary protects the largest coral barrier reef in the United States (15 C.F.R. part 922, subpart P; Pub. L. 101–605, 1990). • Flower Garden Banks National Marine Sanctuary was established to protect the northernmost living coral reefs on the U.S. continental shelf (56 F.R. 63634, 1991). • Marianas Trench Marine National Monument protects one of the most diverse coral ecosystems in the Western Pacific and the deepest part of our world’s ocean (Proclamation 8335, 2009). • National Marine Sanctuary of American Samoa (formerly Fagatele Bay National Marine Sanctuary) was designated in response to a proposal from the government of American Samoa, in part to preserve a pristine coral reef terrace ecosystem (51 F.R. 15878, 1986). • Virgin Islands Coral Reef National Monument protects coral reefs as essential habitat for sustaining the fragile biological communities in this region (Proclamation 7399, 2001). • Red Hind Spawning Aggregation Areas west of Puerto Rico are federally managed. All three areas prohibit fishing during the spawning season by implementing area closures from December to February (50 C.F.R. § 622, 1996). A later amendment to this rule established a marine conservation district east of Puerto Rico, in which fishing activity and anchoring by fishing vessels are banned to protect its coral reef habitat (50 C.F.R. § 622, 1999)

Which groups manage and enforce MPAs?  

Through related domestic legislation and international trade law (Table 1), several U.S. federal agencies play important roles in the protection of coral reef environments, among their other duties. In 1998, Presidential Executive Order 13089 (Coral Reef Protection) established the United States Coral Reef Task Force (U.S.CRTF), which includes representatives from the Department of the Interior, the Department of Commerce, NOAA, the Environmental Protection Agency (EPA), the Department of Defense, the National Science Foundation, the Department of Transportation, the Department of Agriculture, the Department of State, the Agency for International Development, and the National Aeronautics and Space Administration (Executive Order 13089, 1998). The U.S.CRTF is charged with leading U.S. stewardship of coral reef ecosystems by supporting scientific research, mapping, monitoring, restoration, international cooperation, and the reduction of threats to reefs in coordination with other stakeholder groups. 

The groundbreaking Coral Reef Conservation Act of 2000 authorized major contributions to the research, mapping, monitoring, conservation, and management of coral reefs, in large part through the development of a National Action Strategy in consultation with USCRFT and the establishment of NOAA’s Coral Reef Conservation Program (CRCP) (Coral Reef Conservation Act of 2000, 2000). The CRCP is one of few federal programs whose direct mission is to address coral reef conservation efforts and the only one with a legislative mandate. In addition to supporting the USCRTF, the CRCP’s multifaceted work involves funding coral research, delivering sound scientific information and tools for management, establishing core partnerships with various stakeholders, and capacity building to help local staff members implement projects that address threats and restore habitats, among other functions. The monumental work of this program relies on federal funds appropriated by Congress. In addition, the U.S. Fish and Wildlife Service manages 10 coral reef National Wildlife Refuges in the Pacific and enforces international trade laws, which regulate the import and export of corals for jewelry or the aquarium trade. The Environmental Protection Agency protects coral reefs by implementing Clean Water Act programs that maintain water quality in watersheds and coastal zones of coral reef areas. While these functions are important, their pertinence to coral reefs is not congressionally mandated. 

A summary of other key domestic policies and the primary agencies responsible for them is shown in Table 1. There are also several international policies that impact coral reefs, though the U.S. is notably absent from several (see gaps section below). The U.S. is contracting party of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES, 1973), which serves to regulate international trade of animal and plant samples in order to promote conservation and reduce the risk of overexploitation and extinction. All hard coral species (Scleractinia spp.) are listed in the CITES Appendix II, and transport of live specimens or products of these species requires a CITES permit (Resolution Conf. 9.24 Rev. CoP17, 1994).

What’s missing: Management and policy gaps in coral reef conservation

  The U.S. stance on ocean policy has varied across administrations. Mostly recently it has shifted from an emphasis on conservation and climate to a focus on economic and security concerns (Executive Order No. 13840, 2018). While the stringency of coral reef conservation has fluctuated, it remains indisputable, as described above, that coral reefs provide substantial economic benefits to many U.S. sectors, in addition to their contributions to biological diversity and ecosystem health. Executive Order 13840, Regarding the Ocean Policy to Advance the Economic, Security, and Environmental Interests of the United States, calls to “facilitate the economic growth of coastal communities and promote ocean industries”, among other priorities (Executive Order 13840, 2018). It is clear from the lengthy list of ecosystem services that preservation of coral reefs is necessary for economic growth and security of many coastal communities.

While there are legal mechanisms (e.g., MPAs) to protect coral reefs under U.S. jurisdiction, gaps often remain in implementation and enforcement. For instance, many MPAs are in remote places where enforcement is difficult, even for countries with substantial resources [66, 67]. When properly enforced, protection can help alleviate some, though not all, stressors. An evaluation of the ecological performance of MPAs in the U.S. Virgin Islands revealed that coral reefs outside MPAs showed larger declines in ecosystem performance, such as lower density of fish including adult snappers [68]. Notably, the amount of live coral cover decreased both inside and outside MPAs during the study period due to bleaching events and hurricane damage, pointing to the importance of global stressors in driving community structure [68]. Table 2 details additional policy tools to tackle local stressors and provides some examples of gaps in implementation at the municipal, state, and national level. 

Key coral reef legislation also requires immediate attention. The Coral Reef Conservation Act of 2000 expired 15 years ago. Reauthorization attempts thus far have either failed or remained stagnant in Congress. Most recently, the Restoring Resilient Reefs Act of 2019 was introduced in both the House of Representatives (H.R. 4160) and the Senate (S. 2429) is a bipartisan and bicameral bill to reauthorize and modernize the Coral Reef Conservation Act of 2000. This bill, however, has not yet proceed past the introduction stage. This legislation would a provide a strong base for coordinated national efforts as well as provides $\$$160 million of federal funding for the next five years for domestic reef management, conservation, and restoration. Such increases in funding are desperately needed. For instance, the budget for CRCP has held steady around $\$$27 million per year over the past ten years [69]. This stagnant budget supports work that is becoming increasingly demanding and urgent. Given the vast monetary value that coral reefs represent to the U.S., increasing this and other program budgets would expand their capacity and impact. 

On a global geopolitical level, the U.S. has the potential to influence coral reef management in other regions, as well. The USCRTF has active working groups that address specific issues and produce incredibly detailed global, regional, and local recommendations based on science that need to be considered in national policy. For example, 60% of the aquarium fish trade is imported into the U.S., with almost 90% originating from Pacific regions [70, 71]. While the U.S.AID’s program in the Philippines and Indonesia are working to improve problems around both overfishing and destructive fishing (e.g. cyanide or dynamite fishing), the program’s limited geographic scope and jurisdiction makes it difficult to coordinate and enforce the larger-scale regional efforts that are needed. To address this, the USCRTF has recommended leveraging work with the Asian Pacific Economic Cooperation (APEC) forum and building a strategic partnership with the South Pacific Region Environmental Program [72]. 

More broadly, however, the U.S. is not party to some major international conventions that would benefit coral reef ecosystems:

• The United Nations Convention on the Law of the Sea (1982) defines the rights and responsibilities of countries with respect to ocean use in order to maintain peaceful relations between governments (U.N. Convention on the Law of the Sea, 1982). Currently, the U.S. has signed but not ratified the agreement, a move that may jeopardize future claims to ocean resources [73]. Within the agreement, the extent of coral reefs is used to help define the limits of territorial seas, and thus the continued loss of reefs has strong implications for future designations of maritime boundaries.

• The United Nations Convention on Biological Diversity (1992) is a comprehensive agreement between 196 parties dedicated to the conservation and sustainable use of biodiversity. Although President Clinton signed the agreement in 1993 and had support from the Senate Foreign Relations Committee, a Senate vote to ratify it was never held (U.S. Senate Committee on Foreign Relations Activities & Reports). The U.S. is party to smaller scale agreements, like the Inter-American Convention for the Protection and Conservation of Sea Turtles and the Specially Protected Areas and Wildlife Protocol.

Saving corals: Restoration, conservation, and research efforts

Despite legislative protections against local impacts, coral reefs have continued to deteriorate mainly due to increasing global temperatures and disease [6, 74]–[76]. This widespread loss has prompted large-scale restoration efforts, involving government programs (e.g. NOAA Coral Reef Conservation Program), non-governmental organizations (e.g. The Nature Conservancy, SECORE International, etc.), academic institutions, and community groups. The Coral Restoration Consortium, which includes international leaders of multiple coral stakeholder groups, provides a collaborative framework that is crucial for successful coral reef restoration on a global scale (crc.reefresilience.org). 

Coral restoration aims to increase the number of healthy adult corals on reefs. However, as corals may reproduce asexually (usually via fragmentation) or sexually, restoration also involves promoting asexual and sexual reproductive processes on reefs to increase coral abundance (Figure 3C) [77, 78]. In the U.S., the largest restoration efforts are in Florida, for the fast-growing staghorn and elkhorn Acropora coral species (the same ones that nearly died out across the Caribbean in 1970s). The Coral Restoration Foundation has led this effort since 2007. To date, the foundation has transplanted over 100,000 coral fragments onto the Florida Reef Tract (www.coralrestoration.org). Coral nurseries in Puerto Rico and the Virgin Islands have also successfully transplanted tens of thousands of coral fragments [79]. Mote Marine Laboratory and Aquarium (www.mote.org), in addition to managing their own underwater coral nursery, has built upon this effort in recent years by developing a method to micro-fragment and fuse typically slower growing corals, thereby speeding up the cultivation process for other species [80].

While increasing asexual reproduction on reefs can help maintain coral populations, only sexual reproduction can generate new genetic diversity. SECORE International (www.secore.org) is leading global coral restoration efforts by regularly producing millions of coral offspring from naturally released eggs and sperm. Once these newborn corals attach to tiles, they are transplanted onto a natural reef, where in time they can mature and contribute to the next generation [81, 82]. However, restoration success (having transplanted colonies grow and sexually reproduce) is contingent upon the environmental conditions being suitable for corals, since stressors such as poor water quality can significantly reduce fertilization [83, 84] and subsequent bleaching can kill transplanted colonies. Increasing the efficiency of coral restoration, e.g. by transplanting coral colonies that are mostly likely to survive and reproduce, in conjunction with improving local environmental conditions will help managers meet the challenges of continued coral population declines [85].

Despite the benefits restoration can offer at a local scale, the pace of climate change is beyond what most corals can handle. Novel research initiatives exploring the possibilities of assisted evolution in corals and their algal symbionts (Figure 3A), such as selective breeding for heat tolerance, continue to gain traction within science and management communities [2, 95]. Other efforts to save coral diversity include genetic repositories (where live corals are maintained in aquaria or nurseries) and coral sperm banks through cryopreservation [96].

Recent initiatives have shifted focus from individual species to restoring and protecting entire reef ecosystems. NOAA recently launched Mission: Iconic Reefs, which targets seven reefs in the Florida Keys National Marine Sanctuary for multi-phased, active restoration. This will involve removing invasive species and algae, transplanting both fast and slow-growing coral species, and increasing the population of other beneficial species like sea urchins and Caribbean king crabs. Another unprecedented coral conservation project is the 50 Reefs Initiative (led by The Ocean Agency), which identified reefs likely to survive climate change and repopulate nearby reefs once the climate stabilizes [97]. The approach developed by the 50 Reefs Initiative will allow managers to maximize long term conservation benefits while reducing the risks of devoting limited resources to reefs that are unlikely to withstand projected warming and wave damage  from increasingly intense cyclones [97].

Saving corals for the long term: Addressing climate change is our largest policy gap

Even with these monumental restoration and conservation efforts, the predictions for climate change-driven coral reef loss are grim. The 2018 IPCC report warned that 1.5◦C increase in global temperatures would correspond to 70-90% coral reef decline, and a 2◦C rise could result in the loss of greater than 99% of reefs [98]. Aggressive international and domestic commitments to reduce greenhouse gas emissions are necessary if coral reefs are to remain functional ecosystems for the benefit of future generations. We, therefore, find it critical to highlight major policies and agreements surrounding greenhouse gas emissions.

The Clean Air Act (42 U.S.C. § 7401, 1963) and the jurisdiction of the Environmental Protection Agency

• 2007 – Massachusetts vs. EPA, the U.S. Supreme Court ruled that greenhouse gases are pollutants under The Clean Air Act, and should be regulated as such. • 2010 – Tailoring Rule by EPA establishes emission thresholds and a process for permitting carbon dioxide equivalent emissions for large, stationary emitters like power plants (75 F.R. 31513, 2010). • 2014 – Utility Air Regulatory Group v. EPA, the U.S. Supreme Court confirmed the jurisdiction of the EPA to regulate greenhouse gas emissions. • 2015 – Clean Power Plan by EPA established final emission guidelines for states to use in limiting greenhouse gas emissions from power generators (80 F.R. 64661, 2015). • 2017 – Executive Order 13783 by President Trump prompts the EPA to review the Clean Power Plan as a potential burden to the development of domestic energy resources. The formal process to repeal the plan was initiated that year (Executive Order 13783, 2017). • 2019 – Affordable Clean Energy Rule by the EPA replaces the Clean Power Plan, stating that the Clean Power Plan overstepped the authority attributed to the EPA under the Clean Air Act (84 F.R. 32520, 2019). Instead, the Affordable Clean Energy Rule places the responsibility of developing standards for CO2 emissions from existing coal-fired power plants on the states. The rule also points to heat rate improvement measures as the best strategy for reducing emissions, rather than shifting some power generation to renewable energy sources.

The move from the Clean Power Plan (CPP) to the Affordable Clean Energy Rule (ACE) demonstrated a clear shift away from federal regulation of greenhouse gas emissions, and federal promotion of renewable energy use. The CPP was enacted to reduce greenhouse gas emissions from power generation by 32% compared from 2005 levels by 2030 (U.S. Environmental Protection Agency 2015). In contrast, the ACE does not set limits on carbon emissions, and instead relies on individual states to take the initiative to regulate greenhouse gas emissions from power plants. The emission reductions projected under the CPP totaled around 870 million tons, compared to 11 million tons under the ACE (U.S. Environmental Protection Agency 2015, 2019). Given the sensitivity of corals to bleaching under increasing global temperatures caused by elevated greenhouse gas emissions [98] this change in legislation undermines efforts to protect and restore coral reefs.

The lack U.S. leadership in reducing global greenhouse gas emissions is further demonstrated by its absence from several international agreements:

• 2012 – Kyoto Protocol operationalizes the United Nations Framework Convention on Climate Change by holding industrialized countries to their committed target reductions in greenhouse gas emissions. The U.S. signed but never ratified the agreement. The Doha Amendment to the Kyoto Protocol includes assigned percentage reductions of greenhouse gas emissions by 2020 for individual countries (not including the U.S.), but has not yet entered into force due to the lack of ratification (United Nations, 2012).

• 2015 – The United Nations Framework Convention on Climate Change Paris Agreement strives to limit average global warming to well below 2◦C relative to preindustrial measurements, with an overall goal to keep the temperature increase to a maximum of 1.5◦C (United Nations, 2015). The U.S. president announced the U.S. withdrawal from this agreement in 2017, due to the negative impact it would have on the U.S. economy (Trump, 2017). However, withdrawing from the Paris Agreement takes four years given the start date of November 4, 2016 (United Nations, 2015), so the earliest possible official withdrawal date is not until November 4, 2020.

Progress towards the global reduction of greenhouse gas emissions continues with the carbon market systems established by other parties to the Paris Agreement. The European Union (EU) Emissions Trading System was the first, and continues to be the largest. The EU system functions by setting a cap on the total amount of specific greenhouse gases emitted, which is lowered over time. Individual companies are then assigned emission allowances for free or purchase allowances via auctions, which they can trade amongst each other [99]. The EU is actively supporting China – the country with the highest annual emissions [100] – in the development of a nationwide carbon emissions trading system [101]. Similar carbon markets already exist in the U.S., but only a small minority of states participate [102, 103], limiting realized emission reductions due to the transfer of electricity generation to unregulated sectors [104].

Despite these federal decisions to abstain from strong action against the root cause of climate change, many states have made their own commitments to reduce greenhouse gas emissions consistent with the Paris Agreement. The United States Climate Alliance was formed in response to the impending U.S. withdrawal from the agreement, and includes 24 states and Puerto Rico. The U.S. governors in the alliance have promised to enact policies that reduce emissions 26-28% below 2005 levels by 2025, track and report progress to the international community, and promote clean energy within their states.

Coral reefs are one of our planet’s most valuable ecosystems [5]. The coastal protection, tourism revenue, biodiversity services, and drug discovery potential of coral reefs are worth trillions of dollars annually [105]. The continued loss of coral reef habitat will represent a significant economic cost to many countries around the world, including the U.S.. The recent actions taken by the U.S. government in national and international policy arenas fall short of an effective strategy to address the greatest global threat to reefs: climate change resulting from increased greenhouse gas emissions. As a country with the second highest annual emissions and the highest cumulative emissions since 1751 [100], the U.S. should take a leading role in the battle against climate change, thereby helping preserve coral reefs for current and future generations. Local management efforts should prioritize the protection of coral reef habitats and strive to mitigate local stressors as much as possible. However, a national and international effort to limit the main source of coral death – increasing global temperatures – is imperative for the future survival of these vibrant marine ecosystems.

Rivera H. E., Chan A. N. & Luu V. Coral reefs are critical for our food supply, tourism, and ocean health. We can protect them from climate change. MIT Science Policy Review 1 , 18-33 (2020).

Open Access

This MIT Science Policy Review article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ic

Legislation Cited (in order of appearance in text, then tables)

• Executive Order 13158, Marine Protected Areas, 65 F.R. 34909 (May 26, 2000). https://www. federalregister.gov/documents/2000/05/ 31/00-13830/marine-protected-areas

• National Marine Sanctuaries Act, 16 U.S.C. §§ 1431 et seq. (1972).

• Antiquities Act, 54 U.S.C. §§ 320301-320303 (1906).

• Proclamation 8031, Establishment of the Northwestern Hawaiian Islands Marine National Monument, 71 F.R. 36441 (June 15, 2006). https://www. federalregister.gov/documents/2006/ 06/26/06-5725/establishment-of-thenorthwestern-hawaiian-islands-marinenational-monument

• Proclamation 9478, Papahanaumoku ¯ akea Marine ¯ National Monument Expansion 81 FR 60225 (August 31, 2016). https://www.federalregister. gov/documents/2016/08/31/2016-21138/ papahamacrnaumokuamacrkea-marinenational-monument-expansion

• Proclamation 8336, Establishment of the Pacific Remote Islands Marine National Monument, 74 F.R. 1565 (January 6, 2009). https://www. federalregister.gov/documents/2009/01/ 12/E9-500/establishment-of-the-pacificremote-islands-marine-national-monument

• Florida Keys National Marine Sanctuary, 15 C.F.R. part 922, subpart P; Pub. L. 101–605, Nov. 16, 1990, 104 Stat. 3089, as amended by Pub. L. 102–587, title II, §§2206, 2209, Nov. 4, 1992, 106 Stat. 5053 , 5054.

• Flower Garden Banks National Marine Sanctuary, 56 F.R. 63634, Dec. 5, 1991; 60 F.R. 10312, Feb. 24, 1995; 15 C.F.R. part 922, subpart L; Pub. L. 100–627, title II, §205(a)(2), Nov. 7, 1988, 102 Stat. 3217 ; Pub. L. 102–251, title I, §101, Mar. 9, 1992, 106 Stat. 60 ; Pub. L. 104–283, §8, Oct. 11, 1996, 110 Stat. 3366 .

• Proclamation 8335, Establishment of the Marianas Trench Marine National Monument, 74 F.R. 1555 (January 6, 2009). https://www. federalregister.gov/documents/2009/01/ 12/E9-496/establishment-of-the-marianastrench-marine-national-monument

• National Marine Sanctuary of American Samoa (former Fagatele Bay National Marine Sanctuary), 51 F.R. 15878, Apr. 29, 1986; 15 C.F.R. part 922, subpart J; 77 F.R. 43942, July 26, 2012, effective Oct. 15, 2012 (see 77 F.R. 65815).

• Proclamation 7399, Establishment of the Virgin Islands Coral Reef National Monument, 3 C.F.R. 7399 (January 17, 2001). https://www.govinfo.gov/content/ pkg/WCPD-2001-01-22/pdf/WCPD-2001-01-22- Pg156.pdf

• Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of Puerto Rico and the U.S. Virgin Islands; Red Hind Spawning Aggregations, 50 C.F.R. § 622 (1996).

• Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Coral Reef Resources of Puerto Rico and the U.S. Virgin Islands; Amendment 1, 50 C.F.R. § 622 (1999).

• Executive Order 13089, Coral Reef Protection, 63 F.R. 32701 (June 11, 1998). https://www.govinfo. gov/content/pkg/FR-1998-06-16/pdf/98- 16161.pdf

• Coral Reef Conservation Act, 16 U.S.C. §§ 6401 et seq. (2000).

• Convention on International Trade in Endangered Species of Wild Fauna and Flora, March 3rd, 1973, 993 U.N.T.S. 243 [hereinafter CITES].

• Criteria for Amendment of Appendices I and II, Resolution Conf. 9.24 (Rev. CoP17), Fort Lauderdale (1994). https://cites.org/sites/default/files/ document/E-Res-09-24-R17.pdf

• Executive Order 13840, Ocean Policy To Advance the Economic, Security, and Environmental Interests of the United States, 83 FR 29431 (June 22, 2018). https: //www.federalregister.gov/documents/2018/ 06/22/2018-13640/ocean-policy-to-advancethe-economic-security-and-environmentalinterests-of-the-united-states

• Restoring Resilient Reefs Act of 2019. 116 U.S.C. §§ H.R. 4160 et seq. (2019).

• Restoring Resilient Reefs Act of 2019. 116 U.S.C. §§ S.2429 et seq. (2019).

• United Nations Convention on the Law of the Sea, December 10, 1982, 1833 U.N.T.S. 397.

• United Nations Convention on on Biological Diversity, June 5, 1992, 1760 U.N.T.S. 69.

• The Clean Air Act of 1963, 42 U.S.C. § 7401 (1963).

• Massachusetts et al. v. Environmental Protection Agency et al., 549 U.S. 497 (2007).

• Prevention of Significant Deterioration and Title V Greenhouse Gas Tailoring Rule, 40 C.F.R. §§ 51-52 and 40 C.F.R. §§ 70-71, 75 F.R. 31513 (August 2, 2010). https://www.federalregister.gov/documents/ 2010/06/03/2010-11974/prevention-ofsignificant-deterioration-and-title-vgreenhouse-gas-tailoring-rule

• Utility Air Regulatory Group v. Environmental Protection Agency et al., 573 U.S. 302 (2014).

• Carbon Pollution Emission Guidelines for Existing Stationary Sources: Electric Utility Generating Units (Clean Power Plan), 40 C.F.R. § 60, 80 F.R. 64661 (December 22, 2015). https://www. federalregister.gov/documents/2015/10/23/ 2015-22842/carbon-pollution-emissionguidelines-for-existing-stationarysources-electric-utility-generating

• Executive Order 13783, Promoting Energy Independence and Economic Growth, 82 F.R. 16093 (March 28, 2017). https://www.federalregister.gov/documents/ 2017/03/31/2017-06576/promoting-energyindependence-and-economic-growth

• Repeal of the Clean Power Plan; Emission Guidelines for Greenhouse Gas Emissions From Existing Electric Utility Generating Units; Revisions to Emission Guidelines Implementing Regulations (Affordable Clean Energy Rule), 40 C.F.R. § 60, 84 F.R. 32520 (September 6, 2019). https://www.federalregister.gov/ documents/2019/07/08/2019-13507/repealof-the-clean-power-plan-emissionguidelines-for-greenhouse-gas-emissionsfrom-existing

• US Environmental Protection Agency (EPA) 2015, Regulatory Impact Analysis for the Clean Power Plan Final Rule https://epa.gov/ttnecas1/docs/ ria/utilities_ria_final-clean-power-planexisting-units_2015-08.pdf

• US Environmental Protection Agency (EPA) 2019, Regulatory Impact Analysis for the Repeal of the Clean Power Plan, and the Emission Guidelines for Greenhouse Gas Emissions from Existing Electric Utility Generating Units https://www.epa.gov/sites/production/files/2019-06/documents/utilities_ria_ final_cpp_repeal_and_ace_2019-06.pdf

• United Nations, Kyoto Protocol to the United Nations Framework Convention on Climate Change, Doha Amendment to the Kyoto Protocol, C.N.718.2012.TREATIES-XXVII.7.c (December 8, 2012).

• United Nations, Paris Agreement, December 12th, 2015, T.I.A.S. No. 16-1104.

• Trump, D.J. (2017). Statement by President Trump on the Paris Climate Accord. https://www.whitehouse. gov/briefings-statements/statementpresident-trump-paris-climate-accord/

• Beaches Environmental Assessment and Coastal Health Act of 2000, 33 U.S.C. §§ 1313 et seq. (2000).

• Federal Water Pollution Control Act (Clean Water Act), 33 U.S.C. §§ 1251 et seq. (1972).

• Coastal Zone Management Act of 1972, 16 U.S.C. §§ 1451 et seq. (1972).

• The Endangered Species Act of 1973, 16 U.S.C. §§ 1531 et seq. (1973).

• Endangered and Threatened Wildlife and Plants; Final Rule to List the Dusky Sea Snake and Three Foreign Corals Under the Endangered Species Act, 50 C.F.R. §§ 223-224, 80 F.R. 60560 (November 6, 2015). https://www.federalregister.gov/documents/ 2015/10/07/2015-25484/endangered-andthreatened-wildlife-and-plants-finalrule-to-list-the-dusky-sea-snake-andthree

• Endangered and Threatened Wildlife and Plants: Final Listing Determinations on Proposal to List 66 Reef-Building Coral Species and to Reclassify Elkhorn and Staghorn Corals, 50 C.F.R. § 223, 79 F.R. 53851 (October 10, 2014). https://www. federalregister.gov/documents/2014/09/10/ 2014-20814/endangered-and-threatenedwildlife-and-plants-final-listingdeterminations-on-proposal-to-list-66

• Endangered and Threatened Species: Final Listing Determinations for Elkhorn Coral and Staghorn Coral, 50 C.F.R. § 223, 71 F.R. 26852 (June 8, 2006). https: //www.federalregister.gov/documents/2006/ 05/09/06-4321/endangered-and-threatenedspecies-final-listing-determinations-forelkhorn-coral-and-staghorn-coral

• Magnuson-Stevens Fishery Conservation and Management Act (Fishery Conservation and Management Act of 1976), 16 U.S.C. §§ 1801 et seq. (1976).

• Marine Debris Research, Prevention, and Reduction Act (Marine Debris Act), 33 U.S.C. §§ 1951-1958 (2006).

• The Marine Protection, Research, and Sanctuaries Act, 16 U.S.C. §§ 1431 et seq. and 33 U.S.C. §§ 1401 et seq. (1988).

• The National Environmental Policy Act, 42 U.S.C. §§ 4321 et seq. (1969).

• Notice of Availability of a Draft Environmental Impact Statement for the Florida Keys National Marine Sanctuary Restoration Blueprint; Announcement of Public Meetings, 84 F.R. 45728 (August 30, 2019). https://www.federalregister.gov/ documents/2019/08/30/2019-18783/noticeof-availability-of-a-draft-environmentalimpact-statement-for-the-florida-keysnational

• Rivers and Harbors Appropriation Act of 1899, 33 U.S.C. §§ 401 et seq. (1899).

• The Shore Protection Act, 100 U.S.C. §§ 2601-2609 (1988).

• RPPL No. 10-02. House Bill No. 10-22-1, HD1, SD2, PD1. Tenth Olbill Era Kelulau First Regular Session. §2706 (January 2017).

• The Virgin Islands Revenue Enhancement and Economic Recovery Act of 2017. 2 Bill No. 32-0005. §1. (2017).

• U.S. Environmental Protection Agency. (2002). Asset Management for Sewer Collection Systems Fact Sheet. https://www3.epa.gov/npdes/pubs/ assetmanagement.pdf

• White House (2018). Legislative Outline for Rebuilding Infrastructure in America. https: //www.whitehouse.gov/wp-content/uploads/ 2018/02/INFRASTRUCTURE-211.pdf

• The White House (2020). Historic Investment in America’s Infrastructure: A Budget for America’s Future. https://www.whitehouse.gov/wpcontent/uploads/2020/02/FY21-Fact-SheetInfrastructure.pdf

• Water Infrastructure and Improvement Act. 115 U.S.C. H.R.7279 (2019)

• Chapter 403.077. (Florida Statutes 2019)

• Florida Department of Environmental Protection Consent Order OGC No. 16-1487 (2017).http: //www.trbas.com/media/media/acrobat/2017- 09/69895557084220-05111531.pdf

• Florida Administrative Code Rule 62-302.530 et seq.

[1] Cinner, J. Coral reef livelihoods. Current Opinion in Environmental Sustainability 7, 65–71 (2014). https://doi. org/10.1016/j.cosust.2013.11.025.

[2] Anthony, K. et al. New interventions are needed to save coral reefs. Nature Ecology and Evolution 1, 1420–1422 (2017). https://doi.org/10.1038/s41559-017-0313-5.

[3] Normille, D. El Niño’s warmth devastating reefs worldwide. Science 352, 15–16 (2016). https://doi.org/10.1126/ science.352.6281.15.

[4] Hughes, T. P. et al. Global warming transforms coral reef assemblages. Nature 556, 492–496 (2018). https://doi. org/10.1038/s41586-018-0041-2.

[5] de Groot, R. et al. Global estimates of the value of ecosystems and their services in monetary units. Ecosystem Services 1, 50–61 (2012). https://doi.org/10.1016/j.ecoser. 2012.07.005.

[6] Hughes, T. P. et al. Global warming and recurrent mass bleaching of corals. Nature 543, 373–377 (2017). https: //doi.org/10.1038/nature21707.

[7] Thompson, J. R., Rivera, H. E., Closek, C. J. & Medina, M. Microbes in the coral holobiont: Partners through evolution, development , and ecological interactions. Frontiers in Cellular and Infection Microbiology 4, 1–20 (2014). https://doi. org/10.3389/fcimb.2014.00176.

[8] Schmidt, T. S., Raes, J. & Bork, P. The Human Gut Microbiome: From Association to Modulation. Cell 172, 1198–1215 (2018). https://doi.org/10.1016/j.cell.2018.02.044.

[9] Woodhead, A. J., Hicks, C. C., Norström, A. V., Williams, G. J. & Graham, N. A. Coral reef ecosystem services in the Anthropocene. Functional Ecology 33, 1023–1034 (2019). https://doi.org/10.1111/1365-2435.13331.

[10] Beck, M. W. et al. The global flood protection savings provided by coral reefs. Nature Communications 9 (2018). https:// doi.org/10.1038/s41467-018-04568-z.

[11] Inc., W. C. U.S. airports, seaports, & border crossings (2020).

[12] Smith, S. V. Coral-reef area and the contributions of reefs to processes and resources of the world’s oceans. Nature 273, 225–226 (1978).

[13] Fisher, R. et al. Species richness on coral reefs and the pursuit of convergent global estimates. Current Biology 25, 500–505 (2015). https://doi.org/10.1016/j.cub. 2014.12.022.

[14] Bruckner, A. Life-saving products from coral reefs. Issues in Science and Technology 18 (Spring 2002).

[15] Schmidtko, A., Lötsch, J., Freynhagen, R. & Geisslinger, G. Ziconotide for treatment of severe chronic pain. New Drug Class 375, 1569–1577 (2010). https://doi.org/10. 1016/S0140-6736(10)60354-6.

[16] Lopez, Y., Cepas, V. & Soto, S. M. The marine ecosystem as a source of antibiotics. In Rampelotto, P. H. & Trincone, A. (eds.) Grand Challenges in Marine Biotechnology, chap. 1, 3–48 (Springer International Publishing, 2018). https:// doi.org/10.1007/978-3-319-69075-9_9.

[17] Green, D. W., Ben-Nissan, B., Yoon, K. S., Milthorpe, B. & Jung, H. S. Natural and Synthetic Coral Biomineralization for Human Bone Revitalization. Trends in Biotechnology 35, 43–54 (2017). https://doi.org/10.1016/j.tibtech.2016.10.003.

[18] Altmann, K. H. Drugs from the oceans: Marine natural products as leads for drug discovery. Chimia 71, 646–651 (2017). https://doi.org/10.2533/chimia.2017.646.

[19] Jiménez, C. Marine Natural Products in Medicinal Chemistry. ACS Medicinal Chemistry Letters 9, 959–961 (2018). https: //doi.org/10.1021/acsmedchemlett.8b00368.

[20] FAO. The state of the world fisheries and aquaculture 2018 – Meeting the sustainable development goals. Tech. Rep., United Nations, Rome, Italy (2018).

[21] Brander, L. & Van Beukering, P. The Total Economic Value of U.S. Coral Reefs: A Review of the Literature. Tech. Rep., NOAA Coral Reef Conservation Program, Silver Spring, MD (2013). URL https://www.ncei.noaa. gov/data/oceans/coris/library/NOAA/CRCP/other/ other_crcp_publications/TEV_US_Coral_Reefs_ Literature_Review_2013.pdf.

[22] Authority, G. B. R. M. P. Great Barrier Reef Outlook Report 2019. Tech. Rep., Great Barrier Reef Marine Park Authority, Townsville, Australia (2019). URL http://elibrary.gbrmpa.gov.au/jspui/bitstream/ 11017/3474/10/Outlook-Report-2019-FINAL.pdf.

[23] Spalding, M. et al. Mapping the global value and distribution of coral reef tourism. Marine Policy 82, 104–113 (2017). https: //doi.org/10.1016/j.marpol.2017.05.014.

[24] Hoegh-Guldberg, O., Pendleton, L. & Kaup, A. People and the changing nature of coral reefs. Regional Studies in Marine Science 30, 100699 (2019). https://doi.org/10.1016/ j.rsma.2019.100699.

[25] Glynn, P. W. Coral reef bleaching: Ecological perspectives. Coral Reefs 12, 1–17 (1993). https://doi.org/10.1007/ BF00303779.

[26] Davy, S. K., Allemand, D. & Weis, V. M. Cell Biology of Cnidarian-Dinoflagellate Symbiosis. Microbiology and Molecular Biology Reviews 76, 229–261 (2012). https:// doi.org/10.1128/MMBR.05014-11.

[27] Heron, S. F., Maynard, J. A., van Hooidonk, R. & Eakin, C. M. Warming trends and bleaching stress of the world’s coral reefs 1985–2012. Scientific Reports 6, 38402 (2016). https:// doi.org/10.1038/srep38402.

[28] Sully, S., Burkepile, D. E., Donovan, M. K., Hodgson, G. & van Woesik, R. A global analysis of coral bleaching over the past two decades. Nature Communications 10, 1264 (2019). https://doi.org/10.1038/s41467-019-09238-2.

[29] Barkley, H. C. et al. Repeat bleaching of a central Pacific coral reef over the past six decades (1960-2016). Nature Biology Communications 1, 177 (2018). https://doi.org/ 10.1038/s42003-018-0183-7.

[30] Halpern, B. S. et al. An index to assess the health and benefits of the global ocean. Nature 488, 615–620 (2012). https: //doi.org/10.1038/nature11397.

[31] Bikes, S. N. Australia’s Great Barrier Reef suffers most extensive coral bleaching (2020). URL https://news. trust.org/item/20200604055724-nbjg4/.

[32] Hughes, T. P. et al. Climate change, human impacts, and the resilience of coral reefs. Science 301, 929–33 (2003). URL http://www.ncbi.nlm.nih.gov/pubmed/12920289. https://doi.org/10.1126/science.1085046.

[33] Hughes, T. P. et al. Spatial and temporal patterns of mass bleaching of corals in the Anthropocene. Science 359, 80–83 (2018). URL www.sciencemag.org/content/359/6371/ 80/suppl/DC1. https://doi.org/10.1126/science. aan8048.

[34] Green, E. P. & Bruckner, A. W. The significance of coral disease epizootiology for coral reef conservation. Biological Conservation 96, 347–361. https://dx.doi.org/10. 1016/S0006-3207(00)00073-2.

[35] Gladfelter, W. B. White-band disease in Acropora palmata: Implications for the sturucture and growth of shallow reefs. Bulletin of Marine Science 32, 639–643 (1982).

[36] Walton, C. J., Hayes, N. K. & Gilliam, D. S. Impacts of a regional, multi-year, multi-species coral disease outbreak in Southeast Florida. Frontiers in Marine Science 5, 1–14 (2018). https://doi.org/10.3389/fmars.2018.00323.

[37] Leggat, W. P. et al. Rapid Coral Decay Is Associated with Marine Heatwave Mortality Events on Reefs. Current Biology 29, 2723–2730.e4 (2019). https://doi.org/10.1016/j. cub.2019.06.077.

[38] Redding, J. E. et al. Link between sewage-derived nitrogen pollution and coral disease severity in Guam. Marine Pollution Bulletin 73, 57–63 (2013). https://doi.org/10.1016/j. marpolbul.2013.06.002.

[39] Miller, M. W. et al. Detecting sedimentation impacts to coral reefs resulting from dredging the Port of Miami, Florida USA. PeerJ 2016, 1–19 (2016). https://doi.org/10.7717/ peerj.2711.

[40] Cunning, R., Silverstein, R. N., Barnes, B. B. & Baker, A. C. Extensive coral mortality and critical habitat loss following dredging and their association with remotely-sensed sediment plumes. Marine Pollution Bulletin 145, 185–199 (2019). https: //doi.org/10.1016/j.marpolbul.2019.05.027.

[41] Vega Thurber, R. L. et al. Chronic nutrient enrichment increases prevalence and severity of coral disease and bleaching. Global change biology 20, 544–54 (2014). https://doi.org/10. 1111/gcb.12450.

[42] Maynard, J. et al. Projections of climate conditions that increase coral disease susceptibility and pathogen abundance and virulence. Nature Climate Change 5, 688–694 (2015). https://doi.org/10.1038/nclimate2625.

[43] Doney, S. C., Fabry, V. J., Feely, R. A. & Kleypas, J. A. Ocean acidification: The other CO2 problem. Annual Review of Marine Science 1, 169–192 (2009). https://doi.org/10.1146/ annurev.marine.010908.163834.

[44] Cyronak, T., Schulz, K. G., Santos, I. R. & Eyre, B. D. Enhanced acidification of global coral reefs driven by regional biogeochemical feedbacks. Geophysical Prospecting 41, 6413–6419 (2014). https://doi.org/10.1002/ 2014GL061184.Received.

[45] Pandolfi, J. M., Connolly, S. R., Marshall, D. J. & Cohen, A. L. Projecting coral reef futures under global warming and ocean acidification. Science 333, 418–22 (2011). https://doi. org/10.1126/science.1204794.

[46] Feely, R. A. et al. Impact of anthropogenic CO2 on the CaCO3 system in the oceans. Science 305, 362–366 (2004). https: //doi.org/10.1126/science.1097329.

[47] DeCarlo, T. M. et al. Coral macrobioerosion is accelerated by ocean acidification and nutrients. Geology 43, 7–10 (2014). https://doi.org/10.1130/G36147.1.

[48] Kurihara, H. Effects of CO2-driven ocean acidification on the early developmental stages of invertebrates. Marine Ecology Progress Series 373, 275–284 (2008). https://doi.org/ 10.3354/meps07802.

[49] Schunter, C. et al. An interplay between plasticity and parental phenotype determines impacts of ocean acidification on a reef fish. Nature Ecology and Evolution 2, 334–342 (2018). https: //doi.org/10.1038/s41559-017-0428-8.

[50] Davies, S. W., Marchetti, A., Ries, J. B. & Castillo, K. D. Thermal and pCO2 stress elicit divergent transcriptomic responses in a resilient coral. Frontiers in Marine Science 3, 112 (2016). https://doi.org/10.3389/fmars.2016.00112.

[51] Foster, T. et al. Dredging and port construction around coral reefs. Tech. Rep., United Nations Environmental Program – PIANC (2010). URL https://www.unepwcmc.org/system/dataset_file_fields/files/000/ 000/099/original/2010_PIANC_Dredging_and_port_ construction_around_coral_reefs_Report_108- 2010_FINAL_VERSION_LowRes.pdf?1398441422.

[52] Valadez-Rocha, V. & Ortiz-Lozano, L. Spatial and temporal effects of port facilities expansion on the surface area of shallow coral reefs. Environmental Management 52, 250–260 (2013). https://doi.org/10.1007/s00267-013-0098-5.

[53] Mora, C., Graham, N. A. & Nyström, M. Ecological limitations to the resilience of coral reefs. Coral Reefs 35, 1271–1280 (2016). https://doi.org/10.1007/s00338-016-1479-z.

[54] Madin, E. M. P. Land reclamation: Halt reef destruction in South China Sea. Nature 524, 291 (2015). https://doi.org/10. 1038/524291a.

[55] McCook, L. J. Macroalgae, nutrients and phase shifts on coral reefs: scientific issues and management consequences for the Great Barrier Reef. Coral Reefs 18, 357–367 (1999). https: //doi.org/10.1007/s003380050213.

[56] Hughes, T. P. et al. Phase shifts, herbivory, and the resilience of coral reefs to climate change. Current Biology 17, 360–365 (2007). https://doi.org/10.1016/j.cub. 2006.12.049.

[57] Stamski, R. E. & Field, M. E. Characterization of sediment trapped by macroalgae on a Hawaiian reef flat. Estuarine, Coastal and Shelf Science 66, 211–216 (2006). https:// doi.org/10.1016/j.ecss.2005.08.010.

[58] Yang, X. et al. Treated Wastewater Changes the Export of Dissolved Inorganic Carbon and Its Isotopic Composition and Leads to Acidification in Coastal Oceans. Environmental Science and Technology 52, 5590–5599 (2018). https:// doi.org/10.1021/acs.est.8b00273.

[59] Burkepile, D. E. & Hay, M. E. Impact of Herbivore Identity on Algal Succession and Coral Growth on a Caribbean Reef. Plos One 5, e8963 (2010). https://doi.org/10.1371/ journal.pone.0008963.

[60] Burkepile, D. E. & Hay, M. E. Nutrient versus herbivore control of macroalgal community development and coral growth on a Caribbean reef. Marine Ecology Progress Series 389, 71–84 (2009). https://doi.org/10.3354/meps08142.

[61] Mumby, P. J. Stratifying herbivore fisheries by habitat to avoid ecosystem overfishing of coral reefs. Journal of Time Series Analysis 35, 266–278 (2014). https://doi.org/10.1111/ faf.12078.

[62] Luckhurst, B. E. & Farrell, S. O. Rapid Recovery of Parrotfish (Scaridae) and Surgeonfish (Acanthuridae) Populations Following the Fish Pot Ban in Bermuda. Proceedings of 66th Gulf and Caribbean Fisheries Institute 301–306 (2013).

[63] Katikiro, R. E. & Mahenge, J. J. Fishers’ Perceptions of the Recurrence of Dynamite-Fishing Practices on the Coast of Tanzania. Frontiers in Marine Science 3, 233 (2016). https: //doi.org/10.3389/fmars.2016.00233.

[64] Pet-Soede, L. & Erdmann, M. An overview and comparison of destructive fishing practices in Indonesia. SPC Live Reef Fish Information Bulletin 28–36 (1998). URL http://www.spc.int/DigitalLibrary/Doc/FAME/ InfoBull/LRF/4/LRF4{_}28{_}Pet-Soede.pdf.

[65] Selig, E. R. & Bruno, J. F. A global analysis of the effectiveness of marine protected areas in preventing coral loss. PLoS ONE 5, e9278 (2010). https://doi.org/10.1371/journal. pone.0009278.

[66] Richardson, M. Protecting America’s Pacific Marine Monuments: A Review of Threats and Law Enforcement Issues. Tech. Rep., Marine Conservation Institute (2012).

[67] Edgar, G. J. et al. Global conservation outcomes depend on marine protected areas with five key features. Nature 506, 216–220 (2014). https://doi.org/10.1038/ nature13022.

[68] Pittman, S. J. et al. Marine Protected Areas of the US Virgin Islands: Ecological Performance Report. NOAA Technical Memorandum NOS NCCOS 187 (2014). URL https://www.ncei.noaa.gov/data/oceans/coris/ library/NOAA/CRCP/project/538/MPAs_Working_ Final_tagged_LQ.pdf.

[69] NOAA. FY10-FY20 Budget Blue Book Summary – NOAA. Tech. Rep., NOAA, Washinton DC, USA.

[70] Rhyne, A. L. et al. Revealing the Appetite of the Marine Aquarium Fish Trade: The Volume and Biodiversity of Fish Imported into the United States. PLoS ONE 7, e35808 (2012). https://doi.org/10.1371/journal.pone.0035808.

[71] Rhyne, A. L., Tlusty, M. F., Szczebak, J. T. & Holmberg, R. J. Expanding our understanding of the trade in marine aquarium animals. PeerJ 2017, e2949 (2017). https://doi.org/10. 7717/peerj.2949.

[72] NOAA. South East Asia Subgroup Report to the U.S. Coral Reef Task Force. Tech. Rep. URL https://www. coralreef.gov/international/mainb.html.

[73] Gavrilov, V., Dremliuga, R. & Nurimbetov, R. Article 234 of the 1982 United Nations Convention on the law of the sea and reduction of ice cover in the Arctic Ocean. Marine Policy 106, 103518 (2019). https://doi.org/10.1016/j.marpol. 2019.103518.

[74] Precht, W. F., Gintert, B. E., Robbart, M. L., Fura, R. & Van Woesik, R. Unprecedented disease-related coral mortality in southeastern Florida. Scientific Reports 6, 31374 (2016). https://doi.org/10.1038/srep31374.

[75] Van Woesik, R. & Randall, C. J. Coral disease hotspots in the Caribbean. Ecosphere 8, e01814 (2017). https://doi.org/ 10.1002/ecs2.1814.

[76] Muller, E. M., Bartels, E. & Baums, I. B. Bleaching causes loss of disease resistance within the threatened coral species Acropora cervicornis. eLife 7, e35066 (2018). URL https: //doi.org/10.7554/eLife.35066.001. https://doi. org/10.7554/eLife.35066.001.

[77] Highsmith, R. C. Reproduction by fragmentation in corals. Marine Ecology Progress Series 7, 207–226 (1982).

[78] Richmond, R. H. & Hunter, C. L. Reproduction and recruitment of corals: comparisons among the Caribbean, the Tropical Pacific, and the Red Sea. Marine Ecology Progress Series 60, 185–203 (1990).

[79] Moulding, A. L., Griffin, S. P., Nemeth, M. I. & Ray, E. C. Caribbean Acropora Outplanting in U.S. Jurisdiction: 1993-2017. NOAA Technical Memorandum NMFS-SER-10 (2020). https://doi.org/10.25923/n4tx-1a30.

[80] Forsman, Z. H., Page, C. A., Toonen, R. J. & Vaughan, D. Growing coral larger and faster: micro-colony-fusion as a strategy for accelerating coral cover. PeerJ 3, e1313 (2015). https://doi.org/10.7717/peerj.1313.

[81] Chamberland, V. F. et al. Restoration of critically endangered elkhorn coral (Acropora palmata) populations using larvae reared from wild-caught gametes. Global Ecology and Conservation 4, 526–537 (2015). https://doi.org/10. 1016/j.gecco.2015.10.005.

[82] Chamberland, V. F. et al. Four-year-old Caribbean Acropora colonies reared from field-collected gametes are sexually mature. Bulletin of Marine Science 92, 263–264 (2016). https://doi.org/10.5343/bms.2015.1074.

[83] Harrison, P. L. & Ward, S. Elevated levels of nitrogen and phosphorus reduce fertilisation success of gametes from scleractinian reef corals. Marine Biology 139, 1057–1068 (2001). https://doi.org/10.1007/s002270100668.

[84] Hédouin, L. & Gates, R. D. Assessing fertilization success of the coral Montipora capitata under copper exposure: Does the night of spawning matter? Marine Pollution Bulletin 66, 221–224 (2013). https://doi.org/10.1016/ j.marpolbul.2012.11.020.

[85] Baums, I. B. et al. Considerations for maximizing the adaptive potential of restored coral populations in the western Atlantic. Ecological Applications 29, 1–23 (2019). https://doi.org/ 10.1002/eap.1978.

[86] D’Angelo, C. & Wiedenmann, J. Impacts of nutrient enrichment on coral reefs: New perspectives and implications for coastal management and reef survival. Current Opinion in Environmental Sustainability 7, 82–93 (2014). https://doi. org/10.1016/j.cosust.2013.11.029.

[87] Singh, G. G. et al. Scientific shortcomings in environmental impact statements internationally. People and Nature 2, 369–379 (2020). https://doi.org/10.1002/pan3. 10081.

[88] Hollick, M. Environmental Impact Assessment: An International Evaluation. Environmental Management 10, 157–178 (1986). https://doi.org/10.1007/BF01867355.

[89] Edwards, P. E. Sustainable financing for ocean and coastal management in Jamaica: The potential for revenues from tourist user fees. Marine Policy 33, 376–385 (2009). https://doi. org/10.1016/j.marpol.2008.08.005.

[90] Lapointe, B. E. et al. Macroalgal blooms on southeast Florida coral reefs: I. Nutrient stoichiometry of the invasive green alga Codium isthmocladum in the wider Caribbean indicates nutrient enrichment. Harmful Algae 4, 1092–1105 (2005). https:// doi.org/10.1016/j.hal.2005.06.004.

[91] Wear, S. L. & Thurber, R. V. Sewage pollution: Mitigation is key for coral reef stewardship. Annals of the New York Academy of Sciences 1355, 15–30 (2015). https://doi.org/10.1111/ nyas.12785.

[92] Naylor, B. Trump and democrats agree to $2 trillion infrastructure package (2019). https://www.npr.org/ 2019/04/30/718677236/trump-and-democratsagree-on-2-trillion-for-infrastructure-butnot-on-how-to-pay.

[93] Helland, E. The enforcement of pollution control laws: Inspections, violations, and self-reporting. Review of Economics and Statistics 80, 1410153 (1998). https://doi. org/10.1162/003465398557249.

[94] Schwarz, W. Implementing a successful I&I removal program in fort lauderdale, FL. In Pipelines 2009: Infrastructure’s Hidden Assets – Proceedings of the Pipelines 2009 Conference, vol. 360, 731–740 (2009). https://doi.org/10.1061/ 41069(360)68.

[95] van Oppen, M. J. H., Oliver, J. K., Putnam, H. M. & Gates, R. D. Building coral reef resilience through assisted evolution. Proceedings of the National Academy of Sciences 112, 2307–2313 (2015). https://doi.org/10.1073/pnas. 1422301112.

[96] Hagedorn, M. et al. Producing Coral Offspring with Cryopreserved Sperm: A Tool for Coral Reef Restoration. Scientific Reports 7, 1–9 (2017). https://doi.org/10. 1038/s41598-017-14644-x.

[97] Beyer, H. L. et al. Risk-sensitive planning for conserving coral reefs under rapid climate change. Conservation Letters 11, 1–10 (2018). https://doi.org/10.1111/conl.12587.

[98] Hoegh-Guldberg, O. et al. Impacts of 1.5C of Global Warming on Natural and Human Systems (2018).

[99] EU Emissions Trading System (EU ETS) | Climate Action. URL https://ec.europa.eu/clima/policies/ets{_}en.

[100] Ritchie, H. & Roser, M. Co and greenhouse gas emissions. Our World in Data (2017). URL https://ourworldindata. org/co2-and-other-greenhouse-gas-emissions.

[101] EUCHINA-ETS: EU-China Emission Trading System.

[102] The Regional Greenhouse Gas Initiative: an initiative of the New England and Mid-Atlantic States of the U.S. URL https:// www.rggi.org/.

[103] California Air Resources Board: California Cap-and-Trade Program. URL https://ww2.arb.ca.gov/our-work/ programs/cap-and-trade-program.

[104] Fell, H. & Maniloff, P. Leakage in regional environmental policy: The case of the regional greenhouse gas initiative. Journal of Environmental Economics and Management 87, 1–23 (2018). https://doi.org/10.1016/j.jeem.2017.10.007.

[105] Costanza, R. et al. Changes in the global value of ecosystem services. Global Environmental Change 26, 152–158 (2014). https://doi.org/10.1016/j. gloenvcha.2014.04.002.

Hanny E. Rivera

Department of Biology, Boston University, Boston, MA

Andrea N. Chan

Department of Biology, Pennsylvania State University, University Park, PA

Victoria Luu

Department of Geosciences, Princeton University, Princeton, NJ

The Importance of Coral Reefs

Corals tutorial.

Coral reefs are some of the most diverse and valuable ecosystems on Earth. Coral reefs support more species per unit area than any other marine environment, including about 4,000 species of fish, 800 species of hard corals and hundreds of other species. Scientists estimate that there may be millions of undiscovered species of organisms living in and around reefs. This biodiversity is considered key to finding new medicines for the 21st century. Many drugs are now being developed from coral reef animals and plants as possible cures for cancer, arthritis, human bacterial infections, viruses, and other diseases.

Healthy coral reefs support commercial and subsistence fisheries as well as jobs and businesses through tourism and recreation. Approximately half of all federally managed fisheries depend on coral reefs and related habitats for a portion of their life cycles. The National Marine Fisheries Service estimates the commercial value of U.S. fisheries from coral reefs is over $100 million. Local economies receive billions of dollars from visitors to reefs through diving tours, recreational fishing trips, hotels, restaurants, and other businesses based near reef ecosystems.

Coral reef structures also buffer shorelines against 97 percent of the energy from waves, storms, and floods, helping to prevent loss of life, property damage, and erosion. When reefs are damaged or destroyed, the absence of this natural barrier can increase the damage to coastal communities from normal wave action and violent storms. Several million people live in U.S. coastal areas adjacent to or near coral reefs. Some coastal development is required to provide necessary infrastructure for coastal residents and the growing coastal tourism industry.

Despite their great economic and recreational value, coral reefs are severely threatened by pollution, disease, and habitat destruction. Once coral reefs are damaged, they are less able to support the many creatures that inhabit them and the communities near them. When a coral reef supports fewer fish, plants, and animals, it also loses value as a tourist destination.

Healthy coral reefs contain thousands of fish and invertebrate species found nowhere else on Earth. Learn more and view a larger image.

In the 1890s, harvesting sponges was second only to cigar-making in economic importance in the Florida Keys. Nets of recently harvested marine sponges are drying on the top of the boat's wheelhouse. Learn more and view a larger image.

Corals Lessons

• What are Corals?
• Zooxanthellae What's That?
• How Do Stony Corals Grow?
• How Do Coral Reefs Form?
• Where Are Coral Reefs Found?
• How Do Corals Reproduce?
• Importance of Coral Reefs
• Natural Threats to Coral Reefs
• Anthropogenic Threats to Corals
• Coral Diseases
• Protecting Coral Reefs
• Roadmap to Resources
• Subject Review (PDF)

Search Education

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

• View all journals
• Explore content
• About the journal
• Publish with us
• Sign up for alerts
• Brief Communication
• Published: 09 January 2023

Coral reefs and coastal tourism in Hawaii

• Bing Lin   ORCID: orcid.org/0000-0002-5905-9512 1 ,
• Yiwen Zeng 1 ,
• Gregory P. Asner   ORCID: orcid.org/0000-0001-7893-6421 2 &
• David S. Wilcove 1 , 3  

Nature Sustainability volume  6 ,  pages 254–258 ( 2023 ) Cite this article

• Biodiversity
• Conservation biology
• Ecosystem services
• Environmental impact

An Author Correction to this article was published on 14 March 2023

This article has been updated

Coral reefs are popular for their vibrant biodiversity. By combining web-scraped Instagram data from tourists and high-resolution live coral cover maps in Hawaii, we find that, regionally, coral reefs both attract and suffer from coastal tourism. Higher live coral cover attracts reef visitors, but that visitation contributes to subsequent reef degradation. Such feedback loops threaten the highest quality reefs, highlighting both their economic value and the need for effective conservation management.

This is a preview of subscription content, access via your institution

Access options

Access Nature and 54 other Nature Portfolio journals

Get Nature+, our best-value online-access subscription

24,99 € / 30 days

cancel any time

Subscribe to this journal

Receive 12 digital issues and online access to articles

111,21 € per year

only 9,27 € per issue

Buy this article

• Purchase on Springer Link
• Instant access to full article PDF

Prices may be subject to local taxes which are calculated during checkout

Similar content being viewed by others

A trans-oceanic flight of over 4,200 km by painted lady butterflies

Habitat amount modulates biodiversity responses to fragmentation

Proof of concept for a new sensor to monitor marine litter from space

Data availability.

The live coral cover data are available in the Zenodo repository ( https://doi.org/10.5281/zenodo.4292660 ). The human activity, site accessibility and water conditions data are available through the Ocean Tipping Points project ( http://www.pacioos.hawaii.edu/projects/oceantippingpoints ) and the Hawaii Statewide GIS Program ( https://geoportal.hawaii.gov/search?collection=Dataset ). Meta reached out to the authors after publication and asked that the original Instagram dataset uploaded in the accompanying Zenodo repository be removed from public access to limit user data exposure and its risk of misuse.

Code availability

Meta reached out to the authors after publication and asked that the original web-scraping script uploaded in the accompanying Zenodo repository be removed from public access to limit user data exposure and its risk of misuse.

Change history

14 march 2023.

A Correction to this paper has been published: https://doi.org/10.1038/s41893-023-01102-y

Hughes, T. P. et al. Global warming and recurrent mass bleaching of corals. Nature 543 , 373–377 (2017).

Article   CAS   Google Scholar  

Arkema, K. K., Fisher, D. M., Wyatt, K., Wood, S. A. & Payne, H. J. Advancing sustainable development and protected area mManagement with social media-based tourism data. Sustainability 13 , 2427 (2021).

Article   Google Scholar  

Tourism in the 2030 Agenda (UNWTO, 2015); https://www.unwto.org/tourism-in-2030-agenda

Cowburn, B., Moritz, C., Birrell, C., Grimsditch, G. & Abdulla, A. Can luxury and environmental sustainability co-exist? Assessing the environmental impact of resort tourism on coral reefs in the Maldives. Ocean Coast. Manag. 158 , 120–127 (2018).

Lin, B. Close encounters of the worst kind: reforms needed to curb coral reef damage by recreational divers. Coral Reefs 40 , 1429–1435 (2021).

Asner, G. P. et al. Large-scale mapping of live corals to guide reef conservation. Proc. Natl Acad. Sci. USA 117 , 33711–33718 (2020).

Wood, S. A., Guerry, A. D., Silver, J. M. & Lacayo, M. Using social media to quantify nature-based tourism and recreation. Sci. Rep. 3 , 2976 (2013).

Wood, S. A. et al. Next-generation visitation models using social media to estimate recreation on public lands. Sci. Rep. 10 , 15419 (2020).

Hausmann, A. et al. Social media data can be used to understand tourists’ preferences for nature-based experiences in protected areas. Conserv. Lett. 11 , e12343 (2018).

Tenkanen, H. et al. Instagram, Flickr, or Twitter: assessing the usability of social media data for visitor monitoring in protected areas. Sci. Rep. 7 , 17615 (2017).

Sessions, C., Wood, S. A., Rabotyagov, S. & Fisher, D. M. Measuring recreational visitation at U.S. National Parks with crowd-sourced photographs. J. Environ. Manag. 183 , 703–711 (2016).

Mancini, F., Coghill, G. M. & Lusseau, D. Using social media to quantify spatial and temporal dynamics of nature-based recreational activities. PLoS One 13 , e0200565 (2018).

Spalding, M. et al. Mapping the global value and distribution of coral reef tourism. Mar. Policy 82 , 104–113 (2017).

van Zanten, B. T. et al. Continental-scale quantification of landscape values using social media data. Proc. Natl Acad. Sci. USA 113 , 12974–12979 (2016).

Department of Land and Natural Resources. Beach Access (Office of Conservation and Coastal Lands, 2013); https://dlnr.hawaii.gov/occl/beach-access/

Mobile LTE Coverage Map (Federal Communications Commission, 2021).

Arkema, K. K. et al. Embedding ecosystem services in coastal planning leads to better outcomes for people and nature. Proc. Natl Acad. Sci. USA 112 , 7390–7395 (2015).

Neuvonen, M., Pouta, E., Puustinen, J. & Sievänen, T. Visits to national parks: effects of park characteristics and spatial demand. J. Nat. Conserv. 18 , 224–229 (2010).

Rodgers, K., Cox, E. & Newtson, C. Effects of mechanical fracturing and experimental trampling on hawaiian corals. Environ. Manag. 31 , 0377–0384 (2003).

Downs, C. A. et al. Toxicopathological effects of the sunscreen UV filter, oxybenzone (benzophenone-3), on coral planulae and cultured primary cells and its environmental contamination in Hawaii and the U.S. Virgin Islands. Arch. Environ. Contam. Toxicol. 70 , 265–288 (2016).

Côté, I. M., Darling, E. S. & Brown, C. J. Interactions among ecosystem stressors and their importance in conservation. Proc. R. Soc. B. 283 , 20152592 (2016).

Bruno, J. F. & Valdivia, A. Coral reef degradation is not correlated with local human population density. Sci. Rep. 6 , 29778 (2016).

Johnson, J. V., Dick, J. T. A. & Pincheira-Donoso, D. Local anthropogenic stress does not exacerbate coral bleaching under global climate change. Glob. Ecol . Biogeogr. (2022).

Darling, E. S., McClanahan, T. R. & Côté, I. M. Combined effects of two stressors on Kenyan coral reefs are additive or antagonistic, not synergistic. Conserv. Lett. 3 , 122–130 (2010).

Severino, S. J. L., Rodgers, K. S., Stender, Y. & Stefanak, M. Hanauma Bay Biological Carrying Capacity Survey 2019–20 2nd Annual Report https://www.honolulu.gov/rep/site/dpr/hanaumabay_docs/Hanauma_Bay_Carrying_Capacity_Report_August_2020.pdf (City and County of Honolulu Parks and Recreation Department, 2020).

Selenium WebDriver (Software Freedom Conservancy, 2022); https://www.selenium.dev/documentation/en/webdriver/

Geospatial Data Portal. Hawaii Statewide GIS Program (Hawaii State Office of Planning, 2017); https://geoportal.hawaii.gov/

Wedding, L. M. et al. Advancing the integration of spatial data to map human and natural drivers on coral reefs. PLoS One 13 , e0189792 (2018).

Nguyen, T., Liquet, B., Mengersen, K. & Sous, D. Mapping of coral reefs with multispectral satellites: a review of recent papers. Remote Sens. 13 , 4470 (2021).

Wicaksono, P., Aryaguna, P. A. & Lazuardi, W. Benthic habitat mapping model and cross validation using machine-learning classification algorithms. Remote Sens. 11 , 1279 (2019).

Download references

Acknowledgements

We thank T. Bearpark, F. Guo, M. Donovan, A. Friedlander, K. Oleson, J. Lecky and J. Abraham for input that informed the study’s conception, design and analyses; T. W. Shawa for help with geospatial modeling; T. Bearpark, A. M. Zuranski, J. A. G. Torres, B. J. Arnold and N. Ondrikova for input on machine learning models; Z. Volenec for the base Selenium WebDriver Python code; the Ocean Tipping Points project and the Hawaii Statewide GIS Program for all site accessibility, human activity and water condition data; and the High Meadows Foundation and Princeton University for ongoing support of this work. Airborne mapping was funded by the Lenfest Ocean Program of The Pew Charitable Trust.

Author information

Authors and affiliations.

Princeton School of Public and International Affairs, Princeton University, Princeton, NJ, USA

Bing Lin, Yiwen Zeng & David S. Wilcove

Center for Global Discovery and Conservation Science, Arizona State University, Hilo, HI, USA

Gregory P. Asner

Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA

David S. Wilcove

You can also search for this author in PubMed   Google Scholar

Contributions

B.L. conceived this study and wrote the first draft; G.P.A. provided the live coral cover data; B.L. and Y.Z. carried out the analyses with input from G.P.A. and D.S.W.; B.L., Y.Z., D.S.W. and G.P.A. contributed to all subsequent iterations of the manuscript.

Corresponding authors

Correspondence to Bing Lin or David S. Wilcove .

Ethics declarations

Competing interests.

The authors declare no competing interests.

Peer review

Peer review information.

Nature Sustainability thanks Robert Richmond and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended data fig. 1 instagram and hawaii tourism authority visitation validation (2018–2021)..

Aggregated Instagram visitation data plotted against yearly daily censuses at the county level conducted by the Hawaii Tourism Authority from 2018 to 2021. The line shows the regression point estimate between variables and the shaded area depicts 95% confidence intervals.

Extended Data Fig. 2 Live coral cover and overall visitation at the 20 most-visited sites in Hawaii.

Overall visitation at the top 20 most-visited sites in the main Hawaiian islands plotted against absolute median live coral cover at each of these sites. The name, location and visitation rank of the top 10 most-visited sites are labeled.

Extended Data Fig. 3 Relationship between overall and on-reef visitation in Hawaii.

The relationship between on-reef and overall visitation across 333 bays and beaches in the main Hawaiian islands. The line depicts the regression point estimate between variables and the shaded region represents 95% confidence intervals.

Extended Data Fig. 4 Littoral buffer construction schematic.

A schematic of how each littoral buffer was constructed in ArcGIS Pro 3.0 for various calculations of benthic composition, human activity, and water conditions at each coastal site.

Extended Data Fig. 5 Histograms of on-reef and overall visitation across coastal sites in Hawaii.

Histograms depicting the discontinuous distribution between high- and low-visitation sites for both overall visitation (top figures) and on-reef visitation (bottom figures) across both the most-visited sites ( n = 100) and all sites ( n = 333).

Supplementary information

Supplementary information, reporting summary, rights and permissions.

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Cite this article.

Lin, B., Zeng, Y., Asner, G.P. et al. Coral reefs and coastal tourism in Hawaii. Nat Sustain 6 , 254–258 (2023). https://doi.org/10.1038/s41893-022-01021-4

Download citation

Received : 14 June 2022

Accepted : 15 November 2022

Published : 09 January 2023

Issue Date : March 2023

DOI : https://doi.org/10.1038/s41893-022-01021-4

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

Quick links

• Explore articles by subject
• Guide to authors
• Editorial policies

Sign up for the Nature Briefing: Anthropocene newsletter — what matters in anthropocene research, free to your inbox weekly.

PERSPECTIVE article

All-inclusive coral reef restoration: how the tourism sector can boost restoration efforts in the caribbean.

• 1 Wave of Change, Iberostar Hotels and Resorts, Bávaro, Dominican Republic
• 2 Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
• 3 Wave of Change, Iberostar Hotels and Resorts, Quintana Roo, Mexico
• 4 Wave of Change, Iberostar Hotels and Resorts, Miami, FL, United States

Following a strong decline in the health of Caribbean coral reefs in the 1970s, disease outbreaks, overfishing, and warming events have continued to push these reefs towards a point of no return. As such, researchers and stakeholders have turned their attention to restoration practices to overcome coral recovery bottlenecks on Caribbean reefs. However, successful restoration faces many challenges, including economical and logistical feasibility, long-term stability, and biological and ecological factors yet to fully understand. The tourism sector has the potential to enhance and scale restoration efforts in the Caribbean, beyond simple financial contributions. Its strengths include long-term presence in several locations, logistical and human resources, and a business case focused on preserving the ecosystem services on which it depends. Here, we present the restoration program of Iberostar Hotels and Resorts which includes a scientific team that incorporates science-based solutions into resort operations to promote reef resilience in the face of climate change. We exemplify the potential of our program to scale up science-based reef restoration in collaboration with academia, local community, and government by presenting the first utilization of the Coral Bleaching Automated Stress System (CBASS) in Latin America and the Latin American Caribbean, with the aim of applying findings on coral thermotolerance directly to Iberostar’s reef restoration program across the Caribbean. This program presents a new model for tourism involvement in coral restoration and illustrates its capacity to scale up existing restoration practices by utilizing the strengths of the sector while maintaining science-based decision making.

Introduction

Reef degradation at global and regional scales.

Global warming is impacting ecosystems at an increasingly alarming rate, with few ecosystems affected as heavily as coral reefs. Ocean warming and acidification are the primary drivers of reef decline on a global scale ( Albright and Langdon, 2011 ; Arias-González et al., 2016 ; Hughes et al., 2018 ), while overfishing, destructive fishing practices, hurricane damage, nutrient and sediment pollution, and poor management of coastal development, among others, synergistically affect reefs at local scales ( Hughes and Connell 1999 ; Gardner et al., 2005 ; Anthony et al., 2014 ; Hughes et al., 2017 ; Hughes et al., 2018 ). As a result, reefs are facing a rapid global decline with a bleak future that will compromise their services to marine ecosystems and society ( Pratchett et al., 2014 ). Due to differences in local pressures, as well as contrasting evolutionary histories and environmental conditions, there is heterogeneity in the state of the reefs across geographic regions, with Caribbean reefs experiencing arguably the strongest negative shift in ecosystem state in recent decades ( Cinner et al., 2016 ; Beyer et al., 2018 ; Cortés-Useche et al., 2019 ; Roff, 2021 ). The deterioration of Caribbean reefs has been documented since the 1970s, with a 50% decline in reef-building coral cover in recent decades and an increasing dominance by macroalgae, sponges, and the hydrozoan Millepora spp. ( Mumby et al., 2007 ; Maliao et al., 2008 ; Cramer et al., 2021 ). This catastrophic decline in coral cover and diversity has largely been attributed to a loss of key herbivores shifting the competitive balance on the benthos in favor of macroalgae ( Lessios et al., 1984 ; Hughes, 1994 ) and an increasing prevalence of coral diseases ( Gladfelter, 1982 ; Precht et al., 2016 ). While these issues persist, a lower coral diversity and difference in evolutionary histories compared to their Indo-Pacific counterparts compromises sexual recruitment, which limits the recover potential of Caribbean coral communities ( Roff, 2021 ). Furthermore, the frequency and intensity of mass bleaching events has increased in the region, since the first region-wide event in 1987 ( McWilliams et al., 2005 ; Manzello, 2015 ), hampering recovery and resilience further. Coral bleaching is now one of the major threats to the region ( Eakin et al., 2010 ). Yet, bleaching events can affect corals heterogeneously at different scales even at the level of species and colonies, promoting the adaptation to future conditions ( Baker et al., 2008 ; Thomas et al., 2019; McClanahan et al., 2020 ). Nonetheless, since the current rate of environmental change is greater than that required for natural adaptation, active intervention through restoration efforts, in combination with efforts to reduce carbon emissions and localized pollution, are increasingly being developed as necessary approaches to aid the recovery of reef-building corals in this region ( Rinkevich, 2015 ; Cortés-Useche et al., 2021 ; Suggett and van Oppen, 2022 ).

Reef restoration bottlenecks in the Caribbean

Global climate action, the establishment of marine protected areas, sustainable fishing practices, and effective management of water systems all are critical tools for reef recovery. Alongside these efforts, coral restoration has the potential to further help recovery of damaged or depleted reefs ( Wilkinson and Souter, 2008 ; Young et al., 2012 ) and there is increasing recognition that it should play a strategic role in protecting critical ecosystem services ( Abelson, 2006 ; Edwards, 2010 ; Chamberland et al., 2015 ; Schopmeyer et al., 2017 ; Calle-Triviño et al., 2018 ; Calle-Triviño et al., 2021 ). Numerous reef restoration projects have been developed in recent years to alleviate bottlenecks of recovery for Caribbean coral communities ( Bayraktarov et al., 2020 ), leading to numerous advancements in techniques to growing and reproducing corals in aquarium settings. Still, there remain major challenges to successful reef restoration due to the slow growth rates of most foundational coral species, limiting the rate at which coral cover and abundance can be increased through outplanting, as well as the feasibility of restoring corals across large spatial scales. This is further constrained by the logistic (diving operations, permits) and economic (materials, equipment, labor) obstacles of underwater work ( Boström-Einarsson et al., 2020 ), as well as a lack of long-term stakeholder engagement ( Hein et al., 2020 ). Most restoration programs in the Caribbean are limited to the species Acropora cervicornis and A. palmata due to their fast growth rates compared to those of other mounding species, ease of fragmentation, historical and functional importance in the Caribbean, and endangered status ( Aronson et al., 2008 ; Lirman et al., 2014 ; Calle-Triviño et al., 2020 ; Cramer et al., 2020 ). Low species diversity as well as often disregarded genetic diversity in these programs can limit functional diversity, sexual recruitment, and genetic exchange, which compromises the adaptive capacity and resiliency of these ecosystems for the future ( Baums et al., 2019 ).

Scaling up the efforts strategically

In order to boost the efficiency and success of reef restoration, as well as build scalable solutions, major barriers to restoration need to be tackled by utilizing the strengths of the different sectors and stakeholders that benefit from coral reef ecosystem services. The tourism sector, especially in coastal tropical areas such as the Latin American Caribbean, constitutes a great benefactor of coral reefs ( Spalding et al., 2017 ). Its potential role as a major contributor to reef restoration, beyond simple financial contributions, could help address many of the above-mentioned challenges ( Hein et al., 2018 ). Here, we present the example of a private sector driven reef restoration program across the Caribbean as a solution to overcome some of the bottlenecks of scalability, economic feasibility, and long-term stability in coral restoration ( Waltham et al., 2020 ; Cortés-Useche et al., 2021 ; Quigley et al., 2022 ). This program incorporates scientific research aimed at solving biological and ecological knowledge gaps that sets the base for restoration operation decisions. The research program is aligned with the current recommendations of the scientific community for reef restoration, such as the selection of resilient species and individuals to accelerate natural selection in the face of climate change, while maintaining the biodiversity and genetic diversity that will support long-term ecosystem resilience ( Baums et al., 2019 ; Caruso et al., 2021 ; Vardi et al., 2021 ; Cunning et al., 2021 ). Moreover, it includes close collaboration with the local community, government, and academia to streamline legal and operational processes for restoration, as well as aligning with the needs and findings of the scientific community, increasing the scope of restoration benefits. By working together, we can utilize the strengths of each sector towards the common goal of restoring reefs to a healthy and productive state.

Tourism sector in reef restoration

Until recent years, the tourism sector has had a purely financial role in restoration projects, and while this is a major strength since the sector has longer-term economic stability than sectors and projects depending on grant cycles and external funding, its involvement can provide a boost to resolve other constraints. Here, we present a novel involvement of the coastal tourism industry in reef restoration ( Figure 1 ) and exemplify it with the case of Iberostar Hotels and Resorts. Iberostar, as with other large networks of hotels and resorts, has an established foundation and resources in different destinations, as well as a network of existing suppliers and multidisciplinary teams that can help solve logistical and geographical bottlenecks. This is a key advantage in terms of scalability, and not only facilitates operating in different destinations, but also standardized and replicable approaches across locations, which can provide valuable information for restoration science. While research permit acquisition is a constraint for many projects to scale up, the tourism sector can advance it through already existing relations and collaboration with governments at each destination. The tourism sector has the capacity to form multidisciplinary teams that support their own restoration programs, such as scientists, operation coordinators, and restoration technicians. These can be strengthened through alliances with actors within the local community (i.e., NGOs, interns, volunteers, employees) and academia.

Figure 1 Reef restoration approach that utilizes the strengths of the tourism sector to overcome common restoration barriers, brings science into the core of restoration decisions and involves government, local community, and NGOs to ensure the resilience of restored reefs. Dashed lines indicate possible areas of collaboration, whereas thick lines indicate direct involvement of the tourism sector.

Approximately half of Iberostar Hotels and Resorts’ global operations are based on coastlines facing the Caribbean basin, and its presence in the region dates to 1993. As of 2020, Iberostar complexes create a combined total of 10.2 km of beachfront in this region. According to the World Resources Institute 500 m resolution map of tropical coral reefs of the world, 80% of Iberostar’s beachfront in this region has reefs within 5 km of their properties totaling almost 6 km 2 of reefs that provide direct ecosystem services to Iberostar’s hotels, operations, and community. Thus, ensuring coral reef protection, resilience, and restoration are a major part of Iberostar’s strategy to improve ecosystem health and profitable tourism by 2030. This strategy is aligned with the objectives of the United Nations Decade of Ecological Restoration (2021-2030) and Sustainable Development Goals ( Claudet et al., 2019 ; Schmidt-Roach et al., 2020 ), and is implemented globally through the Iberostar’s Wave of Change initiative that emerged in 2018, which intends to use the strengths of the tourism sector to tackle the ocean’s biggest challenges while leading sustainable tourism. The Wave of Change reef restoration strategy aims at restoring reefs that value coastal protection first through coral outplanting and propagation, then focusing on increasing fish biomass (important for local food security), and lastly on restoring biodiversity on reefs adjacent to Iberostar hotels.

In order to maximize the success of the conservation and restoration program, Iberostar’s internal team of scientists and coastal health managers collaborate closely with local NGOs to involve the community in their initiatives and support other marine conservation efforts, as well as with the government through collaboration agreements and the constant communication of results and projects, and its participation in sustainability events and activities. Additionally, success of the program relies on employees who are trained to follow the sustainability practices at the heart of the operations and are motivated to participate in environmental activities. Lastly, the program relies on a strong collaboration with academia to reinforce the legitimacy and scope of the scientific program and provide local students with internship opportunities and scholarships. The scientific program addresses lines of research that can inform and make restoration practices more efficient. These lines include asexual reproduction techniques such as reskinning and microfragmentation to address the limitation of slow coral growth rates ( Page, 2013 ; Page and Vaughan, 2014 ); the creation of baselines through photomosaics ( Lirman et al., 2007 ) and reef health assessments ( Lang et al., 2011 ) to enable measuring the impact of the efforts, growing multiple species and genotyping coral individuals in nurseries to ensure species and genetic diversity ( Baums et al., 2019 ), and the selection of thermotolerant coral species and colonies to accelerate natural selection ( Morikawa and Palumbi, 2019 ; Caruso et al., 2021 ; Cunning et al., 2021 ), among other projects. Over four years, Iberostar’s restoration program has already been established in three countries (Dominican Republic, Mexico, and Jamaica), demonstrating the capacity for scalability ( Figure 2 ), with concurrent scientific research also being conducted at these locations. As a demonstration of scalable and applicable reef restoration research with the involvement of the tourism sector, and its alignment with the current need of experimental standardization ( Grottoli et al., 2021 ), we present a collaboration between the science team of Iberostar and academia. The collaboration focuses on identifying heat tolerant corals across Iberostar’s nurseries for inclusion in reef restoration efforts using standardized thermotolerance experiments across Iberostar’s restoration sites. Iberostar established an agreement with Old Dominion University (Virginia, USA) to acquire a portable lab system developed by Dr. Daniel Barshis and colleagues to conduct short-term heat stress experiments ( Voolstra et al., 2020 ; Evensen et al., 2021 ). As part of the collaboration, Iberostar researchers were trained by Dr. Barshis and his team during an experiment conducted together at an Iberostar location. The collaboration also included participation by local partners, employees, internship students, and international clients, promoting knowledge exchange and education between multiple actors ( Schmidt-Roach et al., 2020 ).

Figure 2 Iberostar coral nurseries’ locations across the Caribbean: Mexico (Paraiso Beach in yellow and Cozumel in black), Jamaica (Montego Bay in green) and Dominican Republic (Bavaro Coral Lab in red and Bayahibe in blue).

The use of a portable lab system and acute heat stress experiments for coral restoration

Background and experimental objectives.

Experiments were conducted using the recently developed Coral Bleaching Automated Stress System (CBASS; Voolstra et al., 2020 ; Evensen et al., 2021 ). This highly portable experimental system is designed to conduct standardized thermal stress experiments in a variety of field settings, allowing for the direct comparison of thermal tolerance across coral species and populations. The comparability of heat stress assays is a priority that has recently been highlighted by the scientific community as a need for informing and facilitating reef conservation strategies ( Grottoli et al., 2021 ). While Iberostar already has a coral laboratory in the Dominican Republic where similar thermal stress experiments are being conducted ( Bayraktarov et al., 2020 ), this portable experimental system allows for highly reproducible and standardized experiments to be conducted across the Caribbean, at Iberostar locations where coral restoration programs are being implemented, with the aim of identifying heat tolerant coral individuals for their inclusion in restoration efforts at each location ( Figure 1 ). To date, the CBASS has successfully been used to assay corals across a number of reefs, including American Samoa ( Klepac and Barshis, 2020 ), numerous locations across the Red Sea and Gulf of Aden ( Voolstra et al., 2020 ; Evensen et al., 2021 ; Voolstra et al., 2021 ; Evensen et al., 2022 ), the Great Barrier Reef, and the Galapagos (unpublished data). Notably, the CBASS has recently been used to compare heat tolerances of Acropora cervicornis colonies from six coral nurseries spanning the Florida Reef Tract ( Cunning et al., 2021 ). The experiments presented herein, carried out in Playa Paraíso, Mexico, represent the first utilization of the CBASS in the Latin American Caribbean: a breakthrough for coral science and coral restoration in this region, which is often underrepresented in both fields globally due to language and resource barriers ( Bayraktarov et al., 2020 ). The aim of the experiments was to evaluate the thermal tolerances of four common (yet underrepresented in restoration programs) species on Caribbean reefs: Montastraea cavernosa, Orbicella annularis, O. faveolata and Porites astreoides . For each species, 10 colonies were randomly sampled from Manchoncitos reef (20.759444°N, 86.95°W), located directly offshore from Iberostar’s Playa Paraíso resort, where one of the Iberostar coral nurseries is located. Acute heat stress assays, each lasting 18 h (detailed in Evensen et al., 2021 ), took place over 4 days, assaying one species per day. Response of the corals to thermal stress was assessed through pulse-amplitude modulated (PAM) fluorescence. Thermal thresholds of each species were calculated from PAM measurements (calculating the Fv/Fm ED50, sensu Evensen et al., 2021 ) and thresholds were compared to those from the Dominican Republic, previously obtained in the coral laboratory of Iberostar. Moving forward, we intend to continue assaying common coral species across Iberostar’s locations in the Caribbean to provide a region-wide sensus of coral thermotolerance, as well as conducting longer-term heat stress experiments at Iberostar’s nurseries to compare short- and long-term responses of corals to heat stress ( Figure 2 ).

Field application

Despite consistency in heat stress susceptibility across coral taxa ( Marshall and Baird, 2000 ; Loya et al., 2001 ; Grottoli et al., 2006 ; Guest et al., 2016 ; Singh et al., 2019 ), thermotolerance traits can also be influenced by the environment. Phenotypic plasticity itself can vary depending on the genotype, so the top performing genotype can change depending on the environment, which challenges the selection of heat tolerant individuals for reef restoration. As such, selecting individuals for reef restoration requires testing of locally adapted corals for thermotolerance. Additionally, re-evaluating thermal performance at regular intervals following outplanting could considerably improve our understanding of the mechanisms underpinning thermotolerance and how these are influenced by environmental changes ( Kenkel et al., 2013 ; Palumbi et al., 2014 ; Kenkel et al., 2015 ; Drury et al., 2017 ; Kenkel and Matz, 2017 ; Morikawa and Palumbi, 2019 ; Caruso et al., 2021 ; Cunning et al., 2021 ; Drury and Lirman, 2021 ). The long-term presence of Iberostar at these sites will allow for an unrivaled opportunity to continually assess thermotolerance and bleaching recovery rates for previously assayed and outplanted individuals in the field, as well as their response to natural heat stress events. Bearing in mind the urgency of action to help reefs recover, and the time and resource constraints of conducting multiple experiments, short-term heat stress assays are an advantage for rapid thermotolerance tests with direct application to reef restoration ( Ferse et al., 2021 ). With restoration efforts in the Caribbean to date focusing primarily on Acropora cervicornis or A. palmata , the capacity to rapidly test and select for a variety of species using these stress assays and include them in nurseries and restoration operations is key to securing biologically diverse and functional reefs ( Baums et al., 2019 ). Moreover, thermotolerance research is often limited to specific areas with established laboratories and experimental systems, making it difficult to draw general, region-wide conclusions about thermal resilience, especially when methodologies differ between studies ( Grottoli et al., 2021 ). Conducting these standardized studies across multiple locations where restoration programs are already in place will help to identify consistent tolerance mechanisms across species and populations, including those influenced by site-specific conditions. The established network of coral nurseries and restoration sites of Iberostar across the Caribbean, together with the internal team of scientists, restoration practitioners and operation managers, constitutes an ideal framework for restoration-applied thermotolerance research. Applying thermal stress assays information into a multinational restoration program in a cost-effective and logistically efficient manner is particularly promising for the advancement of restoration science and its application ( Ferse et al., 2021 ), and could help accelerate and expand the scale of restoration efforts that are currently limited in scope considering the vast area of reefs requiring restoration across the Caribbean.

Caribbean reefs have a long history of environmental threats and degradation that are rapidly intensifying. Addressing the main causes of this degradation through the reduction of greenhouse gas emissions and the sustainable use of fisheries, among other solutions, is crucial to bring hope to these extremely important ecosystems. Corals have some ability to adapt to change, however, due to the severity and rate of climate change, intervention through science-based restoration may be necessary to accelerate this process and keep up with our rapidly changing environment. Ecosystem restoration at scale is still a great challenge due to the many economic, logistical, and scientific barriers that this practice presents. The tourism sector has the potential to scale up reef restoration with a new role that goes beyond being a financial investor, but rather takes advantage of other strengths of this sector, such as the long-term presence and logistics resources in different destinations. The tourism sector can also directly participate in the scientific and operational processes of restoration and include the conservation of these natural assets as part of the business case in the face of climate change. Iberostar Hotels and Resorts’ restoration program across the Caribbean is presented as an example of this novel role. It includes a scientific program that is aligned with research priorities to solve the primary knowledge and implementation bottlenecks for efficient and scalable reef restoration practices. Among these priorities is the selection of thermotolerant corals for restoration, which can help to optimize and accelerate ecosystem resilience in the face of increasingly rapid climate change. We present a cost-effective approach to identify and select heat tolerant corals for restoration through the first use of the Coral Bleaching Automated Stress System (CBASS; Voolstra et al., 2020 ; Evensen et al., 2021 ) in Latin America and the Latin American Caribbean. Novel solutions, collaborations, and the participation of diverse sectors and actors, such as the tourism sector presented herein, are crucial to push the boundaries of science and accelerate reef restoration efforts before Caribbean reefs are pushed past the point of no return.

Author contributions

MB-P, NRE, CC-U, JC-T, DJB, VG, EH and MKM conceived the manuscript. MB-P, NE, CC-U, JC-T wrote the initial draft. All authors reviewed and edited the article and approved the submitted version.

This work was funded by Iberostar Group through its Wave of Change initiative.

Acknowledgments

The authors would like to thank Iberostar Group and the Department of Biological Sciences at Old Dominion University for making possible the collaboration. Research work was possible thanks to the help of Iberostar hotel managers and maintenance team employees who arranged an optimal space to set up and conduct the experiments; the dive center Dressel Divers, who supported diving operations; and the assistance of both scientists from the National Polytechnical Institute Research and Advanced Studies Center (Cinvestav) and Iberostar marine biologist interns from the National Autonomous University of Mexico (UNAM). Handling of species and development of research activities were possible thanks to the alliance Iberostar-Cinvestav.

Conflict of interest

Authors MB-P, CC-U, JC-T, VG, EH, MKM were employed by the company Iberostar Hotels and Resorts.

The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Abelson A. (2006). Artificial reefs vs coral transplantation as restoration tools for mitigating coral reef deterioration: benefits, concerns and proposed guidelines. B. Mar. Sci. 78 (1), 151–159.

Google Scholar

Albright R., Langdon C. (2011). Ocean acidification impacts multiple early life history processes of the Caribbean coral porites astreoides. Glob. Change Biol. 17 (7), 2478–2487. doi: 10.1111/j.1365-2486.2011.02404.x

CrossRef Full Text | Google Scholar

Anthony K. R. N., Marshall P. A., Abdullah A., Beeden R., Bergh C., Black R., et al. (2014). Operationalising resilience for adaptive coral reef management under global environmental change. Glob. Change Biol. 21, 48–61. doi: 10.1111/gcb.12700

Arias-González J. E., Rivera-Sosa A., Zaldívar-Rae J., Alva-Basurto C., Cortés-Useche C. (2016). “The animal forest and its socio-ecological connections to land and coastal ecosystems,” in Marine animal forests . Eds. Rossi S., Bramanti L., Gori A., Orejas C. (Springer Switzerland: Cham: Springer), 1209–1240. doi: 10.1007/978-3-319-17001-5_33-1

Aronson R., Bruckner A., Moore J., Precht B., Weil. E. (2008). Acropora cervicornis (United Kingdom: The IUCN Red List of Threatened Species 2008). doi: 10.2305/IUCN.UK.2008.RLTS.T133381A3716457.en

Baker A. C., Glynn P. W., Riegl B. (2008). Climate change and coral reef bleaching: An ecological assessment of long-term impacts, recovery trends and future outlook. Estuar. Coast. Shelf. Sci. 80 (4), 435–471. doi: 10.1016/j.ecss.2008.09.003

Baums I. B., Baker A. C., Davies S. W., Grottoli A. G., Kenkel C. D., Kitchen S. A., et al. (2019). Considerations for maximizing the adaptive potential of restored coral populations in the western Atlantic. Ecol. Applic. 29 (8), 1–23. doi: 10.1002/eap.1978

Bayraktarov E., Banaszak A., Maya P. H. M., Kleypas J., Arias-Gonzalez J. E., Blanco M., et al. (2020). Coral reef restoration efforts in Latin American countries and territories. PloS One 15 (8), 1–19. doi: 10.1371/journal.pone.0228477

Beyer H. L., Kennedy E. V., Beger M., Chen C. A., Cinner J. E., Darling E. S., et al. (2018). Risk-sensitive planning for conserving coral reefs under rapid climate change. Conserv. Lett. 11 (6), 1–10. doi: 10.1111/conl.12587

Boström-Einarsson L., Babcock R. C., Bayraktarov E., Ceccarelli D., Cook N., Fersel S. C. A., et al. (2020). Coral restoration–a systematic review of current methods, successes, failures and future directions. PloS One 15 (1), 1–24. doi: 10.1371/journal.pone.0226631

Calle-Triviño J., Cortés-Useche C., Sellares R., Arias-González J. E. (2018). Assisted fertilization of threatened staghorn coral to complement the restoration of nurseries in southeastern Dominican Republic. Reg. Stud. Mar. Sci. 18, 129–134. doi: 10.1016/j.rsma.2018.02.002

Calle-Triviño J., Muñiz-Castillo A. I., Cortés-Useche C., Morikawa M., Sellares- Blasco R., Arias-González J. E. (2021). Approach to the functional importance of acropora cervicornis in outplanting sites in the Dominican Republic. Front. Mar. Sci. 8, 1–21. doi: 10.3389/fmars.2021.668325

PubMed Abstract | CrossRef Full Text | Google Scholar

Calle-Triviño J., Rivera-Madrid R., León-Pech M. G., Cortés-Useche C., Sellares-Blasco R. I., Aguilar-Espinosa M., et al. (2020). Assessing and genotyping threatened staghorn coral acropora cervicornis nurseries during restoration in southeast Dominican republic. PeerJ 8. doi: 10.7717/peerj.8863

Caruso C., Hughes K., Drury C. (2021). Selecting heat-tolerant corals for proactive reef restoration. Front. Mar. Sci. 8. doi: 10.3389/fmars.2021.632027

Chamberland V. F., Snowden S., Marhaver K. L., Petersen D., Vermeij M. J. A. (2015). Restoration of critically endangered elkhorn coral (Acropora palmata) populations using larvae reared from wild-caught gametes. Glob. Ecol. Conserv. 4, 526–537. doi: 10.1016/j.gecco.2015.10.005

Cinner J. E., Huchery C., MacNeil M. A., Graham N. A., McClanahan T. R., Maina J., et al. (2016). Bright spots among the world’s coral reefs. Nature 535 (7612), 416–419. doi: 10.1038/nature18607

Claudet J., Bopp L., Cheung W. W. L., Devillers R., Escobar-Briones E., Haugan P., et al. (2019). A roadmap for using the UN decade for ocean science for sustainable development in support of science, policy, and action. One Earth 2 (1), 34–42. doi: 10.1016/j.oneear.2019.10.012

Cortés-Useche C., Hernández-Delgado E. A., Calle-Triviño J., Sellares Blasco R., Galván V., Arias-González J. E. (2021). Conservation actions and ecological context: Optimizing coral reef local management in the Dominican Republic. PeerJ 9, e10925. doi: 10.7717/peerj.10925

Cortés-Useche C., Muñiz-Castillo A. I., Calle-Triviño J., Yathiraj R., Arias-González J. E. (2019). Reef condition and protection of coral diversity and evolutionary history in the marine protected areas of southeastern Dominican Republic. Reg. Stud. Mar. Sci. 32, 100893. doi: 10.1016/j.rsma.2019.100893

Cortés-Useche C., Reyes-Gamboa W., Cabrera-Pérez J. L., Calle-Triviño J., Cerón-Flores A., Raigoza-Figueras R., et al. (2021). Capture, culture and release of postlarvae fishes: proof-of-concept as a tool approach to support reef management. Front. Mar. Sci. 8. doi: 10.3389/fmars.2021.718526

Cramer K. L., Donovan M. K., Jackson J. B., Greenstein B. J., Korpanty C. A., Cook G. M., et al. (2021). The transformation of Caribbean coral communities since humans. Ecol. Evol. 11 (15), 10098–10118. doi: 10.1002/ece3.7808

Cramer K. L., Jackson J. B., Donovan M. K., Greenstein B. J., Korpanty C. A., Cook G. M., et al. (2020). Widespread loss of Caribbean acroporid corals was underway before coral bleaching and disease outbreaks. Sci. Adv. 6 (17), 1–11. doi: 10.1126/sciadv.aax9395

Cunning R., Parker K. E., Johnson-Sapp K., Karp R. F., Wen A. D., Williamson O. M., et al. (2021). Census of heat tolerance among florida’s threatened staghorn corals finds resilient individuals throughout existing nursery populations. Proc. R. Soc B. 288 (1961), 1–10. doi: 10.1098/rspb.2021.1613

Drury C., Lirman D. (2021). Genotype by environment interactions in coral bleaching. Proc. R. Soc B. 288 (1946), 1–8. doi: 10.1098/rspb.2021.0177

Drury C., Manzello D., Lirman D. (2017). Genotype and local environment dynamically influence growth, disturbance response and survivorship in the threatened coral, acropora cervicornis. PloS One 12 (3), 1–21. doi: 10.1371/journal.pone.0174000

Eakin C. M., Morgan J. A., Heron S. F., Smith T. B., Liu G., Alvarez-Filip L., et al (2010). Caribbean corals in crisis: Record thermal stress, bleaching, and mortality in 2005. PloS One 5 (11). doi: 10.1371/journal.pone.0013969.

Edwards A. (2010). Reef rehabilitation manual. coral reef targeted research and capacity building for management. St. Lucia. Aust. , 166.

Evensen N. R., Fine M., Perna G., Voolstra C. R., Barshis D. J. (2021). Remarkably high and consistent tolerance of a red Sea coral to acute and chronic thermal stress exposures. Limnol. Oceanogr. 66 (5), 1718–1729. doi: 10.1002/lno.11715

Evensen N. R., Voolstra C. R., Fine M., Perna G., Buitrago-López C., Cárdenas A., et al. (2022). Empirically derived thermal thresholds of four coral species along the red Sea using a portable and standardized experimental approach. Coral. Reefs. 41 (2), 1–14. doi: 10.1007/s00338-022-02233-y

Ferse S. C., Hein M. Y., Rölfer L. (2021). A survey of current trends and suggested future directions in coral transplantation for reef restoration. PloS One 16 (5), 1–21. doi: 10.1371/journal.pone.0249966

Gladfelter W. B. (1982). White-band disease in acropora palmata: implications for the structure and growth of shallow reefs. Bull. Mar. Sci. 32, 639–643.

Grottoli A. G., Rodriguez L. J., Palardy J. E. (2006). Heterotrophic plasticity and resilience in bleached corals. Nature 440, 1186–1189. doi: 10.1038/nature04565

Grottoli A. G., Toonen R. J., van Woesik R., Vega Thurber R., Warner M. E., McLachlan R. H., et al. (2021). Increasing comparability among coral bleaching experiments. Ecol. Appl. 31 (4), 1–17. doi: 10.1002/eap.2262

Guest J. R., Low J., Tun K., Wilson B., Ng C., Raingeard D., et al. (2016). Coral community response to bleaching on a highly disturbed reef. Sci. Rep. 6 (1), 1–10. doi: 10.1038/srep20717

Hein M. Y., Couture F., Scott C. M. (2018). “Ecotourism and coral reef restoration: case studies from Thailand and the Maldives,” in Coral reefs: Tourism, conservation and management . Eds. Prideaux B., Pabel A.(Oxford: Routledge: Taylor & Francis), 137–150. doi: 10.4324/9781315537320-10

Hein M. Y., McLeod I. M., Shaver E. C., Vardi T., Pioch S., Boström-Einarsson L., et al. (2020). Coral reef restoration as a strategy to improve ecosystem services a guide to coral restoration methods (Nairobi: United Nations Environment Program).

Hughes T. P., Anderson K. D., Connolly S. R., Heron S. F., Kerry J. T., Lough J. M., et al. (2018). Spatial and temporal patterns of mass bleaching of corals in the anthropocene. Science 359, 80–83. doi: 10.1126/science.aan8048

Hughes T. P., Kerry J. T., Alvarez-Noriega M., Alvarez-Romero J. G., Anderson K. D., Babcock R. C., et al. (2017). Global warming and recurrent mass bleaching of corals. Nature 543, 373–377. doi: 10.1038/nature22901

Hughes T. P., Connell J. H.. (1999). Multiple stressors on coral reefs: A long–term perspective. Limnol. Oceanogr. 44 (3part2), 932–940. doi: 10.4319/lo.1999.44.3_part_2.0932

Gardner T. A., Côté I. M., Gill J. A., Grant A., Watkinson A. R. (2005). Hurricanes and Caribbean coral reefs: impacts, recovery patterns, and role in long‐term decline. Ecology 86 (4), 174–184. doi: 10.1890/04-0141

Hughes T. P.. (1994). Catastrophes, phase shifts, and large-scale degradation of a Caribbean coral reef. Science 265 (5178), 1547–1551. doi: 10.1126/science.265.5178.1547

Kenkel C. D., Almanza A. T., Matz M. V. (2015). Fine-scale environmental specialization of reef-building corals might be limiting reef recovery in the Florida keys. Ecol 96 (12), 3197–3212. doi: 10.1890/14-2297.1

Kenkel C. D., Goodbody-Gringley G., Caillaud D., Davies S. W., Bartels E., Matz M. V. (2013). Evidence for a host role in thermotolerance divergence between populations of the mustard hill coral (Porites astreoides) from different reef environments. Mol. Ecol. 22 (16), 4335–4348. doi: 10.1111/mec.12391

Kenkel C., Matz M. (2017). Gene expression plasticity as a mechanism of coral adaptation to a variable environment. Nat. Ecol. Evol. 1, 14. doi: 10.1038/s41559-016-0014

Klepac C. N., Barshis D. J. (2020). Reduced thermal tolerance of massive coral species in a highly variable environment. Proc. R. Soc B. 287, 1–9. doi: 10.1098/rspb.2020.1379

Lang J. C., Marks K. W., Kramer P. A., Kramer P. R., Ginsburg R. N. (2011). AGRRA Protocols. Version 5.5. The Atlantic and Gulf Rapid Reef Assessment (AGRRA) Program .

Lessios H. A., Robertson D. R., Cubit J. D. (1984). Spread of diadema mass mortality through the caribbean. Science 226 (4672), 335–337. doi: 10.1126/science.226.4672.335

Lirman D., Gracias N. R., Gintert B. E., Gleason A. C.R., Reid R. P., Negahdaripour S., et al (2007). Development and application of a video-mosaic survey technology to document the status of coral reef communities. Environ. Monit. Assess. 125 (1) 59–73. doi: 10.1007/s10661-006-9239-0

Lirman D., Schopmeyer S., Galvan V., Drury C., Baker A. C. (2014). Growth dynamics of the threatened Caribbean staghorn coral acropora cervicornis: Influence of host genotype, symbiont identity, colony size, and environmental setting. PloS One 9 (9), 1–9. doi: 10.1371/journal.pone.0107253

Loya Y., Sakai K., Yamazato K., Nakano Y., Sambali H., Van Woesik R. (2001). Coral bleaching: the winners and the losers. Ecol. Lett. 4 (2), 122–131. doi: 10.1046/j.1461-0248.2001.00203.x

Maliao R. J., Turingan R. G., Lin J. (2008). Phase-shift in coral reef communities in the florida keys national marine sanctuary (FKNMS), USA. Mar. Biol. 154 (5), 841–853. doi: 10.1007/s00227-008-0977-0

Manzello D. P. (2015). Rapid recent warming of coral reefs in the Florida keys. Sci. Rep. 5 (1), 1–10. doi: 10.1038/srep16762

Marshall P. A., Baird A. H. (2000). Bleaching of corals on the great barrier reef: differential susceptibilities among taxa. Coral. Reefs. 19 (2), 155–163. doi: 10.1007/s003380000086

McClanahan T. R., Darling E. S., Maina J. M., Muthiga N. A., Leblond J., Arthur R., et al. (2020). Highly variable taxa-specific coral bleaching responses to thermal stresses. Mar. Ecol. Prog. Ser. 648, 135–151. doi: 10.3354/meps13402

McWilliams J. P., Côté I. M., Gill J. A., Sutherland W. J., Watkinson A. R. (2005). Accelerating impacts of temperature-induced coral bleaching in the Caribbean. Ecology 86 (8), 2055–2060. doi: 10.1890/04-1657

Morikawa M. K., Palumbi S. R. (2019). Using naturally occurring climate resilient corals to construct bleaching-resistant nurseries. Proc. Natl. Acad. Sci. 116, 1–6. doi: 10.1073/pnas.1721415116

Mumby P. J., Hastings A., Edwards H. J. (2007). Thresholds and the resilience of Caribbean coral reefs. Nature 450 (7166), 98–101. doi: 10.1038/nature06252

Page C. (2013). Reskinning a reef: Mote Marine Lab scientists explore a new approach to reef restoration. In B Benthic Ecology Meeting .

Page C., Vaughan D. (2014). The cultivation of massive corals using “micro-fragmentaion” for the ‘reskinning’ of degraded coral reefs. Coral Magazine 10 (5), 72–80.

Palumbi S. R., Barshis D. J., Traylor-Knowles N., Bay R. A. (2014). Mechanisms of reef coral resistance to future climate change. Science 344, 895–898. doi: 10.1126/science.1251336

Pratchett M. S., Hoey A. S., Wilson S. K. (2014). Reef degradation and the loss of critical ecosystem goods and services provided by coral reef fishes. Curr. Opin. Environ. Sustain. 7, 37–43. doi: 10.1016/j.cosust.2013.11.022

Precht W. F., Gintert B. E., Robbart M. L., Fura R., Van Woesik R. (2016). Unprecedented disease-related coral mortality in southeastern Florida. Sci. Rep. 6 (1), 1–11. doi: 10.1038/srep31374

Quigley K. M., Hein M., Suggett D. J. (2022). Translating the ten golden rules of reforestation for coral reef restoration. Cons. Biol 36 (4), 1–8. doi: 10.1111/cobi.13890

Rinkevich B. (2015). Climate change and active reef restoration–ways of constructing the “reefs of tomorrow. J. Mar. Sci. Eng. 3 (1), 111–127. doi: 10.3390/jmse3010111

Roff G. (2021). Evolutionary history drives biogeographic patterns of coral reef resilience. BioScience 71 (1), 26–39. doi: 10.1093/biosci/biaa145

Schmidt-Roach S., Duarte C., Hauser C. A., Aranda M. (2020). Beyond reef restoration: next-generation techniques for coral gardening, landscaping, and outreach. Front. Mar. Sci. 7. doi: 10.3389/fmars.2020.00672

Schopmeyer S. A., Lirman D., Bertels E., Gilliem D. S., Goergen E. A., Griffin S. P., et al. (2017). Regional restoration benchmarks for acropora cervicornis. Coral. Reefs. 36, 1047–1057. doi: 10.1007/s00338-017-1596-3

Singh T., Iijima M., Yasumoto K., Sakai K. (2019). Effects of moderate thermal anomalies on acropora corals around sesoko island, Okinawa. PloS One 14 (1), 1–20. doi: 10.7717/peerj.8138

Spalding M., Burke L., Wood S. A., Ashpole J., Hutchison J., Zu Ermgassen P., et al (2017). Mapping the global value and distribution of coral reef tourism. Mar. Policy 82, 104–113. doi: 10.1016/j.marpol.2017.05.014

Suggett D. J., van Oppen M. J. (2022). Horizon scan of rapidly advancing coral restoration approaches for 21st century reef management. Emerg. Top. Life Sci. 6 (1), 125–136. doi: 10.1042/ETLS20210240

Thomas L., López E. H., Morikawa M. K., Palumbi S. R. (2022). Transcriptomic resilience, symbiont shuffling, and vulnerability to recurrent bleaching in reef–building corals. Mol. Ecol. 28 (14), 3371–3382. doi: 10.1111/mec.15143

Vardi T., Hoot W. C., Levy J., Shaver E., Winters R. S., Banaszak A. T., et al. (2021). Six priorities to advance the science and practice of coral reef restoration worldwide. Restor. Ecol. 29 (8), 1–7. doi: 10.1111/rec.13498

Voolstra C. R., Buitrago-López C., Perna G., Cárdenas A., Hume B. C., Rädecker N., et al. (2020). Standardized short-term acute heat stress assays resolve historical differences in coral thermotolerance across microhabitat reef sites. Glob. Change Biol. 26 (8), 4328–4343. doi: 10.1111/gcb.15148

Voolstra C. R., Valenzuela J. J., Turkarslan S., Cárdenas A., Hume B. C., Perna G., et al. (2021). Contrasting heat stress response patterns of coral holobionts across the Red Sea suggest distinct mechanisms of thermal tolerance. Mol. Ecol. 30 (18), 4466–480. doi: 10.1111/mec.16064

Waltham N. J., Elliott M., Lee S. Y., Lovelock C., Duarte C. M., Buelow C., et al. (2020). UN Decade on ecosystem restoration 2021–2030—what chance for success in restoring coastal ecosystems? Front. Mar. Sci. 7. doi: 10.3389/fmars.2020.00071

Wilkinson C. R., Souter D. (2008). Status of caribbean coral reefs after bleaching and hurricanes in 2005. global coral reef monitoring network and reef and rainforest research center (Townsville: Global Coral Reef Monitoring Network).

Young C. N., Schopmeyer S. A., Lirman D. (2012). A review of reef restoration and coral propagation using the threatened genus acropora in the Caribbean and Western Atlantic. Bull. Mar. Sci. 88 (4), 1075–1098. doi: 10.5343/bms.2011.1143

Keywords: reef restoration, Caribbean, private sector, sustainable tourism, coral bleaching, thermal stress, coral bleaching automated stress system (CBASS)

Citation: Blanco-Pimentel M, Evensen NR, Cortés-Useche C, Calle-Triviño J, Barshis DJ, Galván V, Harms E and Morikawa MK (2022) All-inclusive coral reef restoration: How the tourism sector can boost restoration efforts in the caribbean. Front. Mar. Sci. 9:931302. doi: 10.3389/fmars.2022.931302

Received: 28 April 2022; Accepted: 01 August 2022; Published: 24 August 2022.

Reviewed by:

Copyright © 2022 Blanco-Pimentel, Evensen, Cortés-Useche, Calle-Triviño, Barshis, Galván, Harms and Morikawa. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Macarena Blanco-Pimentel, [email protected]

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

An official website of the United States government

Here’s how you know

Official websites use .gov A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS A lock ( Lock A locked padlock ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

JavaScript appears to be disabled on this computer. Please click here to see any active alerts .

Basic Information about Coral Reefs

• What are coral reefs?
• Where are coral reefs found?
• Why are coral reefs important?

What are Coral Reefs?

Coral reef ecosystems are intricate and diverse collections of species that interact with each other and the physical environment. Coral is a class of colonial animal that is related to hydroids, jellyfish, and sea anemones.

Stony corals, a type of coral characterized by their hard skeleton, are the bedrock of the reef. Stony coral colonies are composed of hundreds of thousands of individual living polyps. Polyps are capable of drawing dissolved calcium from seawater, and solidifying it into a hard mineral (calcium carbonate) structure that serves as their skeletal support. When you look at a coral colony, only the thin layer on its surface is live coral; the mass beneath is the calcium carbonate skeleton that may be decades old.

The slow growth of polyps and expansion of the hard skeletal structures build up the permanent coral reef structure over time.

Polyps of reef-building corals contain microscopic algae called zooxanthellae , which exist with the animal in a symbiotic relationship. The coral polyps (animals) provide the algae (plants) a home, and in exchange the algae provide the polyps with food they generate through photosynthesis. Because photosynthesis requires sunlight, most reef-building corals live in clear, shallow waters that are penetrated by sunlight. The algae also give a coral its color; coral polyps are actually transparent, so the color of the algae inside the polyps show through.  When corals are stressed, they expel these algal symbionts through a process known as coral bleaching. Corals also face serious risk of diseases.

Coral reefs provide habitat for a large variety of marine life, including various sponges, oysters, clams, crabs, sea stars, sea urchins, and many species of fish. Coral reefs are also linked ecologically to nearby seagrass, mangrove, and mudflat communities. One of the reasons that coral reefs are so highly valued is because they serve as a center of activity for marine life.

Not all corals on the reef are stony corals.

• Hydrocorals , or fire coral, are reef-building hydroids that have a hard calcareous exoskeleton and stinging cells that can cause a burning sensation when touched.
• Octocorals , or ‘soft’ corals, include sea fans and sea whips, which grow more like fleshy plants and do not form calcium carbonate skeletal structures.
• Antipatharians , or black corals, are another type of branching ‘soft’ coral.

Some soft corals have zooxanthellae to acquire food and energy, but others, such as black corals, exist without this symbiotic relationship.

Where are Coral Reefs Found?

Corals can be found throughout the world’s oceans, in both shallow and deep water. However, the reef-building corals that rely on a symbiotic relationship with algae need shallow, clear water, allowing light penetration for photosynthesis. Stony corals also require tropical or sub-tropical temperatures, which exist in a band between 30 degrees north and south latitudes.

• Puerto Rico,
• U.S. Virgin Islands ,
• Hawaiʻi , and
• Guam , American Samoa , and the Commonwealth of the Northern Mariana Islands .

There are also coral reefs 100 miles offshore of Texas and Louisiana in the Gulf of Mexico , living on the tops of geologic ‘mesas’.

Why are Coral Reefs Important?

Coral reefs hold enormous ecological, economic, and cultural value to hundreds of millions of people around the world, providing valuable ecosystem services, including nutrition, economic security, and protection from natural disasters. Coral reefs are among the most biologically diverse and valuable ecosystems on Earth. An estimated 25 percent of all marine life, including over 4,000 species of fish, are dependent on coral reefs at some point in their life cycle.

• Habitat, feeding, spawning, and nursery grounds for over 1 million aquatic species, including commercially harvested fish species.
• Food for people living near coral reefs, especially on small islands.
• Recreation and tourism opportunities, such as fishing, scuba diving, and snorkeling, which contribute billions of dollars to local economies.
• Protection of coastal infrastructure and prevention of loss of life from storms, tsunamis, floods, and erosion.
• Sources of new medicines that can be used to treat diseases and other health problems.

All of the services provided by coral reefs translate into tremendous economic worth. By one estimate, the total net benefit per year of the world’s coral reefs is $29.8 billion. Tourism and recreation account for $9.6 billion of this amount, coastal protection for $9.0 billion, fisheries for $5.7 billion, and biodiversity, representing the dependence of many different marine species on the reef structure, for $5.5 billion (Cesar, Burke and Pet-Soede, 2003).

In the U.S., the U.S. Geological Survey estimates that  coral reefs in the Atlantic, Caribbean and Pacific Islands regions help generate billions in annual tourism dollars, yield ~$100 million (annually) in commercial fisheries and protect tens of thousands of lives and billions in property and economic activity from flooding and erosion.

• Coral Reefs Home
• America's Coral Reefs
• Threats to Coral Reefs
• Additional Resources
• What EPA is Doing
• What You Can Do
• EPA's Coral Reef Partners

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

Recreational activity is one of the joys in life that so many people share. Various types of recreation get people outside in all conditions from the 10 o F New England winter weather to the hot beaches of a Caribbean island. Some tropical island activities include: boating, kayaking, scuba diving, snorkeling, sailing, wind surfing, and wake boarding- but they all have one thing in common, that is they are located in the ocean. Although some take place in deeper water, many of these activities are performed in shallow waters full of coral reef habitats. We know how fragile and important these reefs are and we also know how easily us humans have caused damage to them. Coral reef ecosystems are among the most biologically diverse and economically valuable ecosystems on Earth. Worldwide precious coral reefs attract millions of tourists annually and yield a significant economic benefit to those countries and regions where they are located. According to the National Oceanic and Atmospheric Administration (NOAA ), recreation and tourism account for $9.6 billion of the total global net profit of coral reefs. This large amount of revenue generated is being threatened by the degradation of coral reefs.

Little Venice quay flooded with tourists. Mykonos island. Cyclades, Agean Sea, Greece. Photo by Mstyslav Chernov. [CC BY-SA 3.0]

Most tourism in natural areas today is not ecotourism and is not, therefore, sustainable. Specifically,  ecotourism possesses the following characteristics :

• Conscientious, low-impact visitor behavior
• Sensitivity towards, and appreciation of, local cultures and biodiversity
• Support for local conservation efforts
• Sustainable benefits to local communities
• Local participation in decision-making
• Educational components for both the traveler and local communities

What is ecotourism? Photo by Ron Mader via Flikr. [CC BY-SA 2.0]

“Tourism will never be completely sustainable , as every industry has impacts. However, it’s important to know if the revenue created from tourism is reinvested correctly in order to benefit the coral reefs and build a sustainable future. For ecotourism to be sustainable, companies must take responsibility and allocate revenue it generates from its eco-attractions into the protection of reefs instead of further investing in tourist structures and attractions that have negative impacts on the health of these ecosystems.”

Recreational activities can harm coral reefs through:

• Breakage of coral colonies and tissue damage from direct contact such as walking, touching, kicking, standing, or gear contact
• Breakage or overturning of coral colonies and tissue damage from boat anchors
• Changes in marine life behavior from feeding or harassment by humans
• Water pollution
• Invasive species
• Trash and debris deposited in the marine environment

There are lessons to learn from the ecological destruction in Australia, Hawaii, Indonesia and other Pacific Islands where recreational activities are high in the bays of resort-filled areas and multiple-use marine parks.

In a study in Australia, activities such as diving, snorkeling, ski jets, and motor boats with surfing skis had high impacts on coral reef ecosystems. These activities can cause direct damage to the corals and increase pollution in the water. Surfing had less negative impact as it is superficial. 

Some activities and their impacts are listed below.

[material below 1-4 is copied from How Does Tourism Affect Coral Reefs? ]:

1.) Scuba Diving and Snorkeling

While most diving and snorkeling activities have little physical impact on coral reefs, physical damages to corals can and do occur when people stand on, walk on, kick, touch, trample, and when their equipment contacts corals. Coral colonies can be broken and coral tissues can be damaged when such activities occur. Divers and snorkelers can also kick up sediment that is damaging to coral reefs.

2.) Boating and Anchors

Boats grounding in coral reef habitat can damage corals, as can anchors. Anchors can cause a great deal of coral breakage and fragmentation, particularly from large boats like freighters and cruise ships. Heavy chains from large ships can break or dislodge corals. These damages to corals can last for many years.

Anchoring can also damage the habitats near reefs such as seagrasses that serve as nurseries and habitats for the juveniles of different coral reef organisms. Marinas may inappropriately dispose of oils and paint residues, polluting local waters, and additional pollution may occur during fueling.

3.) Fishing and Seafood Consumption

An abundance of tourist fishing and consumption of local fish stocks may lead to overexploitation and competition with local fishers. Inappropriate fishing techniques such as  bottom trawling  can cause physical damage to reefs.

4.) Cruises and Tour Boats

These vessels can cause physical damage to reefs through anchoring and grounding, as well as through the release of gray water and human waste into coral reef habitat. Chemicals added to paint used on boats and fishnets that are intended to discourage the growth of marine organisms can also cause pollution in coral reef waters.

The variety of marine life and protected beaches supported by coral reefs provide beautiful sights for sightseers, sunbathers, snorkelers. Healthy reefs support local  and global economies. Through the tourism industry and fisheries, coral reefs generate billions of dollars, and millions of jobs, in more than 100 countries around the world. Studies show that on average, countries with coral reef industries derive more than half of their gross national product from them. A good example can be found in  Bonaire,  a small Caribbean island. Bonaire earns about  $23 million (USD) annually from coral reef activities , yet managing its marine park costs less than $1 million per year.  A study conducted in 2002  estimated the value of coral reefs at $10 billion, with direct economic benefits of $360 million per year. For residents of coral reef areas who depend on income from tourism, reef destruction creates a significant loss of employment in the tourism, marine recreation, and sport fishing industries.

As we all know, coral reefs are undergoing major stress-related side effects because of human impacts. Through over-use, direct damage and ill-considered tourist operations, the World Wildlife Fund predicts that 24% of the world’s reefs are under imminent risk  of collapse through human pressures; and a further 26% are under a longer term threat of collapse. Another significant anthropogenic problem facing coral reefs is sedimentation.  Sedimentation (losing soil from upland areas) is an extremely important cause of coral reef destruction . Coastal construction and shoreline development (back to the ecotourism concept) often result in heavy sediment loading. Watersheds cleared of their forests and other vegetation cover is vulnerable to erosion and flooding, resulting in increased levels of sediments reaching the reefs. Excessive sedimentation also exceeds the clearing capacity of some filter feeders and smothers the substrate. It reduces light penetration and can alter the vertical distribution of plants and animals on reefs. Sediments can also absorb and transport other pollutants.

When  tourists  accidently touch, pollute or break off parts of the reef, corals experience stress. The coral organisms try to fight off the intrusion, but this process often leads to coral bleaching—when corals react in a stressed way to expel the brightly colored algae that live in them this in turn, starves themselves and eventually become completely white.  Once corals are bleached , they die and can no longer contribute to the biodiversity of the reef community. Since the disruption of one ocean system impacts all the others, sea grass and mangroves—shallow-water plant species vital to the health of the marine ecosystem—are also threatened by coral stress. Many of these events of accidental coral destruction are caused by recreational activities.

One study  examined diver behavior at several important coral reef dive locations within the Philippines and also assessed how diver characteristics and dive operator compliance with an environmentally responsible diving program, known as the Green Fins approach, affected reef contacts. The role of dive supervision was assessed by recording dive guide interventions underwater, and how this was affected by dive group size.  Of the 100 recreational divers followed, 88 % made contact with the reef at least once per dive . Divers from operators with high levels of compliance with the  Green Fins program  exhibited significantly lower reef contact rates than those from dive operators with low levels of compliance.

Although it’s difficult for an individual to stop the entire coral reef dilemma  it’s easy to take small but powerful steps  in the right direction.

Some of these steps include:

• Don’t touch living coral and don’t pick up wildlife for souvenirs, including shells, coral rubble and plants.
• Be conscious of what you bring with you, for example, reusable water bottles instead of plastic bottles and a backpack for your trash in case there isn’t an area nearby to dispose of waste properly.
• Take the bus instead of a car, and if possible, do your research on the hotels or hostels where you stay.
• Try to stay at hotels that are environmentally friendly. Many coastal hotels dump their graywater—wastewater from laundry, cooking and household sinks—into the ocean, contributing to sedimentation and the contamination of coral reefs.

So, the message of this post is to be aware of corals and precious ecosystems when recreating! Also, try to vacation more sustainably by researching and traveling more eco-friendly. Some places that offer eco-tourism travel are  green loons . Travel Tips for eco-traveling can be found below.

The information in this chapter in thanks to content contributions from Audrey Boraski .

A Student's Guide to Tropical Marine Biology Copyright © by by Keene State College Students, BIO 381 Tropical Marine Biology is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License , except where otherwise noted.

Share This Book

• Show search

Caribbean Wide Impact in Coral Conservation

How Coral Innovation Hubs across the Caribbean are making a difference.

June 08, 2024

Coral Touching the Sky Elkhorn coral growing in a coral nursery tree © MSJ Visuals

"You should have seen it 10 years ago", the lingering words echo in a Bahamian youth's mouth as he speaks about how coral reefs in The Bahamas have degraded over time. But this trend is not exclusive to The Bahamas. Across the Caribbean, coral reefs have suffered due to global and local stressors. Massive, region-wide decline of corals across the entire Caribbean basin have been reported, with the average stony coral cover on reefs being reduced by 80% (Gardner et al. 2003).

But why are coral reefs important? An estimated 25% of all marine life, including over 4,000 species of fish, are dependent on coral reefs at some point in their life cycle. Healthy coral reefs provide habitat, feeding, spawning and nursery grounds for over 1 million aquatic species, including commercially harvested fish species. And as the effects of climate change continue to mount, their ability to reduce wave energy and erosion is a critical line of defense for coastal regions as storm intensities increase. Moreover, their economic impacts for fisheries and tourism are in the billions for the Caribbean region and valued at $375 billion per year worldwide.

To protect and restore coral reefs, TNC is guiding effective marine management and innovating ways to accelerate coral reproduction and reef recovery. This multifaceted approach aims to restore the long-term health of coral reefs, increase their resilience to a changing climate and address the threats that have caused their deterioration. Partnering with local organizations, institutions, communities and governments, we are shaping a brighter future for these vital ecosystems that benefit more than 44 million people across the Caribbean. To achieve these goals at scale, we have established three key Coral Innovation Hubs across the region in The Bahamas, US Virgin Islands and Dominican Republic.

Through state-of-the-art lab facilities and extensive coral nurseries at these Hubs, we’re developing techniques to breed significantly more corals for restoration, with greater survival rates. These techniques include larval propagation, which helps preserve coral genetic diversity and resilience, and microfragmentation, a process that dramatically stimulates coral growth.

In 2018 our first Coral Hub was established in The Bahamas at the Cape Eleuthera Institute in close collaboration with Perry Institute for Marine Science. Here, TNC and partners are working to increase the efficiency and effectiveness of facilitated sexual coral breeding and outplanting techniques. Hands-on education is offered to local students through field trips that include snorkeling to underwater coral nurseries and visits to the Institute’s research facility.

In 2023, the Hub reported more than 24 coral tree nurseries maintained with more than 1400 fragments , which makes this the biggest coral nursery in The Bahamas. Last year alone, over 600 new fragments were created from three new coral nursery sites, and over 434 corals were outplanted at four different outplanting sites across the area. In addition, over a million larvae of the important reef-building mountainous star cora l ( Orbicella faveolata ) were raised in the lab and over 191 fragments were collected from ocean-based nurseries.

The Nature Conservancy’s U.S. Virgin Islands Coral Innovation Hub is a land-based coral nursery and laboratory based at Estate Little Princess, on St. Croix. The Hub is dedicated to advancing coral restoration science in the Caribbean through cutting-edge research, innovative technologies and strategic partnerships. From coral restoration initiatives to community engagement programs, the Hub's multifaceted approach exemplifies collaboration and innovation to restore the long-term health effects of coral reef ecosystems. In 2024, it was designated as a Coral Reef Research Center (CRRC) by the National Oceanic and Atmospheric Administration’s (NOAA) Coral Reef Conservation Program

The TNC USVI Coral Innovation Hub has demonstrated exceptional skill and effectiveness at coral conservation techniques. In 2023, this Hub reported over 2,054,250 total coral embryos created and 1,023,000 embryos reared for settlement. Of the previous figure, 139,920 total coral individuals “settled” on the reef. A sample of the species outplanted include over 500 fragments of finger coral ( Porites porites ), over 1200 fragments of critically endangered elkhorn coral ( Acropora palmata ) and over 1500 symmetrical brain coral ( Pseudodiploria strigosa) from the 2023 spawning season.

Our Dominican Republic Coral Innovation Hub is jointly based at Grupo Puntacana Foundation’s (FGPC) Center for Marine Innovation with close collaboration with the NGO Fundacion Dominicana de Estudios Marinos (FUNDEMAR). Here, TNC and partners are advancing asexual coral reproduction and outplanting techniques, while offering local students hands-on education through field trips to the Hub’s lab facilities.

In 2023, this Hub reported creating over 3122 fragments from six different coral species in their terrestrial nursery. At their marine nurseries they house 40 structures focused on the critically endangered species staghorn coral ( Acropora cervicornis ). Over 800 fragments of critically endangered elkhorn coral ( Acropora palmata ) were produced from marine nurseries. More than 9.5 million coral embryos of seven different important coral species were also produced and from this figure over 500,000 coral individuals “settled ” and began to grow on the reef.

Soon FGPC and FUNDEMAR will have two new facilities to further advance coral and marine research with the latest and most innovative technologies. This infrastructure is partially funded by OceanKind and TNC, and we are looking forward to further scaling up our coral work in the Dominican Republic.

As Caribbean corals continue to face various threats, it’s more essential than ever to be able to replicate effective coral restoration measures across the region and scale up our efforts to defend and restore these critical creatures.

All these Hubs have made great impacts over the years regarding coral education and restoration; millions of coral fragments have been created of various coral species, tens of thousands of outplants have been placed into the ocean, thousands of locals and partners have been able to improve their knowledge on coral conservation methods and topics and countless hours have been spent researching these fascinating creatures.

However, coral restoration impacts are not just measured in storm energy dampening or species richness. They are measured in real-world effects for local populations. Reefs restored with transplanted corals quickly see improvements regarding the presence of marine biodiversity compared to reefs that are allowed to collapse. The return of endemic marine creatures to a reef not only signals a recovering ecosystem, but it gives hope for coastal communities who depend on reefs for their livelihoods.

By restoring coral reefs, we are investing in the future of our oceans and the well-being of coastal communities around the globe. The Nature Conservancy and partners have achieved so much in the region thus far—through continued collaboration and support, a healthier Caribbean for nature and people is within our reach.

We Can’t Save Nature Without You

Sign up to receive monthly conservation news and updates from the Caribbean.

Please provide a valid email address

You’ve already signed up with this email address. To review your email preferences, please visit nature.org/emailpreferences

We may have detected a typo. Please enter a valid email address (formatted as [email protected]). Did you mean to type ?

We are sorry, but there was a problem processing the reCAPTCHA response. Please contact us at [email protected] or try again later.

Our Valued Partners

Thank you for supporting our work and collaborating with us

TNC Participates in U.S. Coral Reef Task Force Meeting

Our teams in Puerto Rico and the USVI convened in beautiful St. Croix for the U.S. Coral Reef Task Force Meeting to discuss priorities for coral conservation.

CoralCarib—Advancing Coral Monitoring and Restoration

CoralCarib is a unique coral restoration project from TNC in the Caribbean designed to target key coral refugia areas in Cuba, Haiti, the Dominican Republic and Jamaica.

Reef Responsible

By raising awareness about the importance of making sustainable seafood choices, we are empowering communities to help protect the Caribbean's iconic and valuable coral reefs.

An official website of the United States government

Here’s how you know

Official websites use .gov A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS A lock ( Lock A locked padlock ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

• Education home
• About NOAA Education
• NOAA in your backyard: Alaska
• NOAA in your backyard: Caribbean
• NOAA in your backyard: Central
• NOAA in your backyard: Great Lakes
• NOAA in your backyard: Gulf of Mexico
• NOAA in your backyard: Mid-Atlantic
• NOAA in your backyard: Northeast
• NOAA in your backyard: Northwest
• NOAA in your backyard: Pacific Islands
• NOAA in your backyard: Southeast
• NOAA in your backyard: Southwest
• Educational mailing lists
• Jan-Mar 2024
• Oct-Dec 2023
• Jul-Sep 2023
• Apr-Jun 2023
• NOAA Sea to Sky: Education resource database
• Ocean acidification
• Ocean currents
• Ocean floor features
• Ocean pollution and marine debris
• El Niño and La Niña
• Space weather
• Weather observations
• Weather systems & patterns
• Carbon cycle
• Changing seasons
• Climate change impacts
• Climate data monitoring
• Aquatic food webs

Coral reef ecosystems

• Fisheries and seafood
• Life in an estuary
• Marine mammals
• Sea turtles
• Great Lakes ecoregion
• Water cycle
• Watersheds, flooding, and pollution
• Data resources for educators
• Education at home
• Elementary resources
• Hands-on science activities
• Special topics
• Conference resources
• About the education resource collections
• Conservation Service Corp Act Direct Hiring Authority
• Educator opportunities
• Grants & networks
• News and stories

Coral reefs are some of the most diverse ecosystems in the world. Coral polyps , the animals primarily responsible for building reefs, can take many forms: large reef building colonies, graceful flowing fans, and even small, solitary organisms. Thousands of species of corals have been discovered; some live in warm, shallow, tropical seas and others in the cold, dark depths of the ocean.

School in great numbers at Rapture Reef, French Frigate Shoals, Papahānaumokuākea National Marine Monument (Image credit: James Watt)

Coral reef diversity

Because of the diversity of life found in the habitats created by corals, reefs are often called the "rainforests of the sea." About 25% of the ocean's fish depend on healthy coral reefs. Fishes and other organisms shelter, find food, reproduce, and rear their young in the many nooks and crannies formed by corals. The Northwest Hawaiian Island coral reefs, which are part of the Papahānaumokuākea National Marine Monument , provide an example of the diversity of life associated with shallow-water reef ecosystems. This area supports more than 7,000 species of fishes, invertebrates, plants, sea turtles, birds, and marine mammals. Deep water reefs or mounds are less well known, but also support a wide array of sea life in a comparatively barren world .

In the early days of undersea research at NOAA, scientists needed to surface regularly when SCUBA diving to study coral reefs and other habitats. This slowed down their progress, making it difficult to conduct longer studies. All that changed with the introduction of the HYDROLAB.

Coral characteristics

Shallow water, reef-building corals have a symbiotic relationship with photosynthetic algae called zooxanthellae , which live in their tissues. The coral provides a protected environment and the compounds zooxanthellae need for photosynthesis. In return, the algae produce carbohydrates that the coral uses for food, as well as oxygen. The algae also help the coral remove waste. Since both partners benefit from association, this type of symbiosis is called mutualism.

Deep-sea corals live in much deeper or colder oceanic waters and lack zooxanthellae. Unlike their shallow water relatives, which rely heavily on photosynthesis to produce food, deep sea corals take in plankton and organic matter for much of their energy needs.

Benefits of coral reef ecosystems

Coral reefs protect coastlines from storms and erosion, provide jobs for local communities, and offer opportunities for recreation. They are also are a source of food and new medicines . Over half a billion people depend on reefs for food, income, and protection. Fishing, diving, and snorkeling on and near reefs add hundreds of millions of dollars to local businesses. The net economic value of the world’s coral reefs is estimated to be nearly tens of billions offsite link of U.S. dollars per year. These ecosystems are culturally important to indigenous people around the world.  

Threats to coral reef ecosystems

Unfortunately, coral reef ecosystems are severely threatened. Some threats  are natural, such as diseases, predators, and storms. Other threats are caused by people , including pollution, sedimentation, unsustainable fishing practices, and climate change, which is raising ocean temperatures and causing ocean acidification. Many of these threats can stress corals, leading to coral bleaching and possible death, while others cause physical damage to these delicate ecosystems. During the 2014-2017 coral bleaching event , unusually warm waters (partially associated with a strong El Niño ) affected 70% of coral reef ecosystems worldwide. Some areas were hit particularly hard, like the Great Barrier Reef in Australia, where hundreds of miles of coral were bleached.

Corals are able to recover from bleaching events if conditions improve before they die, though it can take many years for the ecosystems to fully heal. Scientists are also testing new ways to help coral reef ecosystems, such as growing coral in a nursery and then transplanting it to damaged areas.

A tropical paradise in the Pacific — National Marine Sanctuary of American Samoa — offers a unique opportunity for researchers to observe ocean and coral reef ecosystems that are largely considered to be remote, yet still experience pressure from humans.

EDUCATION CONNECTION

Educators can use the resources in this collection to teach students about the science and beauty of corals. They can use these organisms and ecosystems to teach many scientific concepts including symbiotic relationships, reproduction strategies, food webs, chemistry, biotic and abiotic interactions, human impacts, and more. Additionally, educators can use corals to teach about conservation and stewardship of the environment. Even if you don't live near a reef, students can learn that they can help protect coral reefs in the United States and around the world. There are many actions, small and large, that everyone can take to help conserve coral reefs .

• ENVIRONMENT

The race to create climate-resilient coral—before it's too late

In Australia, researchers are pioneering new methods to fortify coral reefs in a warming world.

In the heart of western Australia lies Coral Bay—a gem nestled within the expansive embrace of the Ningaloo Reef.

Historically, Ningaloo Reef has flourished, a kaleidoscope of coral and fish. Yet climate change’s caprice showed its hand in 2022, when weather conditions created a low oxygen event that choked the life from a section of this ecosystem.

About 70 percent of the bay’s floor had been covered by coral. By 2022, that number dropped to just over one percent.

During the same period, turf algae—small, fast-growing plants that can smother coral to death—substantially increased from covering 25 percent of the bay floor in 2021 to 79 percent in 2022.  

Despite meticulous conservation efforts, coral reefs are at risk of vanishing as the planet continues warming. Their disappearance would be disastrous—these vibrant underwater gardens are sanctuaries of biodiversity, cradling a quarter of all marine species.

An unprecedented coral bleaching event is currently affecting the Great Barrier Reef. For the first time, the entire reef is affected, according to the Australian Institute of Marine Science (AIMS). Aerial surveys show that about 730 of the more than 1,000 reefs are experiencing bleaching, making it potentially the most extensive event on record.    

FOURTH OF JULY SPECIAL

Get National Geographic magazine for $10 off

For scientists like David Juszkiewicz, a coral conservationist and PhD student at Curtin University, the race is on to create innovative solutions that help corals adapt to a new world.   While scientists say climate change must ultimately be curbed, they hope they can make corals stronger until the planet cools.

How corals react to stress

Corals, the architects of these underwater realms, are sustained by their symbiotic partners—zooxanthellae, microscopic algae nestled within their tissues. This partnership is a testament to nature’s ingenuity, transforming nutrient-poor waters into thriving ecosystems.

The zooxanthellae, through photosynthesis, provide the corals with essential nutrients, while the corals offer algae a protected environment and access to sunlight. This mutualistic relationship is the heartbeat of the reef, driving its productivity and supporting a myriad of marine life.

Yet, like any relationship, this bond is susceptible to strain. Climate change, with its rising temperatures and ocean acidification , is an ever-present threat. The symbiotic harmony falters under stress, leading to a phenomenon known as coral bleaching. In this state, corals expel their zooxanthellae, turning ghostly white and losing their primary source of sustenance. The reef’s vibrant colors fade, replaced by a stark, lifeless landscape.

Beyond the well-known coral-zooxanthellae partnership lies a complex web of microbial allies.  

Bacteria, fungi, archaea, and viruses all play roles in coral health, residing in the coral’s surface mucus, tissues, and skeleton. These microbes provide benefits ranging from nutrient exchange to pathogen defense, enhancing the coral’s resilience. High microbial diversity within the coral’s microbiome offers a buffer against environmental stress like high heat, a safeguard woven into the fabric of the reef’s existence.

That's why scientists are exploring ways to manipulate the microbes that live within coral to enhance their survival, particularly during summer heatwaves.

Manipulating a coral's microbes

Experimental evolution, where microbial cultures are selected under elevated temperatures, has shown potential as a solution. These heat-tolerant strains, once reintroduced into corals, could arm reefs with a fighting chance against thermal stress. The researcher's primary mission? That in the future, everyone can borrow and deploy this type of management action.  

“We can grow those essential coral somewhere else, under high temperatures. Then through natural selection, we can find the few cells that have the genetic material that allows them to cope with high temperatures,” Matthew Nitschke, a marine biologist at the Australian Institute of Marine Science, says.    

But it’s not just about innovation, it’s about how realistically these innovations can be shared across the globe, says Cedric Robillot, executive director of the reef restoration and adaptation program at the Great Barrier Reef Foundation.

“The Great Barrier Reef in itself is the size of Italy,” says Robillot, “How can we do that at a large scale, that will actually have an impact?”

You May Also Like

These creatures are otherworldly. They destroy coral. And they're hard to kill.

Coral reefs in the Philippines are some of the world’s most vibrant—but in peril

Climate-resilient coral species offer hope for the world’s reefs

Researchers are also experimenting with probiotic treatments, using beneficial bacteria to shield corals from diseases like the devastating stony coral tissue loss disease. Lab trials have shown promise, and efforts are underway to test these treatments in the wild.

Additionally, microbiome transplantation, where heat-resistant symbionts are introduced to vulnerable corals, could make reefs more resilient.

“Reef systems possess an innate resilience due to their interconnectedness and complexity,” says Robillot. “By reinforcing these natural strengths, we can significantly enhance their capacity to withstand and recover from stress.”

Harnessing nature’s inherent resilience

Monitoring coral health is akin to taking the pulse of the ocean. Coral bleaching is an obvious sign of distress, but subtler chemical signatures can provide early warnings of poor coral health. Scientists are developing technologies to detect these signals early so that they can intervene before visible bleaching occurs.

Juszkietiz notes that even a slight increase in temperature by 1-2°C can stress corals . These increasingly frequent events contribute to dramatic changes in coral reefs, raising the risk of silent extinctions and the disappearance of species before they can be documented and studied.

As a last ditch effort to record species before they’re lost, he locates and photographs massive Porites corals, which form large, boulder-like colonies. After logging essential information about their size, color, shape, and habitat, he then collects small samples from the colonies, which he analyzes in the lab. One sample is bleached to study the coral's skeleton, another is preserved in ethanol for DNA analysis, and a third is fixed in a formaldehyde solution to determine the coral's sex and spawning readiness—helping to identify new species and understand the range of existing ones.

“There is so much to discover,” Juszkiewicz says. “And our reefs are changing dramatically. Based on the current trajectory, we will only have reefs around for a little while longer.”

That’s what makes the fight to save coral reefs a race against time. “We have a really narrow window of time [before the damage is irreversible] —10 years or so.”

Climate models reveal a stark reality: “The first is that even if we stop emissions tomorrow, there will still be a certain amount of warming locked into ocean ecosystems. So, there’s going to be a period of time where reefs are still suffering stress.”

Researchers emphasize that while scientific research can lead to innovative solutions, it is ultimately a band-aid for a global problem. True coral protection requires a drastic reduction in greenhouse gas emissions.  

“I have a glimmer of hope—you have to,” says Juszkiewicz. “ If we want to save our reefs, we need to put the brakes on this rapidly changing climate.”  

Related Topics

• WILDLIFE CONSERVATION
• HABITAT PRESERVATION
• CLIMATE CHANGE

Why scientists are 'weeding' coral reefs

How coral reefs might survive climate change

Travelers are starting to help with coral replanting around the globe

A deadly disease is wiping out coral in Florida and the Caribbean

These photos show what happens to coral reefs in a warming world

• Environment

History & Culture

• History & Culture
• Mind, Body, Wonder
• Interactive Graphic
• Paid Content
• Terms of Use
• Privacy Policy
• Your US State Privacy Rights
• Children's Online Privacy Policy
• Interest-Based Ads
• About Nielsen Measurement
• Do Not Sell or Share My Personal Information
• Nat Geo Home
• Attend a Live Event
• Book a Trip
• Inspire Your Kids
• Shop Nat Geo
• Visit the D.C. Museum
• Learn About Our Impact
• Support Our Mission
• Advertise With Us
• Customer Service
• Renew Subscription
• Manage Your Subscription
• Work at Nat Geo
• Sign Up for Our Newsletters
• Contribute to Protect the Planet

Copyright © 1996-2015 National Geographic Society Copyright © 2015-2024 National Geographic Partners, LLC. All rights reserved

Accept cookies?

We use cook ies  to give you the best online experience and to show personalised content and marketing. We use them to improve our website and content as well as to tailor our digital advertising on third-party platforms. You can change your preferences at any time.  

Popular search terms:

• British wildlife
• Wildlife Photographer of the Year
• Explore the Museum

Anthropocene

British Wildlife

Collections

Human evolution

What on Earth?

Coral reef coverage has declined significantly since the 1950s ©Mayumi.K/Shutterstock.com

During Beta testing articles may only be saved for seven days.

Create a list of articles to read later. You will be able to access your list from any article in Discover.

You don't have any saved articles.

Over half of coral reef cover across the world has been lost since 1950

Coral reefs have declined by over half since the 1950s as they suffer from the effects of climate change and overfishing.

Across the world, the area that coral reefs occupy has fallen by 50% in the half century from 1957. Their ability to carry out key roles, such as food provision and locking away carbon, has fallen too.

Corals may be able to recover, but it will require a concerted effort to protect reefs from fishing and limit the impact of climate change. The research, led by the University of British Columbia, is published in the journal One Earth . 

Dr Tyler Eddy , the lead researcher of the study, says, 'It's a call to action - we've been hearing this time and time again from fisheries and biodiversity research.

'We know coral reefs are biodiversity hotspots. And preserving biodiversity not only protects nature, but supports the humans that use these species for cultural, subsistence and livelihood means.' 

Corals bleach as a stress response, and can lead to death if too frequent. Image by Vardhan Patankar, licensed via  Wikimedia Commons CC BY-SA 4.0 .

Coral calamity 

Coral reefs are one of the most important underwater habitats . While tropical corals are the most well-known, coral reefs exist in a variety of places. Even the UK has cold water reefs off the coasts of Cornwall and Scotland. 

This new study focused specifically on tropical corals, which are important for both aquatic species and humanity as a source of food in the ecosystem. Corals do so by forming skeletons of calcium carbonate, which provide reefs where species can shelter and breed. 

But these skeletons make corals vulnerable to rising carbon dioxide levels in the atmosphere as the gas dissolves into seawater and makes it more acidic . This dissolves corals' calcium carbonate structures, which in turn reduces the amount of carbonate available for corals to build the skeletons back again. 

Warming temperatures are also a risk, as spikes in temperatures cause corals to eject the photosynthetic algae that live inside them. While these events, known as bleaching , are a normal stress response for corals, they are becoming more frequent. Repeated bleaching can cause corals to die. 

Studying the period between 1957 and 2007, the researchers found that the coverage of living coral on reefs had fallen by around 50%. Most countries showed a decline of up to 6.8% per decade though a few, including Japan and Malaysia, showed increases during the period. 

As coverage declined, this had impacts on the species that are supported by coral. The biodiversity of reefs was found to have declined by 63%, while the abundance of fish species fell by 60%. 

In many cases, the exact extent of the losses are unknown as historic records on the condition of reefs in the 1950s and 60s in many areas of the world are often lacking. While this has improved with time, some areas of the world still have limited records available to analyse. 

Many people around the world depend on coral reef fishing for their survival and livelihood ©Ethan Daniels/Shutterstock.com.

Fishing falls 

While the impact on the corals themselves is severe, the impact on the people who depend on them is also is also taking a significant toll. 

Fish form a large part of the diet for many people, while it is estimated that around six million people depend on fishing coral reefs for their livelihood. 

This new analysis found that many people's diets and livelihoods are already being affected by the changes in coral reefs. Since 2002, catches have been declining year-on-year even though fishing effort has been increasing.  

Co-author Dr Andrés Cisneros-Montemayor says, 'It's heart-wrenching for us to see photos and video of wildfires or floods, and that level of destruction is happening right now, all over the world, to coral reefs. 

'It is threatening people's culture, their daily food, and their history. This isn't just an environmental issue, it's also about human rights.' 

Steps are being taken to protect coral reefs, with efforts to restore them through transplanted corals grown elsewhere, or to artificially cool them with pumps.

Work is also being undertaken to protect fisheries, with protected areas and quotas being introduced in an attempt to allow the reefs to recover. 

However, the efficacy of these steps varies, and so the researchers have called for a global effort to combat the mix of issues that affect coral reefs.

They hope to see an integrated approach between the nations of the world on climate, biodiversity and fishery policy to help turn around the declines that reefs are currently experiencing. 

• Coral reefs
• Climate change
• Biodiversity
• Read the research paper in the journal  One Earth .

Protecting our planet

We're working towards a future where both people and the planet thrive.

Hear from scientists studying human impact and change in the natural world.

Discover more about coral reefs

The resilient coral reefs surviving ocean warming

Ocean warming is threatening coral reefs but some reefs are surviving the warming waters and offer hope for these vital ecosystems.

Ocean ecosystems are more sensitive to climate change

Climate change is having a bigger impact on animals and plants in the ocean than those on land.

Why the Coral Triangle is the most important part of the ocean

It's the most diverse part of the ocean, but plenty of people have never heard of it.

Staghorn survivors: the world's most successful coral?

Layers of rock off the coast of southern England reveal surprising clues about the past and future of today’s coral reefs.

Don't miss a thing

Receive email updates about our news, science, exhibitions, events, products, services and fundraising activities. We may occasionally include third-party content from our corporate partners and other museums. We will not share your personal details with these third parties. You must be over the age of 13. Privacy notice .

Follow us on social media

Palau luxury cruise: coral reefs, white sand beaches, Jellyfish Lake and WWII relics from US$3,000-a-night catamaran

• Palau, a nation of islands in the western Pacific, offers white sand beaches, clear blue water and some of the healthiest coral reefs on the planet
• Touring it aboard the Four Seasons Explorer, a catamaran that sleeps up to 22 people, is one way to take in a place where conservation is king

The first emerges through the misty water like an apparition, as round and delicate as a smoke ring.

A moment later, a second comes into view, the size of dinner plate, its ghostly white frame pulsing in and out. Then another, as small as a button mushroom, floats right past my face - and another, perhaps 50cm (20 inches) in diameter, contracts eerily below.

Dozens of moon jellyfish and larger golden jellyfish, with frilly crowns and ruffled tentacles that make them look like Victorian lampshades, are blooming all around me.

Do you have questions about the biggest topics and trends from around the world? Get the answers with SCMP Knowledge , our new platform of curated content with explainers, FAQs, analyses and infographics brought to you by our award-winning team.

This might seem like the opening scene of a horror movie but Ongeim L'Tketau - also known as Jellyfish Lake - home to approximately one million stingless Scyphozoa, is one of Palau's most popular tourist attractions.

I'm embarrassed to admit that before my visit I wasn't entirely sure where Palau was, but after pinpointing it on the map and widening, widening - and widening - the screen, I discovered that the Republic of Palau is in the far western Pacific, east of the Philippines, north of Indonesia and west of Hawaii.

It's part of the islands that make up Micronesia, but not one of the Federated States of Micronesia, which comprises Yap, Chuuk, Pohnpei and Kosrae.

It has a population of just 20,000, spread across 458 sq km (177 square miles) of bright blue ocean and somewhere between 340 to 500 coral and volcanic islands (depending on whether you count the very little ones), making it one of the world's smallest nations in terms of land area.

It's also arguably one of the world's most beautiful; a fantasia of pom-pom-shaped islands fluffed with 178 endemic plants and dozens of rare bird species, caged in vast coral reefs set in the luminous blue Pacific.

A boat is really the only way to explore Palau. Until recently, that meant having access to a superyacht or hopping on a back-to-basics liveaboard, eating buffet dinners and sleeping in bunk beds.

Unspoilt bay in Sri Lanka aims to stay that way with tourism set to boom

Now there's another option: the Four Seasons Explorer, a 128ft double-hull catamaran with 10 state rooms, one Explorer Suite, a fleet of aqua toys and a staff of 25 (for a maximum of 22 guests).

The yacht glides around the country, predominantly the Unesco World Heritage Rock Islands region, and guests can arrive and depart by speedboat any day of the week and stay for as many or as few days as they like, rather than having to conform to the usual seven-night itineraries that most cruises offer.

It costs US$3,000 per cabin per night, and includes gourmet meals (drinks cost extra), as well as cultural excursions to caught-in-time villages, tours with a local historian of the World War II relics that pepper Peleliu island, trips to Jellyfish Lake, stand-up paddle boarding through limestone arches, and diving.

"These are the best corals I've ever seen," says Michael Cohen, a lawyer and philosophy lover from San Francisco, who's celebrating his wife's 60th birthday.

"We used to go diving in the Caribbean, but it's not in as good shape as it used to be. You have to travel further and further out now to find really healthy marine life - in the past few years we've been to Indonesia, the Seychelles, the Maldives and now Palau."

Palau is blessed with underwater gardens of giant coral roses with blush-pink petals unfolding down to the seabed; vast forests of lavender staghorns with electric blue tips; fields of quivering purple things that look like egg waffles; brain corals as big as two-bedroom bungalows. It's also, as far as I can tell, free from plastic litter.

The pristine surroundings aren't down to chance. Since gaining independence from the United States in 1994, the people of Palau have made a concerted effort to protect the country's culture and environment, even encoding the "conservation of a beautiful, healthful and resourceful natural environment" into the constitution.

The country is one of the world's largest marine reserves, with 80 per cent of its waters protected from all types of fishing and mining, as well as incorporating the world's first shark sanctuary. It is against the law to take or kill any birds, eggs, marine life, shells or plants.

When I arrived in the country, greeted by possibly the world's friendliest immigration officer, I was asked to sign the Palau Pledge - which takes up an entire page of my passport - promising to respect the environment for the children of Palau and future generations.

In a world buckling under overtourism, this feels like a genuine revelation.

"Our former president wanted Palau to focus on high-value visitors like the Four Seasons guests as they are more interested in our culture and more respectful of our culture," says Olympia Mori.

Mori is the director of the Belau National Museum in Koror, and an ourrot , a female village elder.

In this matrilineal society, women are the decision-makers, with the ability to appoint - and remove - the village chiefs. They often go on to hold seats in Palau's parliament.

Women also handle all of the money: traditionally, clay and glass beads, as well as more valuable hawksbill turtle shell trays. Now, it's the US dollar.

"I think tourism is good for us. At the moment, our young people fare better outside Palau than here," says Mori, referring to the outflow of young people to the US (of which Palau remains a trust territory) for military service or in search of jobs.

"We need the tourism industry to offer them the right opportunities, the right training that respects our culture, and the right compensation."

There are no Palauan staff working on the Explorer during the week that I'm a guest. But more than a dozen young recruits are undergoing training at the Four Seasons Kuda Huraa and Four Seasons Landaa Giraavaru , both in the Maldives.

A member of the dive team, Hongkonger Leung Tsz-wai, also known as Leo, leads me through the spooky smacks of jellyfish, teaches me to dive while snorkelling and cheerfully points out the marine life - clown fish, napoleon wrasse, a delightful nudibranch and a couple of octopus engaged in an inky battle.

What we don't see is any coral bleaching or signs of serious environmental damage.

That's not to say Palau isn't at the mercy of climate breakdown from rising sea levels, ocean acidification and more extreme weather events. But following traditional basic principles, known as the kelulau , which include respecting and honouring the environment, compassion and cooperation, unity and good conduct, at least Palauans can say that they're doing almost everything they can to mitigate that risk.

As fascinating as it is beautiful, the rest of the world could learn a lot from this little island nation.

Lee Cobaj was a non-paying guest of the Four Seasons Explorer.

More Articles from SCMP

Hong Kong’s ‘Art March’: Henderson Land construction site adds splash of colour to Central harbourfront with illustration-covered hoarding

Taylor Swift fans in Singapore who failed to get tickets to The Eras Tour flock to Filipino impersonator’s drag act

Ben Thompson loving life in Hong Kong: ‘I couldn’t be happier to be staying here longer’

Singapore ex-minister S. Iswaran slapped with fresh corruption charges

This article originally appeared on the South China Morning Post (www.scmp.com), the leading news media reporting on China and Asia.

Copyright (c) 2024. South China Morning Post Publishers Ltd. All rights reserved.

Happy Coral Reef Awareness Week! What you need to know about Florida’s Coral Reef

Coral reefs are both beautiful and utterly vital to the ocean ecosystem and the local environment. They provide homes, food and breeding sites for millions of marine plants and animals, including the fish we eat. They offer important resources we've used to fight cancer, pain and inflammation. They help protect shorelines from extreme weather, erosion and flooding, and they provide income through fishing and tourism for millions of people.

Corals, animals that range in size from a pinhead to a softball , are invertebrates that become permanently fixed in place as they grow vibrant and colorful external skeletons. Individual corals, called polyps, grow slowly and form different shapes ranging from rocks, mushrooms, trees, graceful waving fans, even a human brain and more, depending on which of the hundreds of coral species they are. Sometimes they can be mistaken for plants. Some are even fluorescent.

When they connect with each other and other animals with the same structure they create, essentially, scaffolding for large communities in complex, wide-ranging reefs that support more species than any other marine habitat. Think of corals as trees in an underwater rainforest, supporting a rich, biologically diverse population of life underwater. Colonies of coral in the reef can live for hundreds of years.

In honor of National Coral Reef Awareness Week (the third week of every July), here's what you need to know about ours.

What is Florida's Coral Reef?

Florida's Coral Reef is the only coral reef system in the continental United States and the third-largest barrier reef ecosystem in the world.

Stretching nearly 350 miles from Dry Tortugas National Park west of the Florida Keys to St. Lucie Outlet north of West Palm Beach, it's made up of over 40 species of corals including one colony over 300 years old, according to the Florida Department of Environmental Protection (FDEP). About two-thirds of the Florida Reef Tract is inside Biscayne National Park and the Florida Keys National Marine Sanctuary.

It's also important to Florida. A large part of our fishing industry survives on fish that breed and grow in the coral reef.

"It also supports over 71,000 jobs and generates over $6.3 billion in tourism revenue every year,” said Darren Soto, D-Kissimmee , at an event for SeaWorld Orlando's new Coral Rescue Center in June. Millions of people come to fish, dive and snorkel around these reefs and see the brilliant fish and marine life dependent on them.

And the reef helps protect the coast, the first line of defense for a state that gets slammed with hurricanes and tropical storms every year. "Florida’s Coral Reef provides more than $355 million per year in flood protection benefits to buildings," the FDEP said on the floridascoralreef.org website, "and protects nearly $320 million in annual economic activity."

About 25% of the ocean's fish depend on healthy coral reefs

Coral reefs cover only a tiny area of the ocean floor — about 1% of the total marine habitat — but, like bustling cities, they provide homes and life to a wide variety of life.

"Coral reefs are among the most biologically diverse and valuable ecosystems on Earth," according to the U.S. Environmental Protection Agency. "An estimated 25 percent of all marine life, including over 4,000 species of fish, are dependent on coral reefs at some point in their life cycle. An estimated 1 billion people worldwide benefit from the many ecosystem services coral reefs provide including food, coastal protection, and income from tourism and fisheries."

Coral reefs are easily damaged

For something with such a powerful effect on the ocean environment, coral reefs are extremely fragile. Corals rely on algae living inside their tissues to provide nutrients. When the coral is stressed by changing water temperatures, pollution or too much sunlight, they expel that algae, causing the corals to "bleach" or turn white. Bleaching itself does not kill corals, but it leaves them susceptible to disease or starvation.

The primary cause of large regional or mass bleaching events is rising sea temperatures . These events, first noticed over 40 years ago, have become more frequent and more intense. The worst so far was the Great Coral Bleaching Event from 2014 through 2017, when already warm sea temperatures were increased El Niño, causing heat stress to spread across the world and into regions that had never bleached before, such as the north part of the Great Barrier Reef in Australia. Half of the coral reefs in the world were affected.

Coral reefs are also damaged by poor water quality, ocean acidification, sea level rise, tropical storms, pollution, storms, overfishing, bottom-trawling (dragging a weighted net across the seafloor), misplaced boat anchors, stress from high population densities and coastal development, sediment and nutrient runoff, direct contact by careless tourists and more.

Florida's reefs have been declining for the last 40 years, according to the EPA , with many of them losing more than half of their coral cover. Twelve coral species off our coasts have been designated as endangered . But the biggest threat facing Florida's reef for the last ten years is a disease.

Florida's coral reef is being attacked by a disease

"The Florida Reef Tract is currently under siege by a very lethal disease called Stony Coral Tissue Loss Disease," Jim Kinsler, zoological curator at SeaWorld Orlando and manager of the Florida Coral Rescue Center, told FLORIDA TODAY. "The disease, once a coral colony contracts it, is almost 100% fatal to that colony."

Biologists say Stony Coral Tissue Loss Disease, originally dubbed "white syndrome," is unprecedented and has been killing more than 20 Caribbean coral species and coral on Florida’s reefs since 2014. A  study  last year by NOAA and the University of Miami found 70% of the Florida Coral Reef is eroding faster than it's growing.

The disease began near Miami and has since spread through the northern extent of Florida's reef tract in Martin County, south through the Florida Keys, and west into the Marquesas, according to the Florida Fish and Wildlife Conservation Commission.

The precise cause is unknown.

There's a plan to save Florida's coral reef

In December 2019, the National Oceanic and Atmospheric Administration enlisted The Florida Aquarium, the Coral Restoration Foundation, Florida Department of Environmental Protection, Florida Fish and Wildlife Commission’s Fish and Wildlife Research Institute, Mote Marine Laboratory & Aquarium, Reef Renewal and The Nature Conservancy to join in a $100 million effort called Mission Iconic Reefs to restore coral at seven sites along the Florida Reef Tract, off the state's southern tip.

That plan has an ultimate goal of restoring 3 million square feet of coral reefs — roughly the size of 52 football fields — by 2035 by planting hundreds of thousands of coral fragments to promote reef growth and thousands of Carribean king crabs to eat algae and make the environment more hospitable. SeaWorld Orlando's Coral Rescue Center is working to store the most resilient coral genetics in the hopes of creating disease-resistant coral to transplant back into the wild.

You can help save Florida's Coral Reef

The Nature Conservancy has some suggestions to help protect Florida's Coral Reef.

• Avoid touching coral. When you dive, don't touch the reef. Corals are living animals and contact can damage them. Avoid stirring up sediment, which can smother corals. When boating or fishing, be mindful of where you go and especially where you drop anchor.
• Use mineral-based sunscreens. Chemicals like oxybenzone and octinoxate, used in many sunscreens, can damage corals and decrease their defenses against bleaching. Look for sunscreens that use non-nano zinc oxide as their active ingredient.
• Eat sustainable seafood. Research where your seafood comes from and if it's caught sustainably. Skip the parrotfish: they eat algae off coral reefs, cleaning the reefs and helping the corals stay healthy and thriving.
• Pick up your trash. Millions of tons of trash end up in the ocean and it can damage marine life, including corals. On the beach or on the water, pick up your trash or any that other people have left behind.
• Make your lawncare green. Even if you live hundreds of miles away from the coral reef, the stuff you put on your lawn will eventually flow into the water system. Use green alternatives for fertilizer and pesticides that won't harm marine life.
• Volunteer. If you're in the area, the Coral Restoration Foundation is always looking for volunteers in and out of the water. Divers (with proper certification) can help with nursery work, transplanting corals and monitoring their health. Land-based volunteers help build coral trees, help in the Education Center and conduct community outreach. Divers also can help the Mote Marine Laboratory with its Bleachwatch to monitor and report on conditions. The Reef Environmental Education Foundation holds the Great Annual Fish Count every July to encourage recreational divers and snorkelers to conduct fish surveys while they're down there, but you also can do that all year round . If you're not ready to jump in the water just yet, all of those organizations gladly accept donations.