Skip to content

Repairing the Decline of Coral Reefs – Why we are failing; What is needed to succeed


This post first appeared as a Comment in Reef Encounter – the News journal of the International Society for Reef Studies. It is reprinted here, with added images and slight modifications to text as a way of drawing it to attention of other people interested in the global environmental crisis and the issues underlying our relative failure to look after coral reefs. Reef Encounter is open-access, and the articles are of broad interest.


There is something mesmerizing about the lushness of life and the richness of form on a coral reef; few other environments come close to packing so much liveliness into each cubic meter of space. Photo © AJ Hooten.

Humanity faces a challenge which if not existential certainly threatens our civilization, and, as Pogo found out long ago, the enemy is us. Our varied impacts on the biosphere grow larger as our population and our standards of living grow, and now we are numerous enough and powerful enough to be causing serious damage. Coral reef scientists are generally well aware of the seriousness of our situation – our special parts of the biosphere are among the most, if not the most, impacted on the planet and suggestions that coral reefs as we knew them in the mid-20th century could be largely gone by mid-21st century are not far-fetched conjecture but reasoned assessments by scientists who look at the evidence of reef decline. So, what can be done for reefs, and for the wider biosphere and ourselves, and what role should reef scientists and managers play? Here are four steps we need to take to stem the decline of coral reefs.

I suggest we first need to recognize the problem. It is global. It is multifaceted. The facets differ in degree of importance from place to place. And our assessment of the problem involves value judgments – we are inadvertently forcing on the biosphere changes that we do not like, or that we suspect will be harmful to our personal quality of life or our economy. These statements are true even if we restrict attention to coral reef systems: Reefs appear to be in decline almost everywhere, with less abundant and less healthy coral, fewer fish and other reef organisms, less biodiversity, and we suspect, less ecological resilience. But the reasons for this decline vary. Loss of coral cover on the Great Barrier Reef in recent decades has been due primarily to physical damage from tropical storms, outbreaks of Crown-of-Thorns starfish, and bleaching due to climate change (De’ath et al 2012).

Death et al 2012 PNAS F2.large

Graphs A to D show change in coral cover at 214 monitored reefs over 27 years on the Great Barrier Reef. Only the northern set of sites (B) fails to show a downward trend through time. Graphs E to H show the extent of annual mortality due to each of the three primary causes for each year; these three causes are outbreaks of predatory crown-of-thorns starfish (COTS), cyclonic storms, and coral bleaching. Figure © G. De’ath et al., Proc. Natl. Acad. Sci.

Loss of coral cover in the Caribbean over the same time period has been due principally to outbreaks of diseases, overfishing, and excessive rates of coastal tourism (Jackson et al 2014). The most critical diseases have hit Caribbean corals, especially the two species of Acropora, and the sea urchin, Diadema antillarum; both acroporids are now on the US EPA endangered species list, and Diadema nearly went extinct throughout the Caribbean although its numbers are now rebuilding slowly in many locations. These pathogens may have been introduced from outside the region by humans, may have been facilitated by pollution, overfishing, or the warming and bleaching caused by climate change, and might even be spread by snorkeling tourists. Within both the Caribbean and the Great Barrier Reef there are places where reef condition has degraded substantially in recent decades and places where it has degraded less. Rates of decline vary through time, and differently among locations. Data for other parts of the world are less comprehensive but the variation in degree and putative cause is also evident in these other places.

Status & Trends Fig 4 A-C

Patterns in loss of coral cover at three types of sites across the Caribbean: A) 9 locations with sharp early decline, B) 5 locations showing a gradual downward trend, and C) 7 chiefly southern locations showing little or no loss.  Figure © J Jackson et al. and IUCN.

Every one of the causes I’ve mentioned, including Crown-of-Thorns outbreaks (Brodie et al 2005), is directly due to or exacerbated by human activities. And, as a general rule, more remote locations, such as Kingman Reef (in the Line Islands, and part of the recently expanded Pacific Remote Islands National Marine Monument), seem generally to be in better overall condition than those close to people, because most of the causes of decline are due to local human activity. Of course, we can anticipate that climate change and ocean acidification are going to become ever more important as causes of reef decline, meaning that in time the overall mix of causes of reef decline will be less easily remedied by local actions than they are at present.
It should be obvious that there is no one action that can be taken to ‘repair’ all coral reefs, but it may be less obvious that solving one problem at a time at a location may not lead to any improvement in reef condition until most or all problems are addressed. Solving problems of overfishing does not make much difference if a reef is also experiencing pollution; reseeding diseased coral with healthy cultivated juvenile colonies does not help if the disease organisms remain in the area. Reef decline is multifaceted and the facets likely interact in complex ways.

If the first step is to recognize the nature of the problem, the second step is to recognize that we do have feasible solutions for many of its facets. This is the good news which may not be getting through to the public. We have known for a long time what is needed to correct overfishing, how to avoid delivery of pollutants from on-shore activities and population centers, and how to manage coastal development in ways that do not impact adjacent reefs negatively. We understand what we have to do to control climate change and limit ocean acidification although these solutions are much more difficult to put in place. We understand which facets are capable of being corrected by the creation of marine protected areas, and which facets an MPA cannot affect. Mostly, the fixes needed are not even particularly challenging technically, although that does not mean they are simple to enact.

Recognizing that we do have solutions leads immediately to the third step — to acknowledge that, although we have solutions, we have not been applying them effectively. In fact, over many years, we in the science and management community have been woefully ineffective in solving the problems that are leading to reef decline, and it is well past time to replace the wasted efforts under way with more effective action.

Why have attempts to address reef decline been so ineffective, and why do we avoid talking about this? I suggest that the reasons for failure, while diverse, stem from a core feature of environmental management – it is not really management of environment but management of people; living, breathing people with families, societies, cultures, religious beliefs, traditions, stubbornness, dishonesty, corruption, short-term thinking, mortgages, and many things on their minds beyond improving coral reefs. Some live near reefs, feed their families from fish caught there, earn a living in reef tourism, or work in NGOs or government agencies; others work at jobs quite unrelated to reef condition and may only visit reefs occasionally. Still others are government officials, international experts, well-meaning philanthropists or dedicated conservationists directly concerned with improving reef management. Making real changes in the lives of any of these people can be very difficult. Many of them ‘know’ that the ocean is limitless, that there will always be baby fish, even if we catch all the adults, or that God or Nature will always take care of us. Others do not want to see changes that reduce their incomes, influence, or importance. Some, working hard to bring change, fall into the social worker trap – if the problem is finally fixed their jobs risk coming to an end. Over time we have spent far too much time thinking about how to manage reefs, and not enough time thinking, and learning, about how to manage people.


In reality, effective management of coral reefs and other coastal waters is management of behavior of the coastal populations that use those waters. It is very challenging to convince people who fish to feed their families that they must fish less, or fish in different locations than they always have, and often requires that their local economy be remade. The same difficulties exist when coastal populations must be convinced to modify the way in which they dispose of wastes, or inland farming communities must be convinced to modify their use of fertilizers, pesticides and irrigation.
Photo © Yvonne Sadovy de Mitcheson

Reasons for failing to talk about the prevalence of failure are more simple. Nobody wants to admit to failure, or to allow the possibility that they do not know how to fix the problem of overfishing, or pollution, or whatever. And we have convinced ourselves that telling the truth about the environmental crisis simply depresses people. Better to talk about the occasional good news stories when things happened to go right. Better still to pretend that the failures are in fact successes – how else to account for the evident pride with which governments, NGOs and other bodies proudly proclaim the number of km2 protected in marine protected areas, or display the printed MPA management plans, legislation and regulations when everybody knows that in the great majority of MPAs no real protection is taking place?

Don’t get me wrong. There are well-managed MPAs, both in wealthy and in developing countries, and there are other instances of reef management which is effective. Some of us are doing it right. Still, when one can snorkel through an MPA, and then through a nearby ‘unprotected’ site and see no evident difference in fish size or abundance (as is a very common experience across the Caribbean, and in other places as well), one knows that ‘no-take’ provisions are not being enforced. When one sees mangrove forests along Mexico’s Mayan Riviera being cleared and readied for hotel development right after a hurricane, ostensibly because, stripped of leaves, they are now ‘dead’, or hears of massive plans to dredge new harbors, risking nearby ‘protected’ reefs, because the Australian coal industry absolutely must export its products more quickly, or finds a lobster dinner not on the menu but still readily available out of season, so long as the request is made quietly at a table in a far corner of the Belize City restaurant, one knows that efforts to preserve or repair reefs are not working. I’ve experienced all of these. Yet still we carry on, developing projects, raising funds, reporting numerous workshops and conferences designed to improve reef management, while consistently failing to create the real, and enduring, changes in human behavior that are essential for improvement to happen.


Mangroves, which are important nurseries for many reef species, are widely regarded as waste land. They get cleared for shrimp farms and luxury hotels, sometimes legally, sometimes bending every rule in the book. This excavator is operating just outside the boundary of a not very well managed MPA in Bimini, Bahamas. Photo © K. Stump, Story in

As a recent example of this tendency to gloss reality with a glitter of false good news, consider the latest report on the state of the Caribbean (Jackson et al 2014). A careful read of this IUCN report provides abundant data, careful analyses, and sad conclusions on what has been happening to Caribbean reefs. The science is well done. The authors do a generally responsible job of assessing competing hypotheses. They state, quite clearly that “the disparate reef histories clearly demonstrate the folly of attempting to understand the causes of coral reef decline for the entire Caribbean as a single ecosystem, an approach that ignores the enormous heterogeneity in environments and history of human and natural disturbance among different reef locations.” With a careful read, this is a solid report that assesses the data, points to the seriousness of current trends, and makes clear recommendations for action.

stoplight parrot steneck

Protecting parrotfishes will be a worthwhile management action in many Caribbean locations because they are effective grazers that prevent algae from becoming sufficiently abundant to shade out coral and take over available rocky surfaces. But protecting parrotfishes does nothing to correct other types of damage on coral reefs. Photo © Robert S Steneck

But with a skim of the Executive Summary (the only part also available in Spanish or French), or a look at IUCN’s press release, or at various stories in the media from local Caribbean newspapers to Time Magazine, a rather different story emerges. This one is far more about the value of protecting parrotfishes! Whether the authors intended it or not, a detailed, difficult, somewhat depressing tale, with sound recommendations (including the protection of parrotfishes), has been morphed by IUCN and the media into an upbeat story about a serious problem which can be fixed simply by taking care of parrotfishes. So much for the authors’ warning about the ‘folly’ of expecting a single, simple cause of coral decline across the Caribbean.
The fourth step; once we acknowledge our failures – we have to change our own behavior, reject failure and demand real success.  Most current and past projects designed to improve reef management can be characterized as too small, too short-term, too narrowly focused on a single facet of reef decline, with far too little attention to the socio-political components of the problem, and with far too little investment in public education and the building of a broad consensus in support of the new management actions and regulations being introduced.

REEF workshop cropFiji workshop CROP

The process of improving coastal and reef management requires that all stakeholders, including all relevant management agencies, come together and work collaboratively on common goals. This is difficult to achieve, and requires effective leadership, clear long-term objectives, and significant attention to the needs and aspirations of each stakeholder group. We have tended to give too little attention to the culturally-sensitive task of building and sustaining effective teams.
Figures © REEF.ORG (above) and the Coral Gardens Initiative of Fiji (below).

The international development community has talked for years about the need for integrated reef management, a holistic perspective, projects designed at ecologically appropriate spatial and temporal scales, and with the building of community and governmental buy-in that is essential for success. Most projects fail at all of these challenges. In a recent article in Marine Pollution Bulletin (it’s open access so easily accessible) we make one suggestion for breaking through this log-jam of failure. We argue that we need to recognize that it is now essential that we begin to zone the coastal ocean, much as we do land, in order to systematize and prioritize among competing uses as we undertake formal use planning. The ocean as wild frontier is disappearing and the coastal ocean, where nearly all reefs occur, is too crowded to be viewed that way. Marine spatial planning (MSP) is a tool for objectively dividing up an ocean region that includes varying habitats, ecological processes and traditions of use so that sufficient and appropriate space is available for each type of use or ecological process. It has been used successfully in developing networks of MPAs, but could be used more broadly to govern all our uses of a region of ocean. A greatly expanded use of MSP could provide an objective way of making the necessary zoning decisions. More importantly, if made central to a project, MSP would help jump-start the collaboration, effective cross-agency effort, setting of appropriate spatial and temporal scales, use of a holistic perspective, building of consensus and demand for real results that are so often lacking in international development projects that aim to improve coastal and reef management. The integrated, holistic, approach, at ecologically appropriate spatial scale is necessary for real success, but unlikely to appear spontaneously given the usual mix of competing agencies and competing goals of various stakeholders – MSP could be the trigger needed to tip effort in the right direction.

Success still will not come if real, committed leadership does not exist, but given leadership, success has a much greater chance of appearing than if we continue our current failed approaches. I think we scientists and managers all have a moral obligation to join forces to recognize and articulate reality, admit to our pervasive failures, improve monitoring and experimental evaluation of competing causes of reef decline, and build management to reverse the decline of coral reefs. Reefs could be in much better condition if we acted more effectively than we have been, and better reefs mean better lives for millions of people who depend on them.

global coastal population MPB 2014compressed

Twenty percent of the 7 Billion people on our planet live in the tropics and within 100 km of a coast. That tropical coastal strip represents just 7% of the global land surface, and people live there at an average density of 141 people per km2. Many of these people are directly dependent for food, income and quality of life on the coastal marine environment and its reefs, seagrass beds and mangrove forests. The map shows current population size in the coastal strip. Tropics of Cancer and Capricorn delineate the tropics. Figure © Sale et al., Marine Pollution Bulletin

4 thoughts on “Repairing the Decline of Coral Reefs – Why we are failing; What is needed to succeed”

  1. Hi Peter. I tend to agree with you regarding the primary focus should be on ‘managing people’ wrt coral reef conservation, but I am not so sure that this should be the only focus as a good understanding of the distribution and dynamics of reefs and resources should be part of the solution as well. I have long believed from my 7 years mid Pacific work experience is that local people understand the ‘where, what and when’ of reef resources but are understandably unclear on the ‘how’ and ‘why’.

    For example, I think there is less appreciation of the inter annual variability of resources and a lot of myths that correlate with a lucky juxtaposition of an activity and obvious natural recruitment pulse. As an example, many Pacific Island people do not believe that the coconut crab has a hermit shell phase and even when advised of this I have been told by locals that I am wrong! I was suggesting that both the taking of hermit crabs for bait and the overharvesting of gastropods like the green snail was reducing the number of new coconut crab recruits and the ‘homes’ for young coconut crabs. A tough sell!! But this is where the scientific knowledge input can and should be part of the overall management approach.

    Selective timely advice based on local scientific/biological knowledge can and should be part of the overall strategy given the condition of so many heavily harvested reef resources. I remember an anecdote from Ed Gomez back in the ’90’s where his Bolinao team advised local urchin roe harvesting to be delayed by 2 weeks to allow for approx. 50% of the population to naturally spawn. This resulted in significantly higher urchin densities the following year and so the declining industry was reinvigorated by the annual timely intervention of scientific advice as to the starting date for urchin harvesting to allow for a proportion of the population to spawn. I think that further input was needed some years when the prevailing water circulation patterns changed under certain weather conditions such that for some years the recruitment pulse did not happen as predicted. So to just think that no biological input is required and that dealing with the ‘people issues’ will solve it all is swinging the pendulum too far in the opposite direction in my opinion. Cheers

    1. Hi Dave,
      Fascinating story re the Coconut crabs. In Jamaica in the late 1980s I was told trap fishermen believed strongly that ‘the baby fish come in from the ocean’ and that taking all the adults would not interfere with this.
      I think you misunderstood my comments. The science is absolutely necessary, but in most cases, far too much effort is made to get the reef science right, and far too little to get the social science right. We need to remember that we are trying to change human behavior — an enormous challenge.
      Finally, the mid-Pacific may well be one of those parts of the world where the local people understand their coastal marine ecosystem. On many continental shores, there is little appreciation or understanding of what lies below low tide, and development projects spend far too little effort on the outreach and education that is needed if practices are going to be changed.

Comments are closed.