Coral Reef Crisis

The environment changes. The changes are great over human lifetimes but subtle over a few months or years. Change creeps up on us unnoticed until there are no more big fish in the sea or we run out of drinking water and we wonder why. Then we start to worry and try to decide what to do, but our standards for improvement are much lower than before because we did not notice the changes as they occurred. Fisheries biologist Daniel Pauly introduced the term “Shifting Baseline Syndrome” in reference to such declining standards and aspirations for nature. In ecological jargon, “baseline” refers to the initial, pristine state of a community of organisms. However, scientists began to study nature long after intensive exploitation and pollution had greatly reduced stocks of living resources to the point that baselines are difficult to construct.

Nowhere is the problem of shifting baselines greater than for coral reefs. During my thirty-year career, I have watched every coral reef ecosystem I have studied change almost unrecognizably from the way it used to be. But when I try to explain these changes to younger scientists who were not there before they are sceptical because who could possibly imagine that such changes have occurred? There is a generation gap in scientific perspective.

The problems are the usual list of overfishing, pollution, introduced species, and global climate change – although in most cases the relative importance of these different human activities is not as well understood as we would like. The widespread occurrence of trophic cascades due to overfishing is particularly difficult to unravel because the keystone species were so often reduced to ecological extinction decades before ecological studies began. Regardless of the exact cause, the implications are dire for coral reefs and for the people who depend upon reefs for food and other resources. The economic implications are particularly severe in developing countries that are least equipped to cope with the change.

Coral reef scientists wee inexplicably reluctant to recognize the global crisis in the state of coral reefs. This was all too evident in the slow realization that outbreaks of coral disease, coral bleaching, fleshy algae, and crown-of-thorns starfish pose a genuine danger to the future of coral reefs around the world. Indeed, the first international meeting to attempt to rigorously assess the status of coral reefs worldwide was not held until 1993. At that meeting, many scientists, especially those from prosperous nations, still denied that coral reefs were in serious decline.

There is no doubt that coral cover and the abundance of fishes and numerous free-living invertebrates have greatly declined in well-studied situations such as the reefs of the Florida Keys, Jamaica, or the Netherlands Antilles. There are also excellent time series available from several sites on the Great Barrier Reef where scientists and managers are beginning to realize that ever the best protected reefs in the world are exhibiting serious reasons for worry. But until very recently, coral reefs in the developing world received much less and more superficial attention, even though their reefs are subjected to more intense exploitation anddamage than the reefs of wealthier nations, In addition, there has been too little attention paid to remote sites where the effects of human disturbance may be less than closer to centers of human population.

For all these reasons, it is essential that we develop a clearer understanding of the global scope of the decline of coral reefs. There are many approaches to obtaining such data, all of which revolve around the trade-offs between exclusive involvements of a few professional coral reef scientists versus increasing the numbers of observers through the use of volunteers. Volunteers greatly increase the scope of the surveys that are possible and therefore greatly increase the sample size of reefs examined. This is what Reef Check has managed to do so impressively over the last five years. The results, although preliminary, support the view that the problems of coral reefs are genuinely global in scope.

Nature is complicated and coral reefs, like other ecosystems, change for all sorts of reasons besides human actions. Thus time series of only five years duration are open to different interpretations and manly more years of observations will be required to identify trends. Nevertheless, Reef Check surveys suggest several fold declines in numerous species that are cause for genuine concern. It is particularly disturbing that abundance of reef fishes like snapper groupers, parrotfishes and grunts continue to decline in the Caribbean where one might have expected they ha d already reached rock bottom.

By far the most disturbing results, however, concern the nearly universal disappearance of heavily exploited species from reefs around the world except in a few moderately well protected areas. Nassau Groupers were once among the commonest fishes throughout the Caribbean but were absent from 82% of the 162 Atlantic reefs surveyed. Likewise, bumphead parrotfish and humphead wrasse were virtually absent from the Pacific reefs surveyed except for a few protected areas. This universal rarity of once common and ecologically important species confirms the global extent of coral reef decline.

Last but not least, the volunteer program Reef Check provides a valuable opportunity for divers and snorkelers to take a fist step towards learning more about the threats to coral reefs and the importance of greater care and protection.

Reef Check is to be congratulated for their important contribution to our understanding of the magnitude and extent of the threats to coral reefs around the world.

Jeremy Jackson

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