7. Sea sickness: oceans and fisheries in peril

Limited progress on the waterfront

In the 10 years since Rio, the outlook for the world's oceans has gone from bad to worse. Collapsing fish stocks provide a stark reminder that when a long-established ecosystem is disrupted, human livelihoods are among the casualties.

While overfishing and pollution continue to be key pressures, the increase in water temperature due to climate change and the related extremities in El Niño events could spell disaster. Fisheries that survive their encounter with the industry may well fall victim to changes in the food chain, disease patterns or habitat that arise from new environmental conditions.

Fish catches grew by only one per cent a year during the 1990s compared with three per cent in the previous decade, and the quality of fish caught has declined markedly. In some areas, once-thriving fishing industries have disappeared altogether.

On the Atlantic coast of Canada, for example, the closure of the once-prosperous Grand Banks cod fisheries has decimated whole communities. In the North Sea, the European Commission estimated recently that the fishing fleet was almost twice the size needed to catch the fish available. Disaster is imminent, the EC believes, as cod and hake are now being netted even before they are mature enough to spawn. Similarly, the Atlantic waters off West Africa have seen a sharp drop in catches in the past few years, with some species disappearing completely.

As catches get lighter, trawler fleets are spreading their reach into deep ocean waters beyond the continental shelf. In these chilly depths, fish growth is slower. As a result, the repercussions of overfishing are even more severe.

Dwindling stocks lead to rising prices. This, in turn, means that a growing share of the fish caught in developing countries is exported, depriving local people of a vital source of nutrition.

There is no doubt that trawler-fishing on the scale of the 1980s and 1990s is unsustainable. The question is whether politicians will intervene soon enough to allow stocks to recover--or whether the fishing industry will drive itself, and the marine species upon which it depends, to obsolescence.

To make matters worse, disturbing evidence is being pieced together of a dramatic loss of coral reefs, caused not only by overfishing but also by global warming, pollution, sedimentation and human interference. Depletion of herbivorous fish species that "clean" the algae off coral reefs can spell disaster, as can oil spills, industrial pollution and coastal development.

A recent report by the World Resources Institute estimated that more than half of the world's reefs are "potentially threatened" by human activity, with those in Southeast Asia most at risk. The WRI estimates that the number of animal and plant species associated with reefs probably exceeds one million.

One glimmer of hope is that regions which still have healthy, well-stocked fisheries and reefs still have time to learn from the mistakes of the past. The United Nations Environment Programme recently singled out Bangladesh as a country where, given the necessary safeguards, the fishing industry could grow sustainably, rather than following the depressing patterns seen elsewhere.

And while the world's coral reefs continue to disappear, valuable work is being done to raise awareness of where the threat is most severe, and to alert people to the activities that are doing the damage. After all, if the reefs and fisheries perish, everyone loses.