overfishing

Fishing at rates that exceed the sustained-yield cropping of fish species, resulting in a net population decline. For example, in the North Atlantic, herring has been fished to the verge of extinction, and the cod and haddock populations are severely depleted. In the developing world, use of huge factory ships, often by fisheries from industrialized countries, has depleted stocks for local people who cannot obtain protein in any other way. In their 2003 Global Environment Outlook Year Book, the United Nations Environment Program (UNEP) estimated that close to 75% of the world's fish stocks were already overexploited. See also fishing and fisheries.

Environmentalists have long been concerned at the wider implications of overfishing, in particular the devastation wrought on oceanic food chains. The United Nations Food and Agriculture Organization estimates that worldwide overfishing has damaged oceanic ecosystems to such an extent that their ability to support increased fish numbers is significantly reduced. With better management of fishing programmes the fishing catch could in principle be increased; however, it is estimated that, annually, tens of millions of tonnes of fish are discarded from fishing vessels at sea, because they are not the species sought.

The decisions governments have to make regarding the conservation of remaining fish stocks are not simply based on scientific recommendations but include economic and social factors too. The imposition of fishing bans can have an immediate and highly damaging impact on fishing communities and their support industries. In some cases, such as on the east coast of Canada and the USA and many ports along the North Sea coast, fishing quotas have permanently driven long-established fishing communities from their traditional livelihoods.

In 2003 a team of international scientists commissioned by the European Union recommended that a total ban be imposed in fishing for cod in the North Sea in 2004. They estimated that the minimum stock level to prevent the extinction of cod in the North Sea and Skaggerak was 156,000 tonnes, but that only one-third of this number actually existed. The EU responded to this recommendation by reducing fish quotas by 65% and 50% for hake and sole in particular. However, the quota for cod remained unchanged on 2003 levels in favour of a number of short-term measures designed to increase cod stocks by 30% in 2004.