Overfishing represents the single greatest threat to marine life. It is estimated that more than 70 percent of the world's fish stocks are either fully exploited or not being managed effectively. A recent report published in the journal Science concluded that if present trends continue most species of fish will have disappeared altogether by 2048.
In the past some parts of the sea were inaccessible to fishermen, allowing fish stocks to replenish themselves by natural means. Technological advances now allow fishing boats to travel further than ever before and large ships have been built that can process enormous numbers of fish with ruthless efficiency. Industrial scale fishing proves devastating for the marine environment. Huge nets are dragged along the sea bed, destroying animal and plant life and threatening the delicate ecosystems that fish depend on for food and shelter. Fishing so indiscriminately leads to large amounts of by-catch. Up to 80 per cent of the fish caught by these huge trawlers are discarded because they are commercially useless.
The health benefits of eating fish have been widely publicised and nutritionists advise that we should eat oily fish high in omega-3 once or twice a week. Conversely, environmentalists warn that industrial pollution has led to the build up of toxins in the fatty tissue of fish that are hazardous to human health. The health benefits of oily fish therefore need to be weighed up against the potential risks and environmmental costs. The environmental food and farming group Sustain has identified ten species of oily fish that are sustainably caught and widely available in the UK. These are herring, kippers, pilchards, sardines, sprats, trout (not farmed), whitebait, anchovies, carp (farmed) and mussels.
The Marine Conservation Society have produced an excellent website that provides comprehensive information to help you to identify the fish that are most likely to have come from sustainable, well managed stocks. Greenpeace have identified a number of species to avoid that are commonly sold in supermarkets. These are Atlantic cod (except Marks & Spencer), plaice, tuna (except Skipjack), tropical prawns (wild and farmed), haddock, European hake, Atlantic halibut, monkfish, atlantic salmon (wild and farmed), swordfish, marlin, sharks (including dog fish and huss), skates and rays.
Jersey's Beresford street fish market in St Helier is probably the best place locally to buy the freshest fish from people who can tell you where they come from and how they were caught. Of the supermarkets, Marks and Spencer has been identified by the environmental campaign group Greenpeace (2006) as the market leader in sustainable seafood.