The dilemma of the concerned fish consumer grows more acute each day, it seems. Should you put your own health, enhanced by the goodness of oily fish rich in omega-3, before the wellbeing of the world's dwindling fish stocks?
Sales of fish oil supplements have soared, propelled by reports suggesting it can increase longevity and even improve children's behavior. Yet, environmentalists warn that stocks of many fish are over-exploited, and we should stop eating them. They say toxins such as cancer-causing dioxins and PCBs have built up in the fatty tissue of fish thanks to decades of industrial pollution of the seas.
So which way to turn?
At last the conflicting advice has been pulled together. In a report published this week, the UK food and farming organization Sustain has analysed information from seven authoritative sources -- the UK Food Standards Agency, marine conservation societies in the UK and Australia, the Royal Society of Chemistry and specialist organizations monitoring the oceans around the world -- to draw up a list of fish that are both sustainable and healthy. Top for health are oily fish high in omega-3s but generally free of contaminants.
The 10 fish that fall into this category and are sustainably caught and available in the UK are herring, kippers, pilchards, sardines, sprats, trout (not farmed), whitebait, anchovies, carp (farmed) and mussels.
Of these, sardines, pilchards and sprats have the highest concentration of omega-3 fatty acids. Tinned tuna contains very little because the fat has been squeezed out to be sold as animal feed. Fresh tuna is a good source of omega-3s, but is generally contaminated with mercury. Only pole-caught skipjack, yellowfin, albacore and bigeye tuna is sustainably fished.
Other fish that are safe and sustainably caught include striped farmed bass, white bass, pacific cod, dover sole, alaskan and pacific halibut, red mullet, cold-water (but not warm-water) prawns, tilapia and turbot. These are not, however, oily fish and while they have many beneficial nutrients and are recommended, they are not high in the omega-3 fatty acids that research suggests many of us need more of.
The list of fish that qualify on all counts is not long, but the report's editor, Jeanette Longfield, says "unless people change what they eat, and governments stop running scared of vested interests, we're simply going to run out of fish."
Since 1950, technological advances in fishing have resulted in annual catches increasing from 18m tons in that year to 95m tons in 2000. During the 1990s, this rapid growth tapered off as fish populations declined dramatically. The latest figures from the UN food and agriculture organization say 52 percent of commercial fish species are fully exploited, 17 percent overexploited and 8 percent depleted.
Intense industrial fishing such as trawling is highly destructive to the seabed. As nets are pulled across the sea floor, they can flatten reefs and aquatic plants, which are the basis for entire local ecosystems. It is not known whether trawled areas can ever recover. Despite this, the trend has been towards building ever bigger trawlers. The Atlantic Dawn, for example, is a "super-trawler" built for Ireland by Norway. It is the largest fishing vessel ever made and accounts for 15 percent of Ireland's fishing capacity. It can drag behind it a net twice the volume of London's Millennium Dome.