Starving sea life – from whales to puffins, tuna to seals – is being found all over the world’s oceans, as the food on which it depends is being fished out, startling new evidence shows. And much of the depletion, ironically, is caused by raising captive fish – for the table.
New figures from the Food and Agriculture Organisation show that the small fish on which birds and marine mammals feed have become the main target of fishing fleets since stocks of bigger fish have become exhausted. Four times as much of these “prey fish” are now brought to shore as half a century ago, and seven of the world’s largest 10 fisheries now go after them.
More than four-fifths of this catch does not go directly to feed people, but is ground up into fish oil and fish meal and increasingly used to raise carnivorous species such as salmon in fish farms. A captive fish needs up to 11b of food to put on a single pound in weight. And, as a result, there is less and less left for its natural predators.
“We have caught most of the big fish and are now going after their food,” says Margot Stiles, a marine scientist for Oceana, the leading international sea protection pressure group.
A new report by the group, Hungry Oceans, describes how “scrawny predators – dolphins, sea bass and even whales – have turned up on coastlines all over the world”, adding that scientists are finding them and seabirds “emaciated from lack of food, vulnerable to disease and without enough energy to reproduce”.