Iceland cod fished nearly to extinction
by Debora MacKenzie
Fishing is causing cod to evolve faster than anyone had suspected it could, fisheries scientists in Iceland have discovered. This turbo-evolution may be why the world’s biggest cod fishery, the Grand Banks of Newfoundland, crashed in 1992 and has yet to recover. The Icelandic cod fishery, almost the only large cod fishery left anywhere in the world, is about to go the same way unless urgent conservation measures are applied, the scientists warn. Einar Árnason’s lab at the University of Iceland in Reykjavik is part of MADFish, a network of Nordic scientists studying molecular mechanisms of adaptation in fish. They have discovered a gene in cod, Pan I, that seems to govern the depth at which the fish live. Cod with the B form of Pan I live deeper down, except when they are on the shallow spawning grounds. Cod with the A form of the gene spend all their time closer to the surface. As the cod close to the surface are most likely to get caught, survival chances of fish with the A gene are only 8 per cent of those with the B gene. As a result, fish with the A gene are disappearing rapidly. …
