Act of Cod

Something's fishy in the state of Iceland:

The Atlantic cod has, for many centuries, sustained major fisheries on both sides of the Atlantic. However, the North American fisheries have now largely collapsed. A new paper in the open-access, peer-reviewed journal PLoS ONE from scientists at the University of Iceland and Marine Research Institute in Reykjavik provides insights into possible mechanisms of the collapse of fisheries, due to fisheries-induced evolution.

Cod fishing is of highest intensity in shallow water in Iceland and it selects against genotypes of cod adapted to shallow water. The PLoS ONE paper reports a significant difference in Darwinian fitness (relative survival rate) between shallow-water and deep-water adapted cod. The shallow-water fish have only 8% of the fitness of deep-water fish. This difference can lead to rapid elimination of shallow-water fish in only a few generations with drastic effects on the population and the fishery.

Funny, everyone freaked out over the suggestion that codfishing be restricted to allow fish stocks to replenish themselves, fearing job losses. And now that there are so few cod left...the industry has collapsed and there were many job losses. Good one.

This same situation is playing out with other fish, especially bluefin tuna, as detailed in Richard Ellis' excellent 2008 book Tuna: A Love Story.