VIENNA - Industrial-scale fisheries have not only sapped the world's fish stocks but also changed the species' evolutionary course, exacerbating the effect of overfishing by producing smaller and less fertile fish.
Scientist Ulf Dieckmann also said that overfishing and the practice of throwing lower-quality fish back into thesea to raise the value of fishing quotas might explain the massive drop in population.
"Human activity had a possibly irreversible evolutionary effect in just a few generations," said Dieckmann, a member of a group of scientists who wrote a comment in the journal Science on managing fish stocks.
"We are running up a Darwinian debt that future generations will have to pay back."
Some 15 years ago, cod stocks in the Canadian Grand Banks in the northwest Atlantic collapsed, bringing down the fishing industry there.
Looking at data from the past few decades, the scientists found that increased mortality caused by overfishing had favoured fish that matured smaller and earlier, yet also carried far fewer eggs at their first reproduction.
Dieckmann said assessing the evolutionary impact could become an essential tool in managing fish stocks.
