Over fishing has not only reduced the world’s fish stock with some species on the verge of extinction but has also changed the species’ evolutionary course, according to a new study. A group of scientists has written a comment on managing fish stocks in the journal Science published on Thursday.
According to scientist Ulf Dieckmann, overfishing and the practice of throwing lower quality fish back to the sea might explain the massive drop in fish population. Some 15 years ago, cod stocks in the Canadian Grand Banks collapsed, bringing down the fishing industry in the region. The same species is now under threat in north-east Atlantic off Norway and Russia. In the Canadian Grand banks, the fish stocks show little sign of recovery.
Studying data from the fisheries industry over the past few decades showed that overfishing had favoured fish that matured smaller and earlier and carried fewer eggs at their first reproduction. Earlier a typical cod caught in Norway took ten years to mature. Now it took the same species six years or even less to mature.
Scientists have warned that such evolutionary change triggered by human activities might be irreversible.
Source:reuters
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