Magazine article Science News

Shrinking Fish Can Get Big Again, but Such Reversal May Take Time: Study Suggests Managers Should Consider Fishing's Effects

Magazine article Science News

Shrinking Fish Can Get Big Again, but Such Reversal May Take Time: Study Suggests Managers Should Consider Fishing's Effects

Article excerpt

People can reverse evolution when it comes to the effects of fishing on sea creature size, researchers say. Just don't hold your breath.

The common practice of catching only the bigger fish in a population becomes an evolutionary pressure for later generations to stay small and grow slow, says fsheries scientist David Conover of Stony Brook University in New York.

He and his colleagues now report a lab experiment on silverside fish that stops the shrinkage trend and nudges the population's fish back toward larger sizes. Changing the direction of the selective pressure by eliminating the "take the big ones" rule brought a noticeable size increase within five generations, Conover and his colleagues report in a study released March 3 in Proceedings of the Royal Society B.

"It's the first experimental demonstration of reversing fisheries-induced evolution," Conover says.

Fisheries biologist Mikko Heino of the University of Bergen in Norway calls the work very interesting and important. The results support predictions that any recovery will be slower than the evolutionary effects of fishing, he says.

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Theorists have debated whether populations could recover from the size effects of fishing, Conover says. One argument states that natural selection might be too mild to push back hard enough to restore size on a human timescale.

To experimentally address the question, Conover and his colleagues caught hundreds of silversides (Menidia menidia) in Great South Bay, N. …

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