Fifteen years ago, scientists discovered that heavy fishing can create “fishing-induced evolution” — the more big fish we pluck out of the sea, the smaller the adult size of each successive generation. But according to a new study led by SUNY Stonybrook fishery biologist David Conover, the process is reversible.
Conover worked with ten generations of captive silversides. For the first five generations, he removed the biggest fish to simulate overfishing; as expected, this removal of “big-fish” genes reduced the average size of the adults in each subsequent generation. For the next five generations, Conover removed fish randomly to see whether the adults would start to rebound to their former size. They did, but nature made up for just half of the size reduction that Conover’s simulated overfishing had caused. Conover does expect the fish to return to full size but estimates that it’ll take another five generations — in other words, the recovery takes twice as long as the injury.
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