Farm rules slow fish evolution

by Rob Peters | February 25, 2008 at 10:14 pm

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Researchers worry that the constant harvesting of big macho alpha fish is leaving all the procreating up to the smaller guys. So in a few generations, all the fish will be shy little betas? If that's the case, evolution might take a while.

WASHINGTON (AP) -- Rules that allow only the catching of larger fish may encourage their replacement with slower growing, more timid varieties. That, at least, is the concern of researchers who studied test populations in two artificial lakes and report their findings in this week's edition of Proceedings of the National Academy of Sciences.

Peter A. Biro of the department of environmental science at the University of Technology in Sydney, Australia, explained that it's the fast-growing more aggressive fish that tend to get caught, removing them from the breeding pool.

That leaves reproduction up to slower-growing fish who are more timid, he explained in an interview via e-mail.