Over-fishing: Fewer eggs, smaller fish

Jan 19, 2006

A University of California-Riverside study suggests harvesting the largest individuals from a fish population introduces harmful genetic changes.

Graduate biology student Matthew Walsh and colleagues found removing the biggest fish over several generations causes the remaining fish to become progressively smaller, have fewer and smaller eggs with lower survival and growth, and have lower foraging and feeding rates.

"We have shown for the first time that many traits correlated with fish body-size may be evolving in response to intense fishing pressure," said Walsh, who led the research project. "Our experiment is the only one to simulate the evolutionary impacts of harvesting in a laboratory setting."

Study results will appear in the February issue of Ecology Letters.

Copyright 2006 by United Press International

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