A fish tale that's true

This is the strange story of the California sheephead — a strikingly colored fish that swims in the kelp forests and can grow to nearly 3 feet long — as told to me by a marine scientist when I was training to volunteer at the local tide pools. To keep the sheephead stocks healthy, the state set a minimum size for those that could be caught. But over time, experts noticed that the average size of the adults was shrinking. It was an undesirable and unintended consequence of the rules: Smaller sheephead were thrown back into the water. Their DNA was thus more likely to be passed on in the marine gene pool. Sheephead were evolving before our eyes.

December 26, 2012