April 15, 2009

Genes cause problems for largemouth bass

A 20-year U.S. study shows some largemouth bass inherit a vulnerability to being caught, researchers said.

The University of Illinois study started in 1975 at a state park. Researchers say anglers had to put each fish that was caught into a live well on their boat. The fish were tagged to keep track of how many times each was caught and all fish were then released.

We kept track over four years of all of the angling that went on, and we have a total record -- there were thousands of captures, said David Philipp, an ecology and conservation researcher. "Many fish were caught more than once.

Subsequent testing designed to identify fish as having a low or high vulnerability to being caught continued for several generations during the course of the 20 year experiment.

As we had predicted, vulnerability was a heritable trait, he said, noting that with each generation, the difference between lines in angling vulnerability grew even larger.

The potential for angling to have long-term evolutionary impacts on bass populations is real, he said. If we truly want to protect this valuable resource into the future, then we need to understand that and adjust our management strategies.

The research is detailed in the journal Transactions of the American Fisheries Society.