From the AP:

A double whammy: stress and virus killing tournament fish

LA CROSSE, Wis (AP) _ Hundreds of dead bass have been collected from La Crosse-area river waters, days after a major fishing tournament was held in the region, a state official said.

Nearly all of the 582 bass were marked with a clipped tail fin, evidence they were caught and released during a bass-fishing tournament from July 12-15, said David Hobbs of the state Department of Natural Resources.

This is the second year that higher-than-normal fish deaths were reported in the area following the Wal-Mart FLW Stren Series Bass Fishing Tournament, which attracted 400 anglers.

Last year, most of the dead fish tested positive for largemouth bass virus, which can cause death when the fish is stressed.

The majority of the fish Hobbs collected this year were largemouth, and he said the stress of being caught, held in a livewell and released might be a factor in their deaths.

Tournament official Dave Washburn of FLW Outdoors, based in Benton, Ky., didn't immediately return calls by The Associated Press to his office over the weekend.

As part of an ongoing study, the DNR clipped the tail fins of the more than 2,000 bass caught and released during the four-day tournament. The research, conducted by the DNR and fishery biology researchers at the University of Wisconsin-Stevens Point, focuses on mortality rates in bass-fishing tournaments.