Delayed Mortality of Tournament-Caught Walleyes

Abstract

We quantified the delayed mortality of walleyes Sander vitreus during three tournaments (April–June 2003) on Lake Francis Case, South Dakota. Weigh-in procedures (e.g., air exposure of fish during weigh-in, distance traveled, and so forth) and lake conditions (wind speed and wave height) were also measured to investigate how these factors affected delayed mortality. Delayed mortality was similar for control and tournament fish during the April tournament but increased for tournament fish as lake water temperature increased. Delayed mortality was 0% for control fish, even when tournament fish experienced high mortality; thus, the mortality of tournament fish was attributed to the tournament. Tournament procedures were generally similar for all tournaments, except that anglers traveled farther during later tournaments. The higher mortality experienced by tournament-caught walleyes during the June tournament was probably due to warmer water temperatures (18–20°C). These results will allow fisheries managers to better predict the effects of delayed mortality on walleyes caught in tournaments.