Use of external Indicators to Evaluate Stress of Largemouth (Micropterus salmoides) and Smallmouth (M. dolomieu) Bass at Tournaments

ABSTRACT

The popularity of catch and release tournaments targeting largemouth (Micropterus salmoides) and smallmouth (M. dolomieu) bass has continued to increase over the past few decades. In 2008, Lake Champlain hosted 95 tournaments, including several large-scale events hosted in Plattsburgh, NY. As in any catch-and-release fishery, released fish exhibit varying amounts and types of stress, potentially generating sub-lethal population-level impacts. Due to the large volume of fish that move through catch and release tournaments, blood chemistry analysis is generally outside of the temporal and financial constraints of tournament organizers. External indicators of stress can be used to determine stress levels in large numbers of fish. We adapted some of these indicators (e.g., wounding, response to stimuli) from research in marine and commercial fisheries to assess fish stress following weigh-in at Plattsburgh-based catch and release tournaments. Additionally, we collected data including fish measurements, lake temperature, fish capture locations, and information on tournament handling practices to determine which external factors influenced fish stress levels. Generalized linear models showed increased likelihood of elevated stress levels as a positive function of ambient lake temperature, fish size, and livewell transport distance. Comparison of results with existing research on bass stress are consistent with our models, indicating that external signs of stress can be used to evaluate black bass stress levels at catch-and-release tournaments.

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