Date of Completion
Largemouth Bass, Fisheries Induced Evolution, Recreational Angling, Physiology, Genetics, Catch-and-Release, Angling
Dr. Jason Vokoun
Dr. Tracy Rittenhouse
Dr. Eric Schultz
Dr. Cory Suski
Dr. Amy Welsh
Field of Study
Natural Resources: Land, Water, and Air
Doctor of Philosophy
Recreational fisheries represent complex coupled human and natural systems subject to intricate feedback loops. These feedback loops can affect anglers, fish populations, and the ecosystem. I studied the effects of recreational angling on Largemouth Bass Micropterus salmoides populations, using unexploited populations for references. Exploited populations contained significantly more individuals with low metabolic rates than unexploited populations, consistent with predictions of fisheries induced evolution. Naïve individuals from unexploited and exploited populations had equal initial angling vulnerability in standardized trials. However, individuals from exploited populations learned lure avoidance faster than unexploited individuals. The cumulative number of catch events best predicted catch rates, and many individuals from both population types were never captured suggesting social learning may be involved with learned lure avoidance. Enhanced learning may be another mechanism through which angling selection affects fish populations.
Selection from recreational angling should decrease population vulnerability to angling, and is associated with ecologically important energetic phenotypes. I evaluated whether unexploited individuals could genetically contribute to an active fishery, and thus the potential for genetic management to restore phenotypes reduced in populations by selection from recreational angling. Parentage analysis revealed that individuals from exploited and unexploited populations contributed to an active fishery in proportion to their stocking frequency and sex ratios, suggesting that genetic management is a feasible management strategy.
To understand the current effects of recreational angling on Largemouth Bass populations I estimated the total number of catch events occurring in two lakes over two years. Catch was estimated by monitoring tournaments and from creel data collected by the Connecticut Department of Energy and Environmental Protection Inland Fisheries Division. Catch data and population size were utilized in a yield per recruit model to estimate the effects of length limits and catch-and-release mortality on population age and size structure. Modeling revealed that harvest rates estimated from creel data are likely too low for length limits to affect population structure, and even low rates of catch-and-release mortality are likely to significantly alter population structure. Creative management solutions that manage angler catch or effort are needed for high use fisheries with low harvest rates.
Hessenauer, Jan-Michael, "Contemporary and Historic Effects of Fishing on Largemouth Bass Populations, Using Unexploited Populations for Reference" (2015). Doctoral Dissertations. 979.
Available for download on Sunday, December 09, 2018