Kevin L. Pope
Date of this Version
Park, A. P. 2017. Assessing Relationships Between Angling Effort and Larval Trematodes in Small Bluegill. M.S. Thesis. University of Nebraska. 163 pp.
I wanted to determine if catch-and-release angling increased larval trematodes in small (50-160 mm) bluegill (Lepomis macrochirus). I used angling effort as a proxy for amount of catch-and-release angling. I assumed bluegill assessed, due to their size and age, experienced catch-and-release events. I assessed larval trematode intensity, black spot (Crassiphiala bulboglossa), and white grub (Posthodiplostomum minimum centrarchi), in 750 bluegill. The first objective was to quantify the association between angling effort and reservoir area. Angling effort and reservoir area were positively correlated. The second objective was to determine if angling effort, reservoir area, bluegill age, and total length affect larval trematode intensity. I hypothesized that angling effort would positively affect larval trematode intensities, allowing larval trematode intensity to be an index of angling effort. Reservoir area, bluegill age, and total length were influential on larval trematode intensity; reservoir area and total length were negatively correlated, and bluegill age was positively correlated with larval trematode intensity, whereas angling effort was both negatively and positively correlated with larval trematode intensity. The third objective was to determine if angling effort, reservoir area, bluegill age, total length, and larval trematode intensity affect condition of bluegill. I hypothesized that increased angling effort and increased larval trematode intensity, and associated stressors from both variables, would decrease condition of fish. Reservoir area, total length, and larval trematode intensity were influential on condition factors, and angling effort and bluegill age were partially influential; reservoir area, bluegill age, and larval trematode intensity were positively correlated with three condition factors (viscerosomatic and hepatosomatic indices, and Fulton’s condition factor), whereas the angling effort and total length were positively and negatively correlated with condition factors. Overall, the effects of catch-and-release angling activities provide limited support for the hypotheses I put forth, indicating that larval trematode intensity is not a viable indicator of angling effort.
Advisor: Kevin L. Pope