Date of Award
5-25-2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Biology
First Advisor
Melissa Wuellner
Committee Members
Greg Sass; Julie Shaffer; Keith Koupal
Keywords
fish; ecology
Abstract
Lake McConaughy is an important socioeconomic reservoir in Nebraska and Walleye is the priority management species. Walleye have been stocked annually since 1989 to support the Walleye population, however, adult Walleye relative abundance has steadily declined since the early 1990s. Additionally, in 1986, Alewives were introduced to improve the growth and body condition of adult Walleye, which subsequently increased the population size structure. However, Alewives can have negative influences on the recruitment of other fish species through predation and competition. Although Alewives have been in this reservoir for nearly 40 years, there have been no evaluations on the influence of Alewife on the fish and zooplankton communities. The first objective of my study was to compare the contributions and economic cost of stocked Walleye fry and fingerling to the fall age-0 catch. Walleye fingerlings comprised >50% of the contribution each year, with fry contributing 28% and 20% in 2022 and 2023, respectively. Fingerlings cost less to stock compared to fry and were thus deemed the most cost-effective product to stock during both years of my study. The second objective of my research was to describe temporal and spatial trends in Alewife relative abundance and food habits in Lake McConaughy. Alewives were sampled from May – July of 2022 and 2023 and stomach contents were collected from up to 20 individuals per gill net. I collected 1,890 Alewife stomachs over both years of my study and did not find any evidence of Alewife piscivory. Alewives almost exclusively consumed zooplankton across my study period. My results suggest that Alewife predation is not a factor strongly influencing Walleye recruitment, but there may be the potential for competitive interactions between Alewife and at early Walleye life stages.
Recommended Citation
Zebro, Logan, "Assessing the Influences of Stocking and Introduced Alewife on Walleye Recruitment in Lake Mcconaughy, Nebraska" (2024). Biology Theses, Dissertations, and Student Creative Activity. 19.
https://openspaces.unk.edu/bio-etd/19