Date of Award


Access Control

Open Access

Degree Name

Great Lakes Ecosystem Science


Great Lakes Center


Dr. Randal Snyder

Department Home page

First Reader

Dr. Randal Snyder

Second Reader

Dr. Christopher Pennuto

Third Reader

Dr. Alicia Perez-Fuentetaja


North-temperate fishes are subject to significant changes in abiotic and biotic conditions across seasons, which are likely reflected in temporal differences in energy dynamics, reproductive investment, and diet. This study explores seasonal changes in body lipid content, female reproductive investment (GSI), body condition (Fulton’s K), and diet in brook sticklebacks (Culaea inconstans) in Western New York. I expected body lipid content and body condition would decline during the breeding season reflecting energy expenditure for reproduction, and these parameters would increase in the summer and fall prior to the onset of winter. Based on previous studies, I also expected the diet of sticklebacks would vary seasonally, reflecting a broad and flexible feeding strategy. GSI of female brook sticklebacks was highest during the spring, declined and remained low during the summer, and gradually increased during the fall; Fulton’s K showed a similar pattern. In contrast, body lipid content increased during the spring in male and female sticklebacks before declining in the summer and increasing in the fall, and Fulton’s K overall was not a reliable predictor of female body lipid. The diet of brook sticklebacks was broad in terms of the number of taxa consumed but was focused primarily on aquatic insects and crustaceans. The feeding strategy was seasonally variable, expressing a generalist feeding strategy in the spring and more specialized in the summer and fall. An enhanced understanding of prey fish energetics may aid in informing the management and conservation of native freshwater fish communities, sport fisheries management, and waterfowl conservation.