Date of Award
Master of Science
Dr. Jill B. K. Leonard
Winter is a time of year of low temperatures and limited food availability. Brook trout (Salvelinus fontinalis) survival in winter is dependent on several factors including their condition after spawning in the fall and possibly their behavior in winter. Ice that forms during winter can potentially aid in survival by decreasing predation risk, decreasing stress, and acting as a thermal refuge. The emphasis of this project was to evaluate the relationship between movement patterns of brook trout and winter ice distribution. In the fall of 2017 and again in the fall of 2018, brook trout in a northern Michigan stream were collected by electroshocking. All fish had their length and weight measured, and fish over 100 mm were tagged with a Passive Integrated Transponder (PIT). Following tagging, fish were tracked and their locations within the field site were recorded as well as if they were in open water or under ice cover. In the spring of 2018 and 2019, electroshocking surveys were performed again, and tagged fish were measured for length and weight. Tracking surveys occurred biweekly and showed that brook trout used ice covered areas. Two movement groups were present, a sedentary group consisting of 90% of fish and a mobile group consisting of 10%. Surface covering ice was used by fish throughout all stages of winter. Recaptured brook trout did not demonstrate any statistically significant change in their Fulton’s condition factor. These results highlight the importance of specific surface cover during winter to brook trout behavior and their movement during winter.
Bejcek, Benjamin, "INDIVIDUAL VARIATION IN WINTER BROOK TROUT (SALVELINUS FONTINALIS) MOVEMENT IN A SMALL NORTHERN MICHIGAN STREAM" (2020). All NMU Master's Theses. 615.