Feeding behavior of juvenile Lake Trout on Hemimysis anomala and Daphnia pulicaria

Session: Poster Session

Scott McNaught, Central Michigan University, [email protected]
Starr Walker, Central Michigan University, [email protected]

Abstract

Hemimysis anomala, a recent invader of the Great Lakes, is present on rocky reefs where lake trout fry emerge and begin feeding. Previous research has shown that lake trout fry are able to consume Hemimysis but suggest that consumption rates may be limited by handling time and satiation. We conducted laboratory feeding trials with juvenile lake trout (80-100 mm) to determine how prey size affects foraging behavior and satiation. Replicated feeding trials were conducted for 30 minutes using small (<5.0 mm) and large (>5.0 mm) Hemimysis and Daphnia as a control. Video recordings were reviewed and analyzed for attack rate, capture success, ingestion success, and the duration between the ingestion and next attack. Data were analyzed with a nested ANOVA . Attack rate was highest for small Hemimysis. Capture success was greatest for Daphnia and decreased with increasing Hemimysis size. Our results indicate that juvenile lake trout are limited by handling time and satiation when feeding on large Hemimysis.