Feeding and growth of lake trout fry on a diet of Hemimysis anomala

Session: 08a. - Restoration of Native Fishes

Emily Wimmer, Central Michigan University, [email protected]
J. Marsden, University of Vermont, School of Natural Resources, [email protected]
Scott McNaught, Central Michigan University, [email protected]

Abstract

Nearshore rocky reefs in the Great Lakes host a collection of species, including the invasive bloody red shrimp (Hemimysis anomala) and native lake trout fry (Salvelinus namaycush) The presence of Hemimysis on rocky reefs during spring, after lake trout fry emerge and begin feeding, could provide a needed food resource for rapid growth. To test whether juvenile lake trout will feed on Hemimysis, replicated laboratory feeding trials with 35-100 mm lake trout fry were conducted for 15 and 30 minutes, using varying Hemimysis sizes and Daphnia as a control. A growth experiment was conducted to determine if fry growth increased when fed a diet of Hemimysis in comparison to an assemblage of zooplankton. Percent Hemimysis consumed among time and prey types were analyzed using a 2-way ANOVA. Fry growth was analyzed using a General Linear Model. Fry consumption of Hemimysis was similar between prey sizes. Consumption of Daphnia was greatest and increased as feeding duration increased. Fry growth was greatest when fed Hemimysis in comparison to zooplankton. Our results suggest the presence of Hemimysis on rocky reefs when lake trout fry begin feeding could provide an abundant and nutritional food source.

1. Keyword
lake trout

2. Keyword
invasive species

3. Keyword
fish diets