The Influence of Spawning Habitat on Round Goby Egg Predation for Broadcast Spawning Species

Egg predation by Round Goby is a commonly referenced concern associated with their recent invasion of the Great Lakes. Surprisingly, few empirical studies have investigated Round Goby as egg predators.  Nest building species (e.g. centrarchids) are known to resist egg predation due to nest protection; however, broadcast spawners may have greater susceptibility to predation as they do not guard their eggs. Additionally, broadcast spawning species vary significantly in their spawning habitat that may affect Round Goby egg predation outcomes. This study will examine how differences in spawning habitat influence Round Goby egg predation rates on four different broadcast spawning species. A laboratory experiment will be used to investigate Round Goby egg predation rates on White Sucker, Walleye, Northern Pike, and Muskellunge eggs in six different habitat treatments. A complementary field study will quantify density, distribution, and diet of egg predators in known spawning locations. Field comparisons of these four species will be used to determine the extent of egg predation in known spawning habitats. Laboratory and field observations will quantify habitat-specific egg predation risk by Round Goby among these four broadcast spawning species, helping managers to better understand the effects of the invasive Round Goby on native sportfish.