Zebra mussel predation by round gobies in the laboratory

The round goby (Neogobius melanostomus), a native of the Black and Caspian seas, has spread from the original point of discovery in the St. Clair River to Lakes St. Clair, Erie, Huron, Michigan, and Superior. Round gobies utilize a broad range of foods, but prefer zebra mussels (Dreissena polymorpha). Gobies 6-10 cm in standard length consume mussels up to 7 x 13 mm. Zebra mussels 4-13 mm long are eaten at rates averaging between 36 and 47 per day, depending on predator/prey size; zebra mussels smaller than 4 mm were eaten at rates exceeding 100 per day. Feeding rates averaged 5.4/hr in 140-minute trials. Individual and clumped zebra mussels were preferred over sphaeriid clams on both sand and gravel substrates.