Jude, D. J., and J. Janssen, 1996.    Round Gobies: Cyberfish of the 90s, University of Michigan, Loyola University

Abstract from The Sixth International Zebra Mussel and Other Aquatic Nuisance Species Conference, Dearborn, Michigan, March 1996

Round Gobies: Cyberfish of the 90s

The round goby Neogobious melanostomus, after first being discovered in the St. Clair River in 1990, has now spread to four of the Great Lakes and is currently poised to enter Lake Ontario. Their epicenter of concentration in the Grand Calumet River and harbor, southern Lake Michigan, gives them access to the Mississippi River. These fish have apparently been spread throughout the Great Lakes through intrabasin freighter transfer via three possible modes: (1) discharged with ballast water, (2) cryptic behavior promoting hiding inside ship crevices or hoses, and (3) eggs laid on the underside of a ship and subsequently hatched at another port. Their original arrival here prior to 1990 was probably promoted by their ability to feed in the dark, made possibly by their unique lateral line and their ability to tolerate degraded water quality conditions. When gobies reach large sizes, their almost exclusive diet of mollusks (especially zebra mussels) gives them access to a currently underutilized food supply allowing them to expand their populations to high densities in areas of structure and abundance of zebra mussels. Like other exotics, their reproductive mode conveys an ecological advantage over our native fish species, since they are nest guarders and spawn every 20 days up to six times per year. They have severely depressed abundance of mottled sculpins in the St. Clair River in nearshore riprapped areas and forced remnants of the population into deeper water. There is diet overlap at small sizes, but their mode of impact on mottled sculpins appears to be disruption of spawning, either through aggressive defense of prime areas required by mottled sculpins for successful spawning or predation on eggs and larvae. We offer current evidence for this hypothesis from spring SCUBA research in the Grand Calumet River harbor. Reasons for alarm include: potential toxic substance transfer through food chains to man, possible impacts on deepwater sculpin, and ecological interactions in locations with low populations of zebra mussels.

Keywords: Round_goby, Basic_biology, Ecological_interactions
Product Type: Publication, Proceedings
User Type: General