Originally from the Black and Caspian Sea areas of Eastern Europe, it is believed that this exotic species arrived in the ballast water of vessels coming into the Great Lakes. Since the first sighting in the St. Clair River, round gobies have spread to all of the Great Lakes and are working their way inland through the rivers and canal systems. Round gobies can reach up to 10 inches in length as adults, but usually they are less than 7 inches long in the Great Lakes. Females and immature male round gobies are a mottled gray and brown color. Spawning males turn almost solid black.
Round gobies have a soft body and a large, rounded head with eyes that protrude near the top.
Round gobies look similar to our native sculpins, but the two species can be easily separated by the fused pelvic fins on the underside of round gobies. Sculpins have two distinct pelvic fins, not one large fin. This fin can be used by gobies as a suction cup to anchor to rocks and other hard substrates during times of high water flow. Our scientists first worked with round gobies in the laboratory to determine the most effective electrical parameters and then participated in a small-scale field study to test the barrier in a more realistic setting. We were able to establish electrical parameters that successfully deterred passage of the majority of round gobies present.