Characteristics: (University of WI Sea Grant Institute) Although gobies belong to a family of fish with a worldwide distribution in both salt and fresh water, they had not been found in the Great Lakes prior to 1990. The round goby first turned up in Lake Superior's Duluth/Superior harbor area in 1995.
Round gobies are bottom-dwelling fish that perch on rocks and other substrates. They are aggressive fish and voracious feeders. They will vigorously defend spawning sites in rocky or gravel habitats, thereby restricting access of other less aggressive fish to prime spawning areas. Gobies also have a well-developed sensory system that enhances their ability to detect water movement. This allows them to feed in complete darkness, and gives them another advantage over other fish in the same habitat.
Gobies also are capable of rapid population growth. They spawn repeatedly during the summer months, and each time, a female can produce up to 5,000 eggs. The males die after spawning.
In Europe, the diet of round gobies consists primarily of bivalves (clams and mussels) and large invertebrates, but they also eat fish eggs, small fish and insect larvae. In the United States, studies have revealed that the diet of round gobies includes insect larvae and zebra mussels.
Look-a-like: Although the Round Goby is not believed to exist in any Vilas County waters (as of August, 2007), anglers occasionally report having caught what they believe to be a Goby. Careful identification reveals a native look-a-like known as the Mottled Sculpin (Cottus bairdi).
Round Goby vs. Mottled Sculpin
The clearest distinctions between the two species are the
fused pelvic fin and spineless dorsal fin of the goby
Links to other sites:
Wisconsin DNR
Wisconsin Sea Grant
Minnesota Sea Grant
USGS
Links to PDF documents:
Science Daily article
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