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Goby Population Found in Duluth-Superior Harbor

Krause kids with goby.

Goby-catchin’ kids. Cousins Cody and Tom Krause, and friend, display their catch and rig. The youths caught the largest number of round gobies ever found in the Duluth-Superior harbor and were able to identify the fish due to Sea Grant public education efforts through the media.

Two Superior, WI, teenagers discovered a thriving population of round gobies (Neogobius melanostomus), an exotic fish, in the Duluth-Superior harbor this summer.

“Unfortunately, this is the most significant confirmed report of a goby infestation in the Duluth-Superior harbor to date,” said Doug Jensen, Exotic Species Information Center coordinator for the University of Minnesota Sea Grant program. “This also shows that anglers, especially youth, are getting the message about exotic species. One of the teenagers said he remembered how to identify the round goby based on television news coverage and a recent newspaper article,” said Jensen.

Cousins Tom and Cody Krause (15 and 13 years, respectively) reported their finding to Minnesota Sea Grant in July, after reading a local newspaper article that described how scientists found nine gobies in the harbor during June, and included contact information.

As avid anglers, the Krauses often fish together for yellow perch. They caught 83 round gobies during one week in July near Barker’s Island Marina. They gave a sample to Sea Grant for confirmation.

“Anglers are often the first to find new infestations,” said Jensen. “We are concerned because this new infestation increases the potential for accidental spread by anglers to other waters.

“The other big news is that gobies now infest all of the Great Lakes,” said Jensen. “Lake Ontario was the lone hold-out until this month. Infestations in the first two North American inland lakes were also found this summer.”

Gobies are considered undesirable because they compete with native fishes for habitat, disrupt the aquatic ecosystem, and are a nuisance to anglers. The goby is an aggressive, small, bottom-dwelling fish that is mostly slate-gray, with frog-like raised eyes, a prominent black spot on the dorsal (top) fin, and a distinctive, fused, scallop-shaped pelvic (bottom) fin. Identification cards are available from Minnesota Sea Grant and can be ordered on our publications page and our free order form, under the exotics category (item X36).

Round gobies were first discovered in North America in 1990 in the St. Clair River near Detroit. They were introduced through ballast water discharged by transoceanic ships coming from the gobies’ native waters in the Caspian Sea and Black Sea in the Baltic region of Eurasia. Round gobies were first found in Lake Superior in the summer of 1995.

For more information about exotic species, contact Doug Jensen, 218.726.8712.

By Sea Grant Staff
September 1998

Return to September 1998 Seiche

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