must be exterminated, photo by Kasey Carroll.

Kasey writes:

About ten seconds after I caught this, my fiancee’s uncle beat it repeatedly against the side of the boat. He said that it was an “intruder from outer waters and it must be exterminated because it eats all the perch eggs in Lake Eerie.” I’m sorry Peta. I didn’t do it.

See this bigger in her Things slideshow. The USGS Invasive Species Center page on the round goby says:

The round goby, Neogobius melanstomus, is a small, bottom – dwelling fish that was first found in the Great Lakes region in 1990. 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 are found in all of the Great Lakes with the greatest numbers in Lake Erie, Lake St. Claire and southern Lake Michigan. Many of the areas with round goby populations are best described as infested. Once round gobies arrive they can become the dominant fish species. Round gobies prefer rocky, shallow areas, but have flourished in a variety of habitat types. Regardless of the habitat, round gobies are very aggressive fish that compete with native fishes for food and space. Anglers who fish in areas with round gobies often find that the gobies steal their bait and appear to be the only type of fish in the area.

Round gobies can eat zebra mussels in addition to fish eggs, plankton, fish, and benthic invertebrates. Because zebra mussels are filter feeders that accumulate contaminants in their body tissues, round gobies that eat zebra mussels may be consuming a high level of contaminants. When a predatory fish such as a walleye eats a round go by that has fed primarily on zebra mussels, they may be getting a much larger load of contaminants than they would from eating other types of prey fish. This could put dangerous concentrations of contaminants into sport-fish at a much faster rate.

According to the MLive, there are now an estimated 10 million pounds of gobies in Lake Michigan alone! More information at round goby on Wikipedia and from the round goby page on Protect Your Waters. How do we stop their spread? Always follow the procedure to Stop Aquatic Hitchhikers!