Smallmouth bass eating round gobys

Round Goby

Round Goby, photo by Dave Brenner, Michigan Sea Grant

The Great Lakes Echo reports that although a study has found that invasive round goby are “one of the most successful aquatic invaders” ever in the Great Lakes, smallmouth bass appear to be feasting on gobies:

25 years after their discovery in the Great Lakes, “we’re not documenting specific harms from gobies,” Popoff said, referring to feared environmental, economic and human health concerns.

In fact, there are indications of possible benefits from their presence, he said. For example, “we are seeing amazing smallmouth bass,” as well as some “amazing walleye,” while lake trout have modified their diets from sculpin to round gobies.

One possible exception, according to Popoff, is a decline in sculpin population as documented in Lake Michigan’s Grand Traverse Bay because they compete with round gobies for space and food. However, scientists haven’t determined whether the lake’s overall sculpin population is down or whether they’ve merely moved to deeper areas with fewer round gobies.

…However, the study found the round goby is now a widely available food source for many native fish because of its “extreme abundance, tolerance to a variety of habitat conditions and relatively small size.”

In lakes Erie and Ontario, round gobies accounted for 75 percent of the smallmouth bass diet, Crane said. If all other species have maintained stable populations, that means the bass are putting less pressure on other food sources.

Nice to see the Great Lakes winning a battle – read on for lots more.

View the photo background big and see more in Michigan Sea Grant’s Aquatic Invasive Species (AIS) slideshow.

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