Duluth researchers keep an eye on invading spiny water fleas


A lesser known aquatic invasive species has made its way into more than 50 bodies of water in northern Minnesota and continues to spread.

The Duluth News Tribune reports spiny water fleas were recently confirmed in Shagawa Lake near Ely.

The tiny crustaceans, native to Europe and Asia, were first introduced into the the Great Lakes in the 1980s due to ballast water discharged from ocean-going ships, according the Minnesota Department of Natural Resources.

In 1987, the invasive species was discovered in Lake Superior, but it's still unclear what the longterm effect of the infestations will be.

University of Minnesota Duluth researchers studying the Island Lake Reservoir near Duluth found that spiny water fleas have pushed out native water fleas in the last two decades and have eradicated spot-tailed shiner minnows in the lake, the newspaper reported.

Island Lake Reservoir has the highest population of spiny water fleas than any other single lake in North America.

So far, there's been no impact on sport fish, like walleye. Anglers have experienced some frustration when large populations clog fishing lines and other equipment.

The same invasive species laws pertain to spiny water fleas: boaters are required to remove all aquatic invasive species from equipment to prevent them from spreading to other waterways. Microscopic eggs are easily transferred in water or mud.

Here's a video from the North American Fishing Club about the "silent predator."

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