Duluth researchers keep an eye on invading spiny water fleas

Publish date:
Updated on

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."

Next Up


Summer of 2012 was warmest on record in Duluth

There were no record-breaking hot days, but red thermometers steadily turned June through August of 2012 into the warmest season on the books in Duluth. Forecasters think a 14-month streak of above-normal temperatures will continue in September. As for rainfall, it's been pretty sparse since the deluge that flooded the region in late June.

Duluth man rescues swimmers caught in rip current

A former Carleton College swim team captain helped pull three people to safety Monday morning off the shore of Duluth's Park Point. The News Tribune reports Josh Meltzer swam out in potentially deadly rip currents to save the swimmers struggling to stay above the water.