Invasive spiny waterflea found in Chukuni River



A non-native, invasive species of zooplankton known as the spiny waterflea has found its way into the Chukuni River and poses a real threat to the ecosystem of local waters.

“Researchers believe that spiny waterfleas are the greatest threat to the biodiversity and structure of native zooplankton communities on the Canadian Shield since acid rain,” says Toby Braithwaite, management biologist for the Ministry of Natural Resources and Forestry (MNRF) in Red Lake.

Spiny waterfleas feed on native zooplankton and, on average, cause a 30 to 40 percent decline in native populations of zooplankton.

“As such they reduce food supplies for small fish and young of sport fish (including yellow perch and walleye),” explains Braithwaite. “Spiny waterfleas can also affect recreational angling. Their tail and spines catch on fishing equipment, making it difficult to reel in lines.”

In September, the Red Lake MNRF confirmed the presence of spiny waterfleas in the Chukuni River, which connects the Red Lake and Gullrock Lake system, and has committed to monitoring the population and spread there, as well as in other lakes in the Red Lake district.

Braithwaite says it is difficult to determine how the spiny waterfleas found their way into the Chukuni River, but notes that they can be transported long distances on boats, fishing equipment, and floatplanes.

Spiny waterflea rely on water currents and wind to move long distances, and can multiple quickly both sexually and asexually.

The species was first found in North American in Lake Ontario in 1982, introduced to the Great Lakes through ballast water from ocean-going ships.

“The species, native to Eurasia (the combined continental landmass of Asia and Europe) has been found in all of the Great Lakes, more than 100 inland lakes in Ontario, Lake Winnipeg and the Winnipeg River in Manitoba,” explains Braithwaite.

The first step in preventing the spread of spiny waterfleas, says Braithewaite, is being able to identify them.

Spiny waterfleas have a single dark eye, four pairs of legs, and branched antennae used for swimming. They measure 1.5 cm, including a straight or slightly angled tail with one to three bars and a pointed end. Spiny waterfleas can be orange, blue, or green, and have a red stripe running half the length of the trail.

The next step is making sure all water vessels are thoroughly cleaned before entering a new body of water.

“Inspect your boat, trailer and equipment after each use and remove all plants, animals and mud before moving to a new water body. Drain water from your motor, live well, bilge and transom wells while on land,” advises Braithwaite. “Washing your boat with a pressure washer (at least 250 pounds per square inch) or hot water (at least 50 degrees Celsius) helps remove small invasive species that are often difficult to see, like spiny waterflea.”

Find out more about spiny waterfleas and other invasive species at

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