The VOICE of Anglers and Hunters since 1928

New Invasive Species Threatens Northwestern Lakes

August 27, 2007

For Immediate Release

Increased presence of spiny waterflea mimics infestation in Minnesota

An aquatic invasive species known as spiny waterflea are spreading and becoming more prevalent in waters along the Canada-U.S. border in northwestern Ontario, has invaded the following water bodies over that last year: Rainy River, Rainy Lake, Namakan Lake and most recently, Lake of the Woods on the Minnesota side of the border.

“Invasive species, including spiny waterflea have a huge negative impact on our lakes and rivers, and in fact, can disrupt entire ecosystems,” said Francine MacDonald, O.F.A.H. Invasive Species/Aquatics Biologist. “Spiny waterflea spread by attaching to fishing lines, downrigger cables and anchor lines. They collect in masses that resemble gelatin with tiny black spots, and are difficult to distinguish individually because of their small size. They compete with young fish for a food source known as zooplankton which can change the dynamic of the lake ecosystem and reduce biodiversity,” noted MacDonald.

The State of Minnesota, which shares a border with Ontario, has also recently discovered spiny waterflea in several additional lakes and designated them as “infested waters”.

Boaters and anglers can help to limit the spread of this and other invasive species by following a few simple rules when moving between lakes or rivers. Remove any visible foreign plant or animal matter from boats, motors, anchors and downrigger lines; spray watercraft and gear with high pressure washers, or wash with water hotter than 40C or allow the vessel to dry for at least five days before placing it in another water body; drain water from live wells, bait containers and bilges; and dispose of unwanted bait in the garbage or freeze and salt for future use.

“While spiny waterflea have been found in southern Ontario lakes since the late 1980’s, their invasion of northwestern lakes is relatively recent. The fact that Minnesota has listed several new lakes as “infested waters”, including Lake of the Woods, has increased concern in Ontario about the introduction of these invaders into relatively pristine ‘invader free’ waters. Invasive species cause billions of dollars each year in damage to our ecosystems and to the economy. Anyone who participates in outdoor activities such as boating or fishing should take care not to facilitate the spread of these invaders to other waters. For a map of lakes in northwestern Ontario affected by spiny waterflea, for further information or to report a sighting, visit or call the O.F.A.H./M.N.R. Invading Species Hotline at 1-800-563-7711,” said MacDonald.

The Ontario Federation of Anglers and Hunters (O.F.A.H.), with 81,000 members and 655 member clubs across the province, is the largest nonprofit conservation organization in Ontario.


Francine MacDonald
Invasive Species/Aquatics Biologist
(705) 748-6324
Greg Farrant
Government Relations & Communications Manager
(705) 748-6324