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Zebra mussels a concern in local lake


In the last few years there has been a big push from the Manitoba government to recognize the aquatic invasive species (AIS) existing in our provincial lakes and to take precautions so that they don’t spread further, damaging not only our ecological systems but also our watercrafts.

The major culprit is the zebra mussel, which was first confirmed in Lake Winnipeg in the fall of 2013 and the Red River and Cedar Lake in 2015.

Unrecognizable to the human eye in their infancy, they can be inadvertently carried in small amounts of water transported by un-drained watercrafts, water-based aircraft and other water-based equipment, such as bait buckets.

The clam-like mussels grow to an adult size of one to three centimetres and can also strongly attach to equipment. Even once removed from the water body, they can survive seven to 30 days, depending on temperature and humidity.

 Because of these factors and the ease of which transfer from lake to lake can happen, last summer, Swan Valley Sport Fishing Enhancement Inc. (SVSFE) decided to be proactive and test a number of local lakes in both the Duck Mountains and Porcupine Mountains.

“Our area is not high risk but we initiated the process anyway,” said SVSFE Fisheries Technician Holly Urban, adding that anyone can take part and test any lake in the province.

“We partnered with the government on their AIS program. They provided samplers and we placed them in various lakes.

“The samplers consist of multi-size plates that are hung from the bottom of docks and other structures in the lake,” continued Urban, noting the mussels like dark areas. “We placed them under boat launch docks in all the lakes we tested.”

Although most results came back negative, concerns were raised with the sample taken from Singush Lake in the Duck Mountain Provincial Park.

“A sampler was set approximately one metre deep on July 23 and retrieved September 20,” said a spokesperson for Manitoba Sustainable Development. “During the analysis over the winter, a single damaged mussel was discovered.

“DNA testing conducted by the federal Department of Fisheries and Oceans confirmed the sample was consistent with the zebra mussel species.

“As a result of this finding, the provincial government is considering Singush Lake ‘suspect for zebra mussels’ and is implementing its early detection and rapid response protocol at this lake,” they continued. “This work will involve ongoing monitoring during the upcoming open-water season on Singush Lake and surrounding water bodies.”

The tiny but deadly crustaceans bring both ecological and social impacts. Lakes with established populations see an increase in aquatic vegetation and toxic algae blooms while noticing a decrease in walleye and whitefish populations and native mussel populations. They also alter the aquatic food web.

Socially, invaded lakes are often avoided as sharp shells will litter beaches and they will cause increased drag on boats and motor fouling, leading to expensive watercraft repair. These factors cause increased costs in food and utilities and damage to native fisheries leading to decreased tourism and recreational income.

Once zebra mussels become established, they cannot be eradicated, so it is extremely important to stop their spread.

The government and SVSFE are reminding residents to take an active role in preventing the spread by cleaning, draining and drying their watercrafts before they are moved between lakes. To aid this, the province will, as in prior years, have decontamination units and watercraft inspection staff located at high-traffic areas throughout the summer.

“If there is a true positive result in this lake in the future, then getting the early detection is a good thing,” said Urban. “It makes people aware that this is an issue and we need to be diligent. Especially in the Duck Mountains where the lakes are so close and people can easily go to two or three in one day.

“The education of how to properly drain and dry your equipment is important. Everyone sees the signs but, unfortunately, it’s not real enough until it’s often too late.

“This is a wakeup call that AIS are not just in Lake Winnipeg,” she concluded.

“It’s everyone’s responsibility to make sure AIS don’t make their way through the water bodies in Manitoba. We need to do the proper thing and contain the spread of it.”