![]() In some lakes, fisheries have not been largely affected while in others, there have been dramatic declines. In some systems, the amount of algae has declined by over 50 per cent, with reverberating impacts to fish and other species that ultimately rely on algae for food. When found in high densities, the mussels can have strong impacts over algae, which are the base of the food web. This means infrastructure such as docks, water intakes, boats and other solid surfaces are likely to be heavily impacted. Zebra mussel populations can reach very high densities (more than 10,000 mussels per square meter). While the degree to which lake ecosystems are impacted is highly variable, there is certainly cause for concern here. The impacts of zebra mussels have been well documented in lakes across Europe and North America. Why are they a concern for Lake Winnipeg’s ecosystem? Zebra mussels attached to a rock were caught on the fishing hook of a LWF supporter on Aug. Zebra mussels are often unknowingly transported by boaters or other water users who don’t realize mussels or veligers have attached to their equipment. This time-lapse map, from the United States Geological Survey’s Nonindigenous Aquatic Species (NAS) online information resource, shows the spread of infestation. They are currently found in more than 750 lakes in North America. By 1991, zebra mussels began to spread to smaller inland lakes in Ontario and the eastern United States. Within several years, zebra mussels spread throughout the Laurentian Great Lakes. They were found in a harbour in Lake Erie, most likely transported from Europe via transatlantic shipping. Zebra mussels first arrived in Canada in 1986. Does that mean that other lakes in Canada are infested? Adult mussels and their microscopic larvae (known as veligers) were found in five harbours within the south basin.īased on current information, it appears that this species arrived in Lake Winnipeg from North Dakota via the Red River.Ĥ. Zebra mussels were first reported to the Province of Manitoba in Lake Winnipeg in October 2013. One mussel can produce up to one million eggs during a single spawning season.Ģ. Zebra mussels are an aquatic invasive species (AIS) – meaning they are not native to our lake’s ecosystem – and they are able to multiple very rapidly. Unlike other mollusks, they have hair-like filaments called byssal threads which they use to attach themselves to hard surfaces such as boats, docks, water-intake pipes and even the shells of other mussels. Zebra mussels are D-shaped, fingernail-sized mollusks with light and dark brown stripes. Not widely used, but very safe.Īll three of these chemicals must be continuously applied in order to maintain effectiveness.Zebra mussels (Photo: The United States Geological Survey) Additionally, zebra mussels can sense the presence of chlorine in the water and close their valves and stay alive for up to three weeks. It also generates trihalomethanes, which are considered carcinogenic. This is the most effective and widely used control method, but can contaminate water and damage other species. ![]() It’s very safe for the environment (breaks down into oxygen and water), but only works well at discouraging zebra mussel colonization-not cleaning an infestation.Ģ. It should also be noted that putting a grating on the end of the pipe won’t solve the problem-the zebra mussels will simply colonize over it and clog it.Ĭurrently, zebra mussels growing in water intake pipes are controlled by a few methods (all chemical), each with ups and downs:ġ. Zebra mussels colonize the edge of these pipes and eventually completely block off flow. ![]() Factories, power plants, and water treatment plants all have water intake pipes. ![]()
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