The invaders among us: Zebra mussels well established in N. Channel

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The invaders among us: Zebra mussels well established in N. Channel

 

 

EDITOR'S NOTE: Beginning this week and continuing over the course of the summer, MaryEllen Shain, a student of conservation biology at Laurentian University and invasive species watch liaison with the Ontario Federation of Anglers and Hunters (OFAH), provides Expositor readers with a detailed look at the unwanted intruders that threaten our local ecosystem and provides tips on how to stem the alien tide.

 

 

Hi everyone! I hope you are all enjoying the fantastic weather this summer! My name is MaryEllen Shain and I am working on behalf of the Ontario Federation of Anglers and Hunters (OFAH) to deliver a message about an issue that is very important and often overlooked. While we are all taking advantage of the fun and excitement that our lakes have to offer, we can sometimes forget that these activates can leave our lakes vulnerable.

 

Invasive species are non-native plants and animals that are introduced into a new ecosystem, so they lack natural predators and therefore their populations are able to explode. They aggressively out-compete native species and their presence almost always leads to a transformation of the ecosystem that they invade. There are over 185 known invasives in the Great Lakes including round gobies, carp, rusty crayfish, Eurasian water milfoil and everyone's favorite, the zebra mussel. Invasive species cost the Canadian economy $15-34 billion dollars a year in damages and cleanup. Unfortunately, once an invasive species is introduced into an area, their removal is next to impossible. However, this does not mean that we should give up hope. There are still many inland lakes that remain unaffected and deserve our protection!

 

Since education is our best defence, it has become my job to inform and hopefully convince boaters, anglers, campers, swimmers and anyone else interested to take those steps necessary to keep our lakes clean. Over the course of the summer you will find me around the Island and North Shore posting signs, giving presentations, handing out brochures and writing future articles for the newspaper about different invasives in the area. I will also be taking water samples from a variety of lakes to identify possible contamination. If you would like me to test your lake, or if you have any other suggestions, comments or concerns, please call me at 348-0117. Or, you can call the OFAH invading species hotline at 1-800-563-7711.

 

 

Zebra mussels

 

Zebra mussels have been a particular concern for us Northerners for a long time. We have all seen their small sharp edges smothering the rocks on our beaches and many of us have suffered the battle wounds of this small freshwater clam without even realizing it. The zebra mussel has been responsible for clogging water intake pipes, is capable of sinking buoys, crashing natural fisheries and is the greatest threat to Ontario's most endangered species, the native clam.

 

The zebra mussel is a small (3-5 cm long) freshwater clam with a brown and cream-colored striped shell. Females can lay up to a million eggs each year beginning from when water reaches 12 C. Unfortunately for us, the cold, calcium-rich waters of Manitoulin Island serve as the perfect habitat for these invasives, yet our lakes contain no organisms which will keep their populations in check.

 

The microscopic larvae (called veligers) of the mussel are free-floating and can easily be transported by water currents, wind and wave action. Because the larvae are not visible to the naked eye, it is very important to ensure that no untreated water is transported from one lake to another such as in bait buckets and hauls. Each adult can filter up to one litre of water a day, increasing the clarity of the water and allowing more light to filter to the bottom. Weedy plants are then able to thrive, dramatically changing the nature of the lake's ecosystem. Between 1988 and 1991 the transparency of Lake Erie increased by 77 percent due to the action of zebra mussels, resulting in the elimination of natural fisheries. The more our lakes become infected with zebra mussels, the greater the overall threat to biodiversity.

 

Zebra mussels were first discovered in Lake St. Clair in 1988 and were introduced, like 70 percent of all other invasives, by the ballast water of large export ships from Europe. The spread of zebra mussels into our inner northern lakes can be attributed to adult mussels hitchhiking on recreational watercraft.

 

Lake Huron is infested. This is why it is important for us to practise precautionary steps to prevent the spread of zebra mussels to our inner lakes. If you are travelling from one lake to another, especially when you know the lake of origin is infected, please take extra care to protect the lakes we love and depend on.

 

Rinse with hot water of 50 C, spray with pressure of 250 psi, or dry for five days before moving your boat or other equipment to a new lake.