MUSSELS MAY BE RE-SHAPING GREAT LAKES SHORELINES

As you walk along many Great Lakes shorelines, you're likely to see many more shells. They are the result of the invasion of the lakes by zebra mussels and their cousins, the quagga mussel, two of the many alien invasive species which have invaded the Great Lakes. There are now millions of those creatures living in the lakes, introduced in the ballast of ocean going ships.

The sharp shells can be a nuisance to swimmers. They also can significantly change the nature of the lake bottom, affecting fish habitat and spawning. But mussels have an impact beyond changing the lake bottom. Mussels eat by filtering nutrients from the water. This is the same food source for many species of fish and other organisms. Overall, the impact is a reduction in the amount of food available native species. However, in near shore zones, where mussel populations dominate, nutrients may actually be trapped by the mussels, rather than moving out into deeper waters. When this occurs, mussels create an environment on the bottom that may be linked to water quality problems, such as algal fouling on rocky shorelines, off-tastes in drinking water and lethal outbreaks of botulism in wildlife.

Beyond leaving less food available for fish in critical near shore habitats, the mussels appear to be changing the natural process along the shoreline by holding materials near the shore. When the mussels die or violent storms occur, the stored materials can be transported out of the lake or downwards into deep sediments.

These ideas have been investigated for the first time in the east end of Lake Erie for the last three years by a group of scientists from University of Waterloo, National Water Research Institute of Environment Canada, and the Ontario Ministries of the Environment and Natural Resources, through various experiments and studies. The work, which was supported by the Government of Canada Great Lakes program funds and by a NSERC grant to University of Waterloo will finish field work in 2003.

For more information please contact Murray Charlton , National Water Research Institute

Other links:

http://www.on.ec.gc.ca/laws/coa/invaders-e.html
http://www.nwri.ca/nwri-e.html/