Invasive Species

Harmful alien species have invaded Ontario. They are a menace to our environment, our economy and even our health.  To learn more about invasive species visit

With over 180 non-native species already established in the Great Lakes, preventing the spread may seem like an overwhelming task.  Yet, there are some simple things you can do to stop their spread.  

Any watercraft has the potential to spread invasive species between lakes, rivers and streams.  You can avoid contributing to the spread of invasive species by taking the following steps with you watercraft:

  • Clean your boat and gear
  • Drain before you leave
  • Dry or disinfect
  • Avoid running the engine through aquatic plants

For more details visit

See FOCA's "A Shoreline Owner's Guide to Invasive Species"  for the best practices.

Visit to learn about other steps anyone can take to stop invasive species.

Spiny Waterfleas are one example of an invasive species.  They are small aquatic predators native to Eurasia. The first report of spiny waterfleas in North America was in Lake Ontario in 1982. Since then, they have been found in all the Great Lakes and in more than 100 inland lakes in Ontario, including Wood Lake.  They move to deeper, cooler waters during the day and swim towards the water surface at night to feed. They can multiply very quickly and their eggs can survive through the winter on lake bottoms and can be transported long distances on boats or equipment if they stay moist.

Researchers believe that spiny waterfleas are the greatest threat to the biodiversity and structure of native zooplankton communities on the Canadian Shield since acid rain.  Because their main diet is zooplankton, they reduce food supplies for small fish and the young of sport fish such as bass, walleye and yellow perch.  They are easily spread between waterbodies on angling equipment and bait buckets and in live wells and bilge waters.  Spiny waterflea introductions result in an average 30 to 40 per cent decline in native populations of zooplankton.  Their tail spines catch on fishing equipment, making it difficult to reel in lines.

If you have questions about spiny waterfleas, visit, the source of the above info.