Don't cross contaminate our lakes


What are aquatic invasive species?

They are species introduced to an environment which originally is not their natural environment. This means they are out of their natural range. These species may come from the same continent, such as species from United States and introduced in Quebec. This is the case of rusty crayfish (picture 1). These species are called non-native.
Picture 1. Rusty crayfish (source: Maria José Maezo)
They may also come from another continent, such as species from Asia and introduced to North America like the zebra mussel (picture 2). These are called exotics. The non-native and the exotic aquatic invasive species are introduced accidentally or intentionally through various human activities. In Québec, there are many aquatic invasive species
that have become established. In the Outaouais region, there are six aquatic invasive species that are particularly worrying:

Where they come from?

The Great Lakes and the Saint-Laurent River are the main entry points of aquatic invasive species to Quebec. More than 183 species coming from different regions of the globe have become established in the Great Lakes! The aquatic invasive species are introduced in the Great Lakes and the Saint-Laurent River by four major vectors: 
  • The ballast water of merchant ships
  • Artificial circulation canals
  • Live organism trade
  • Recreational water activities (boaters, fishing, hunting, etc.)
Picture 2. Zebra mussels (source:
Today, with the increase of internationals trade, the ballast water released in the Great Lakes and the Saint-Laurent River by the merchant ships is the most important source of introduction of aquatic invasive species (picture 3).
Picture 3. Load and discharge of ballast water of merchant ships (source:
Once established in this new environment, the aquatic invasive species spread to inland waters such as rivers, lakes, streams, ponds, marshes and others. The species are spread via several pathways, the main ones are:
  • Boaters (boats, rowboats, canoes, kayaks, jet skis, etc.)(picture 4)
  • Fishermen and hunters (boats, fishing and hunting equipment, bait buckets, etc.)
  • Aquarium and horticulture (water gardens) markets
  • Seaplanes
  • The divers

Why are they harmful?

Aquatic invasive species are threatening for several reasons that affect everybody. They cause enormous environmental and economical damages. Damages are essentially:
  • Cottage water intakes block
  • Decreases in value of your waterfront property
  • Damages to boats, engines and to fishing and hunting gear
  • Choking of waterways and reduction of water use by boaters, swimmers and others


Picture 4. Mat of aquatic plants fixed to a trailer (source:
  • Reduction in number and diversity of sport fish
  • Premature aging of water bodies affected
  • Degradation of the natural beauty of our water bodies
  • Reduction of natives plants, fish, crayfish, birds, etc.
  • Decreases in biodiversity
For more information about aquatic invasive species and some awereness tools available for distributiion and display, contact Marie-Pier Tremblay. You can also consult the price list for the boat launches signs.

Price liste for the boat launches signs