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Invasive Species: Non-Native Species in the Great Lakes-St. Lawrence Basin
- What is a Non-Native Species?
- Examples of Non-Native Species in the St-Lawrence-Great Lakes Basin
- How Are These Species Introduced?
- Where Do the Non-Native Species in the St. Lawrence Come From?
- What Are the Consequences?
- How Does the Future Look?
- How do we Prevent Them from Getting In?
- How Can You Help?
- In Conclusion
What is a Non-Native Species?
Any animal or plant found outside its normal range is said to be a non-native species. When a non-native (or nonindigenous) species is able to reproduce and maintain a population in an introduced environment, it is said to be “naturalized”.
To date, at least an estimated 163 non-native aquatic species have been introduced into the Great Lakes over the last 200 years. Of these, 85 have already been observed in the St. Lawrence River. Close to 60% of all introduced species belong to the plant kingdom, while some 40% are comprised of fish and invertebrates.
Breakdown of the different groups of aquatic non-native species in the Great Lakes–St. Lawrence Basin . Source : de Lafontaine et Costan, 2002.
Examples of Non-Native Species in the St-Lawrence-Great Lakes Basin
How Are These Species Introduced?
The introduction of non-native species into the aquatic ecosystems of the St. Lawrence and Great Lakes is linked directly to human activities around international trade. The principal pathways of introduction are:
- ship ballast water exchange
- presence of waterways
- trade in bait fish
- dissemination of plants imported for agriculture or ornamentation.
Where Do the Non-Native Species in the St. Lawrence Come From?
What are the Consequences?
The presence of exotic species can have sometimes devastating effects on an entire ecosystem, the biggest being changes in habitat and in indigenous populations. The repercussions are manifested in the population: competition, predation, sickness and hybridization. Some invaders can remain out of sight for a long time, after which they expand their range and reproduce to the point where they become serious nuisances.
Some introduced species can also bring about major socio-economic impacts requiring control and cleanup measures. For example, the economic costs associated with the presence of the Zebra Mussel in the Great Lakes–St. Lawrence Basin, since its introduction in 1985, is an estimated $5 billion.
How Does the Future Look?
A number of species introduced into the Great Lakes should reach the St. Lawrence within the next few decades and could become established where local environmental conditions are favourable. Climate change could also contribute to accelerating the introduction and transfer of unwanted species. In the absence of effective competitors or predators, the population numbers of non-native species could climb rapidly.
How do we Prevent Them from Getting In?
Some of the following hyperlinks are to sites of organizations or other entities that are not subject to the Official Languages Act. The material found there is therefore in the language(s) used by the sites in question.
Here are some of the existing management tools for combatting the introduction of non-native species to the aquatic environment:
- A Guide to Canada’s Ballast Water Control and Management Regulations. 2006.
- National Code on Introductions and Transfers of Aquatic Organisms, published in January 2002 in Canada, sets in place a mechanism for assessing proposals for the movement of aquatic organisms from one water body to another.
- Nonindigenous Aquatic Nuisance Prevention and Control Act, adopted in 1990 by the United States to control and prevent invasions of non-native species and to co-ordinate research and regional action plans and control measures.
It is possible to limit the abundance of certain non-native species that have already become naturalized. A pilot project is currently under way in Quebec to study a biological control method. It consists of introducing insects that feed exclusively on the leaves and young shoots of the Purple Loosestrife, a naturalized invasive plant, to stop its spread. Before it can be adapted to large-scale use, however, this type of control must undergo a stringent assessment process.
To prevent the invasion of the Water Chestnut into the northern portion of Lake Champlain, the U.S. asked the Government of Quebec to intervene under the Lake Champlain Management Plan Agreement. A campaign was organized by the Water Chestnut Partners Committee (Comité des partenaires de la Châtaigne d’eau) to remove the plants by hand from the Rivière du Sud in summer 2001. This committee is co-ordinated by the Ministère du Développement durable, de l'Environnement et des Parcs du Québec and made up of representatives of Ducks Unlimited Canada, the Centre d’interprétation du milieu écologique du Haut-Richelieu, Environment Canada, and the MRC of Haut-Richelieu. For more details on the project to eradicate the Water Chestnut (French only).
Environment Canada is participating in the development of an anti-fouling coating to keep Zebra Mussels from attaching themselves to underwater structures. Researchers are currently assessing its effectiveness and working to determine the environmental impact of this coating. Preliminary field tests showed that an elastomer-based coating reduced Zebra Mussel colonization by more than 88% more than three months after application. The results also pointed up the importance of factors like luminosity and substrate orientation and porosity, all of which can alter coating effectiveness and the presence of competing species.
How Can You Help?
Individuals are responsible for the introduction of many alien species to Canada. You can do your part to help prevent further invasions by following the principles described on the Website Hinterland Who’s Who of the Canadian Wildlife Service and theCanadian Wildlife Federation.
- The presence of non-native species in the Great Lakes–St. Lawrence Basin is directly associated with business activities and trade.
- All non-native aquatic species have an impact, great or small, on aquatic ecosystems.
- Once present and acclimated, these species are said to be naturalized and can no longer be eliminated. All we can do is try to control their numbers and limit the impacts of their presence.
Bernatchez, L. and M. Giroux. 2000. Les poissons d'eau douce du Québec et leur répartition dans l'est du Canada.Éditions Broquet Inc. 350 pp.
de Lafontaine, Y. 2005. First record of the Chinese mitten crab (Eriocheir sinensis) in the St. Lawrence River, Canada.Journal of Great Lakes Research 31(3): 367–370.
de Lafontaine, Y. and G. Costan. 2002. Introduction and transfer of alien aquatic species in the Great Lakes–St. Lawence River drainage basin. In Alien Invaders in Canada's Waters, Wetlands and Forests. Natural Resources Canada.
de Lafontaine, Y. and G. Costan. 2000. The Unfolding Story of the Zebra Mussel in the St. Lawrence River. Fact Sheet. Environment Canada – Quebec Region, Environmental Conservation, St. Lawrence Centre.
de Lafontaine, Y., G. Costan, and F. Delisle. 2002. Testing a new anti-Zebra Mussel coating with a multi-plate sampler: Confounding factors and other fuzzy features. Biofouling8(1): 1–12.
Dumont, P. and J. R. Mongeau. 1990. Bilan des efforts d’introduction de la Truite brune (Salmo trutta) dans les eaux de la plaine de Montréal, Québec. Bull. Fr. Pêche Piscic. 319: 153-166.
Parks Canada. 1998. Rapport d’atelier sur les espèces exotiques envahissantes. Compte rendu de l’Atelier tenu le 23 novembre 1998 à Saint-Jean-sur-Richelieu. Parks Canada, Service de la conservation des écosystèmes.
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