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Broad issues on the State of the St. Lawrence
Progress report and future outlook for improving environmental monitoring
Aquatic invasive species: the "star candidates" on the new millenium
Day 2 (Wednesday, June 14, 2006, 1:00 p.m.)
Moderator: Michel Gilbert, Fisheries and Oceans Canada
Panellists:
Claude Lavoie, Université Laval
Chris McKindsey, Fisheries and Oceans Canada
Yves de Lafontaine, Environment Canada
Marcel Bernard, Ressources naturelles et Faune
Québec (Natural Resources and Wildlife Quebec)
Panellist Presentations
Claude Lavoie, Université Laval
In collaboration with Environment Canada, work is underway to inventory and monitor invasive plant species in the St. Lawrence wetlands. Water level fluctuations are an issue for the propagation of these species. It must be emphasized, however, that the invasion of aquatic plants may be a symptom of a more deep-rooted environmental problem of a physicochemical nature, such as an increase in nonpoint-source pollution, which fosters the proliferation of aquatic plants, some of which are invasive. Controlling invasive species requires knowledge of the true causes for the invasions.
Chris McKindsey, Fisheries and Oceans Canada
The Gulf of St. Lawrence is now home to approximately 40 invasive species; those of greatest concern are the green crab and a green alga commonly known as dead man’s fingers or oyster thief, scientific name Codium fragile. The thick growth it produces on the shells of oysters or mussels can prevent them from filter feeding. The oyster thief can trap gas bubbles in sufficient quantity to lift and float shellfish away. Observed in the region since 1996, the green alga is infesting shellfish, both wild and farmed, on Prince Edward Island and the Gulf shores of Nova Scotia and New Brunswick. It was observed on the Magdalen Islands for the first time in 2003. The green crab (Carcinus meanas), first observed on Nova Scotia’s Gulf shore in 1995, has spread to southeastern New Brunswick, the eastern shore of Prince Edward Island, and, recently, to the Magdalen Islands.
Yves de Lafontaine, Environment Canada
The invasive species problem is not new, but it has been raising serious concerns for the past 15 years or so. Previous species introductions were intentional, such as in the case of carp, which is today considered a nuisance species. The Great Lakes are home to over 170 non-indigenous species and the St. Lawrence has 86 of them, most of which were first introduced into the Great Lakes. We can confirm that two-thirds of these species were introduced by commercial navigation. The most problematic species are the zebra mussel, the round goby, the Chinese mitten crab, the tench, and the water chestnut. Little is currently being done to prevent the introduction of invasive species. With respect to control, the water chestnut is the subject of an eradication program in the Richelieu River. Very few tools exist for documenting, educating or increasing awareness about this subject, at least in French. The lack of a risk and impact analysis is preventing us from assessing the severity of this problem.
Marcel Bernard, Ressources naturelles et Faune Québec
Inland freshwater work is underway to inventory Myriophyllum spicatum (Eurasian water-milfoil) in Laurentian lakes that are home to lake trout. Since 2001, the Ministère des Ressources naturelles et de la Faune, with its partners, has been working to reduce the species’ density by removing water chestnuts from the Rivière du Sud. In addition, to prevent the species from propagating and in order to be able to intervene quickly, the Ministry is inventorying water chestnuts in streams adjacent to the Rivière du Sud. The propagation of the tench, first observed in 1995 in the upper portion of the Richelieu, is also being documented. Since 2003, the Government of Quebec has been participating in the Aquatic Invasive Species Task Group, which is working to achieve the implementation strategy for the Canadian Action Plan to Address the Threat of Aquatic Invasive Species. Quebec has taken steps to implement effective regulations on the use and sale of exotic species.
With aquatic invasive species, there is very often a considerable
time lag (up to 20 years) between the introduction of a species
and when it is first sighted. In such cases, it can be complicated
to trace the source or assign blame to those responsible for an
introduction.
It may take a long time for a species to become established. This
is the case with a number of invasive plants, including the common
reed. This species was introduced around 1916 and became invasive
in the 1960s due to environmental disturbances such as the construction
of Quebec’s highway system. Invasions are frequently the result
of triggering events, leading us to believe that the invasion of
exotic species is symptomatic of a more profound change in the ecosystem.
For example, inputs of nutrients to an aquatic environment foster
the proliferation of plants, including exotic species.
Although a great deal remains to be done, regulatory advances have been made. The sale of certain live species is being regulated, as is the use of certain species as bait fish.
Increasing amounts of energy and funds have been invested in the invasive species issue over the past few years, but some stakeholders wonder about the actual impact of exotic species on native ones. Researchers agree that at this stage, little has been documented. The harm that exotic species could cause to the biodiversity of a given environment is sometimes debatable. Moreover, questions must be asked about the cause for a species’ invasion to realize that biodiversity is sometimes threatened by an underlying problem . It is even possible that the introduction of exotic species may have certain positive impacts, such as increased diversity of a given environment or an abundance of prey (e.g. round goby) for aquatic wildlife, but it remains to be seen whether these impacts are harmful to indigenous species. However, it is recognized that the introduction of some exotic species has proved to be disastrous, as with green crabs on the American East Coast or perch in Africa’s Lake Victoria. There are numerous exotic species, but only some of them tend to be invasive and to become a nuisance, as much for biodiversity as for use.
One of the primary ways in which exotic species are introduced is through the ballast water of ocean-going vessels. Indeed, a regulation dealing with the management of the ballast water of vessels entering Canadian waters is about to come into effect to limit the introduction of exotic species. Another pathway for exotic species is the sale of invasive plant species for horticultural purposes. To limit the introduction of nuisance species in the absence of a regulatory ban on the sale of all invasive exotic species, horticultural business people and consumers alike need to be made aware of the problem.
Community involvement may be very beneficial in responding to those aspects of the issue that are removed from monitoring proper. For example, many communities are interested in participating in control measures, but do not always know where to start or what the priorities for action should be. A number of priorities have been defined: creation of outreach tools to combat these species, careful cleaning of vessels, and avoiding planting or transplanting invasive plants. These are all ways of limiting propagation, but thought must be given to every possible vector. The Internet also provides information on control methods, but they are not always translated for a Francophone clientele.
A comment was made about establishing invasive species alert networks. A number of monitoring activities now underway could include an invasive species watch network. For example, the fish monitoring network of the Ministère du Développement durable, de l’Environnement et des Parcs (Quebec Ministry of Sustainable Development, the Environment and Parks) is also used to detect aquatic invasive species during fish sampling. We could take advantage of existing monitoring networks to establish an invasive species alert network.
One last comment was made about the real issue of invasive species. Diversity has always been seen as an asset, and the globalization of genetic heritage is not a bad thing in and of itself. We do, however, need to question the actions we take that lead to the introduction of devastating exotic species, and about the changes at play in an ecosystem before these species are even introduced, to check whether or not we are giving appropriate consideration to the matter.
Date modified: 2008/05/01 – Important Notices
