Aquatic Invasive Species Monitoring
These are non-native species, whose introductions are considered to likely cause (or have already caused) damage to an existing aquatic ecosystem. The introduction and spread of these non-native species in our freshwater ecosystems is a world wide problem that is increasing in frequency and scale. In the Rouge River watershed the concern surrounding aquatic invasive species is primarily the threat they pose to local biodiversity. The introduction of these invasive species is generally considered one of the leading causes of native species becoming rare, threatened or endangered. As such, it is critical that these species are prevented access to habitats with species that are already “at risk”. The damage caused by aquatic invasive species can involve the elimination of native species or the change in its structure, function and overall processes of the ecosystem.
Aquatic invasive species without their natural predators have the potential to drastically alter habitat rendering it inhospitable for native species. Aquatic invasive species spread in a number of ways but primarily by human transport. Many of these species have already been responsible for significant devastation of some native fish species and fisheries in Canada.
Within the Rouge River watershed there are three aquatic invasive species that are of primary concern: sea lamprey, rusty crayfish and round goby.
Sea lamprey are aggressive parasites that feed on fish. A single lamprey can destroy up to 18 kilograms (40 pounds) of fish during its adult lifetime. Currently the Great Lakes Fishery Commission, in cooperation with Fisheries and Oceans Canada and the U.S. Fish and Wildlife Service, spend millions of dollars annually to control the sea lamprey population in Lake Ontario. Ongoing control efforts are undertaken within the Rouge River watershed in the form of lampricide applications (TFM).
Rusty crayfish have been present in the watershed for a number of years and are of concern because of their aggressive nature and high metabolic rate. More aggressive than the native freshwater crayfish in the watershed, they out compete them for habitat and food resources. In addition, they eliminate native species through hybridization. They also shape the aquatic ecosystem by consuming the eggs and young of fish and can be quite devastating to native aquatic plant life.
Round gobies have spread rapidly within the Great Lakes since their discovery in 1990. They are very competitive and reproduce quickly. In addition to habitat domination, they will also eat the eggs and the young of native fish. Round goby are just entering the lower portion of the Rouge watershed as of 2007 and are of great concern to the health of the aquatic ecosystem.
