Invasive species of fish under investigation in the Outaouais
Invasive species of fish under investigation in the Outaouais
The tench, an invasive species of fish originating in Europe, was detected in the Ottawa River this summer. Known for its tolerance for low concentrations of oxygen and able to survive in varied habitats, the fish could have a negative impact on certain other species, such as crayfish, snails, mussels and insects that inhabit shallow coastal areas with lots of vegetation. They could enter into competition with other species that also feed on invertebrates. Thierry Calvé, a biologist from the Ministry of Forests, Fauna and Parks (MFFP) explained that the species appeared in Quebec after the owner of a failed fish farm released them into the St. Lawrence River.
«After this introduction, the species spread in the St. Lawrence. In 2018, a tench was captured in Atocas Bay, close to the Ontario shore of the Ottawa River. In 2020, tench DNA was detected by the MFFP in the Ottawa River near Grenville as well as downstream of the Carillon Dam. Although the Carillon Dam is an obstacle to the dispersal of fish further up the Ottawa River, it is not impassible, as fish can pass through the lock. There is therefore a possibility that they will use this route to spread upstream,» said Calvé (translated).
« With its calm water and shallow coastline rich with vegetation, the Ottawa river is a suitable habitat for the tench,» he added (translated).
Since 2019 the MFFP, in collaboration with the Ministry of Natural Resources and Forestry, have been monitoring the Ottawa River for the tench and other invasive species. Techniques they use have included laying and lifting of nets, use of an electric boat and the collection of DNA present in the water. The surveillance operation will continue this summer. In the spring of 2021, a tench was captured in a tributary of the Ottawa River near Casselman Ontario. The specimen was examined by specialists from the MFFP, and samples were taken to determine more information about the fish.
Collaboration sought with anglers
The MFFP is asking that anglers on the Ottawa River notify them if they observe or capture a tench, to better document the presence of the fish in the Outaouais. If caught, the MFFP requests that they not be returned to the water but sealed in an airtight bag and frozen. They also ask anglers to record the date and the GPS location where the fish was caught, and send it along to Outaouais-Faune@mffp.gouv.qc.ca. A specialist from the MFFP will communicate with them about a safe way to send samples for examination.
The full (French-language) interview with Thierry Calvé is available here.
