Kejimkujik National Park in Nova Scotia has decided to halt its annual brook trout census due to the negative impact of an invasive species on the local ecosystem. The census, which commenced in the 1990s with volunteer fly fishers participating, involved counting, weighing, and measuring brook trout to aid Parks Canada in species monitoring.
Parks Canada informed CBC News that this year’s census is on hold because of the prevalence of chain pickerel, which constituted 90% of the fish caught in 2025 at the national park in western Nova Scotia. The agency stated that the brook trout population reported in the census is currently insufficient for statistical analysis due to the invasion of chain pickerel, which were illegally introduced to Nova Scotian waters in 1945 and appeared in the park in 2018.
Despite efforts to establish fish barriers, the spread of chain pickerel continued due to flooding, making it challenging to prevent their expansion. However, Parks Canada, supported by volunteers, has removed over 5,300 chain pickerel so far. These predatory fish are required to be retained when caught, while native fish species, including trout, must be released back into the water.
While the brook trout census is paused, Parks Canada will utilize alternative methods such as angler diaries and deploying fyke nets to monitor native fish populations in Kejimkujik. Conservationists are advised to shift focus to areas where chain pickerel have not invaded, as early intervention is crucial in addressing the issue.
Trevor Avery, a biology and mathematics professor at Acadia University, has been studying chain pickerel in Kejimkujik since their introduction. He highlighted the effectiveness of consistent fishing in managing the chain pickerel population. Additionally, Andrew Lowles, a resource manager at the Nova Scotia Department of Fisheries and Aquaculture, noted the historical significance of Nova Scotia’s brook trout fisheries and the recreational opportunities presented by chain pickerel.
The situation at Kejimkujik National Park underscores the challenges posed by invasive species and the ongoing efforts to mitigate their impact on the local ecosystem.
