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. Since the 1990s, the census has been carried out by volunteer fly fishers who catch, weigh, and measure brook trout to aid Parks Canada in monitoring the species.
Parks Canada disclosed to CBC News that the census for this year is being suspended because chain pickerel, an invasive species, dominated the fish caught in the park in western Nova Scotia, accounting for 90% of the catch in 2025. The spokesperson for Parks Canada mentioned that the presence of chain pickerel has severely affected the brook trout count, rendering the data insufficient for the monitoring project.
Chain pickerel, which were illegally introduced to Nova Scotian waters in 1945, made their way to the park in 2018, rapidly establishing themselves and preying on various species in the ecosystem. Efforts to contain the spread, such as fish barriers, have been hindered by flooding.
Despite the challenges faced, Parks Canada remains committed to mitigating the impact of chain pickerel. Over 5,300 chain pickerel have been removed by Parks Canada staff with the assistance of volunteers. Additionally, chain pickerel caught at Kejimkujik must be retained, while native fish species, including trout, are released back into the water.
To continue monitoring brook trout populations, Parks Canada will utilize alternative methods such as the angler diaries program and deploying fyke nets in different water bodies within Kejimkujik. Conservationists suggest shifting attention to areas not yet affected by chain pickerel for more effective intervention.
Experts like Trevor Avery from Acadia University emphasize the importance of managing chain pickerel populations through strategies like targeted fishing. While chain pickerel pose a threat to the ecosystem, they also offer recreational opportunities for anglers in Nova Scotia.
The conservation efforts at Kejimkujik National Park underscore the challenges posed by invasive species and the ongoing need for vigilance in protecting native ecosystems.
