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 the assistance of volunteer fly fishers, involved tallying, weighing, and measuring brook trout caught to aid Parks Canada in species monitoring.
Parks Canada informed CBC News that this year’s census is on hold because chain pickerel, accounting for 90% of fish caught in the park in western Nova Scotia in 2025, have significantly affected the brook trout population. The agency spokesperson mentioned that the presence of invasive chain pickerel has diminished the brook trout count reported in the census, making it insufficient for statistical analysis.
Originally introduced to Nova Scotian waters in 1945, chain pickerel infiltrated the province and were first spotted in the park in 2018. Once established in a water system, these predators rapidly dominate by consuming various species, including fish, reptiles, frogs, dragonflies, and even ducklings.
Efforts at Kejimkujik to control chain pickerel through fish barriers were hindered by flooding, rendering them ineffective in impeding the spread of the invasive species. Despite the setback, Parks Canada, with volunteer support, has successfully removed over 5,300 chain pickerel to date.
Anglers are obligated to retain chain pickerel at Kejimkujik, while native fish like trout must be released back into the water. The park will continue monitoring brook trout using alternative methods, such as the angler diaries program and deploying fyke nets annually to track native fish populations.
Conservationists like Ken Donnelly advocate shifting focus away from the park to regions not yet infested with chain pickerel. Trevor Avery, a biology and mathematics professor at Acadia University, studies the behavior of chain pickerel in Kejimkujik, emphasizing the predators’ voracious appetite and the necessity for population management strategies.
Despite the challenges posed by chain pickerel, Nova Scotia remains renowned for its brook trout fisheries, offering opportunities for anglers. The introduction of chain pickerel presents a dual challenge and opportunity for recreational fishing enthusiasts seeking new experiences in the region.