The rapid spread of invasive smallmouth bass and chain pickerel and a changing Nova Scotia fishery

Abstract

In the 1940s, Smallmouth Bass (Micropterus dolomieu) and Chain Pickerel (Esox niger) were confirmed in 14 lakes collectively in southwest Nova Scotia. By 2025, Smallmouth Bass had been documented in 340 lakes, while Chain Pickerel had been reported in 180 lakes, representing approximately 34% of the province’s lentic habitats. The initial spread of Smallmouth Bass was facilitated by government-sanctioned stocking; however, over the past 80 years, the range of both species has expanded due to natural migration and illegal introductions. The increasing popularity of Smallmouth Bass and Chain Pickerel among anglers is reflected in annual catch statistics. While the spread of these invasive species has created additional angling opportunities, their introduction has significantly disrupted the natural integrity of freshwater ecosystems, permanently altering the landscape of the sport fishery. In response to this challenge, a range of strategies and policy changes have been implemented to address the expanding threat posed by aquatic invasive species.

Keywords:  brook trout, aquatic invasive species, fisheries management, rotenone