No evidence of migration in a 4-year study of an at-risk migratory fish—the centenarian bigmouth buffalo (Ictiobus cyprinellus) of Saskatchewan

Abstract

The bigmouth buffalo (Ictiobus cyprinellus, Valenciennes 1844) is a long-lived freshwater fish native to North America that is listed as a species of special concern in its Saskatchewan-Nelson range. Little is known about their ecology and behavior, especially in the Saskatchewan Qu'Appelle River system where it faces multiple threats such as habitat fragmentation and competition with invasive species. In this study, we used acoustic telemetry to track the movements of 44 bigmouth buffalo throughout the Qu'Appelle River system in 2017–2019, and 2021, to monitor migration patterns from spring to fall and investigate if any of the five dams were impeding their ability to access either breeding or overwintering grounds. We found that bigmouth buffalo demonstrated minimal use of the river during this 4-year study, instead staying within the confines of a single lake year-round. Our results suggest that bigmouth buffalo in the Qu'Appelle River do not exhibit migratory behavior during nonflooding years. Considering their extended lifespan (>125 years), this could be attributed to their potential bet-hedging strategy for spawning primarily during flood years. The results indicate that bigmouth buffalo voluntarily remained within Buffalo Pound Lake throughout the study period. Whether this behavior was natural or was influenced by modifications to the system’s hydrology requires further investigation.

Keywords

• species at-risk
• SARA
• habitat fragmentation
• acoustic telemetry
• population monitoring
• migratory behavior