Hit the road: assisted migration as population enhancement?

• Main Authors: Frechette, Danielle M., Bergeron, Normand, Dionne, Mélanie
• Format: Other/Unknown Material
• Language: English
• Published: 2015
• Subjects: poisson; migration; Atlantic salmon
• Online Access: https://espace.inrs.ca/id/eprint/4102/; https://espace.inrs.ca/id/eprint/4102/1/C2919.pdf

Assisted migration applies human intervention to allow fish to bypass migration barriers through volitional passage (e.g. fishways) or translocation. There is increasing interest in using assisted migration to enhance Atlantic salmon populations, under the hypothesis that colonization of previously inaccessible habitat by reproductive adults will increase available habitat, thereby reducing densitydependent effects on juvenile growth and survival. We are evaluating a translocation program on population productivity of the SainteMarguerite River (Québec). For three years, returning adults are being captured, transported by truck, and released upstream of a pair of impassable waterfalls. We will examine habitat use by adults following transport and assess spawning habitat choice on juvenile growth and development. We transported 12 adults in 2014 (2F, 10M) and 25 adults in 2015 (12F and 13M), which we tagged with acoustic transmitters. A high percentage of fish strayed downstream over the falls (42% in 2014; and 28% in 2015). Males moved greater distances, whereas females had a greater propensity to stray. Evidence of reproductive activity was obtained from fish telemetry, visual inspection, and electrofishing. Passive acoustic monitoring has proven ideal for tracking fish movements in a remote, gravelbed river. Our study will inform future translocation programs throughout Québec rivers.