The effect of shelter availability on foraging in Atlantic salmon (Salmo salar)

• Main Author: Therrien, Christian A
• Format: Text
• Language: English
• Published: Scholarship@Western 2018
• Subjects: Predator-prey ecology; perceived predation risk; shelter use; foraging; growth; species reintroduction; fisheries management; Salmo salar; Aquaculture and Fisheries; Behavior and Ethology; Atlantic salmon
• Online Access: https://ir.lib.uwo.ca/etd/5847; https://ir.lib.uwo.ca/context/etd/article/7853/viewcontent/CTherrien_M.Sc._thesis___final_REV.pdf

Shelter is an environmental feature that provides protection from danger and its use is an important anti-predator behavior for juvenile Atlantic salmon (Salmo salar). However, how shelter availability influences the foraging of these fish in the wild is not well documented. I predicted that juvenile Atlantic salmon would alter their foraging behavior in a low shelter environment and that this effect would differ between individuals from two populations that are targeted for reintroduction into Lake Ontario. I measured the foraging activity of juvenile Atlantic salmon from the two populations while they were held in pens in a Lake Ontario tributary that differed in their shelter level. Particularly at midday compared to dawn and dusk, fish from both populations in high shelter had a foraging rate and activity level approximately 2.6 times higher than those in the low shelter. These differences in behavior had no noticeable association with diet or growth rate during the experiment. The two populations tested did not differ in their foraging behavior or growth based on the metrics tested. Overall, I found shelter can influence foraging behaviour of Atlantic salmon and these effects are conserved between populations.