Competitive interactions among multiple non‐native salmonids and two populations of Atlantic salmon

• Published in: Ecology of Freshwater Fish
• Main Authors: Houde, Aimee Lee S., Wilson, Chris C., Neff, Bryan D.
• Other Authors: Natural Sciences and Engineering Research Council of Canada
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2014
• Subjects: Almo; Atlantic salmon
• Online Access: http://dx.doi.org/10.1111/eff.12123; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Feff.12123; https://onlinelibrary.wiley.com/doi/pdf/10.1111/eff.12123

Abstract Competitive interactions with non‐native species can have negative impacts on the conservation of native species, resulting in chronic stress and reduced survival. Here, juvenile A tlantic salmon ( S almo salar ) from two allopatric populations ( S ebago and L a H ave) that are being used for reintroduction into L ake O ntario were placed into semi‐natural stream tanks with four non‐native salmonid competitors that are established in O ntario streams: brown trout ( S . trutta ), rainbow trout ( O ncorhynchus mykiss ), C hinook salmon ( O . tshawytscha ) and coho salmon ( O . kisutch ). Brown trout and rainbow trout reduced the survival and fitness‐related traits of A tlantic salmon, whereas C hinook salmon and coho salmon had no impact on these traits. These data support theories on ecological niche overlap and link differences in observed aggression levels with competitive outcomes. Measurements of circulating hormones indicated that the A tlantic salmon were not chronically stressed nor had a change in social status at the 10‐month time point in the semi‐natural stream tanks. Additionally, the S ebago population was better able to coexist with the non‐native salmonids than the L a H ave population. Certain populations of A tlantic salmon may thus be more suitable for some environments of the juvenile stream phase for the reintroduction into L ake O ntario.