Early winter foraging success, swimming performance and morphology of juvenile landlocked Atlantic salmon reared under semi-wild and hatchery conditions

• Main Authors: Hatanpää, Aurora, Huuskonen, Hannu, Kekäläinen, Jukka, Kortet, Raine, Hyvärinen, Pekka, Vitelletti, Maria Letizia, Piironen, Jorma
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NRC Research Press (a division of Canadian Science Publishing) 2019
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://hdl.handle.net/1807/99159; http://www.nrcresearchpress.com/doi/abs/10.1139/cjfas-2019-0079

Several Finnish populations of salmonids have been maintained exclusively by stocking hatchery-reared fish for several generations, and it is crucial to know whether domestication has affected fitness-related traits and to assess how the developmental environment influences fish phenotypes. Here, we focused on Lake Saimaa landlocked salmon (Salmo salar m. sebago) and studied the role of the early rearing environment in trait formation by comparing juveniles (fingerlings) from three backgrounds: (i) semi-wild (stocked as alevins), (ii) standard hatchery, and (iii) enriched hatchery conditions We compared juvenile morphology, swimming performance, and capability of feeding on natural prey in early winter. We found no differences between standard and enriched hatchery conditions. Semi-wild fish consumed more prey items, but wet mass of stomach contents did not differ among backgrounds. Swimming endurance was comparable among backgrounds. Semi-wild fish had slenderer body shape and longer fins than hatchery-reared fish. The lack of performance differences between hatchery juveniles and their semi-wild conspecifics is possibly due to reduced phenotypic plasticity caused by extremely low levels of genetic diversity in this population. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.