Habitat selection by juvenile Atlantic salmon: the interaction between physical habitat and abundance
Abstract:The effect of physical river habitat variables on the distribution of juvenile Atlantic salmon Salmo salar L. in the Rivière de la Trinité, Québec, Canada, was examined using generalized additive modelling. A survey of Atlantic salmon fry and parr densities and habitat variables (flow velocity, water column depth and substratum size) was conducted in the summer months from 1984 to 1992. Clear patterns of habitat use existed: specific ranges of habitat variables were selected, with parr preferring greater velocities, depths and substratum sizes than fry. There was a large variation, however, in juvenile densities for given velocities, depths or substratum sizes, with this variation being greatest in optimal habitats. On examination of an individual year, interaction between the variables was found to explain some of the variation. On a year‐to‐year basis the juvenile Atlantic salmon population was found to exhibit an ‘Ideal Free Distribution’, which resulted in greatest variation in optimal habitats with year‐to‐year changes in population abundance.
Document Type: Regular Paper
Affiliations: 1: Département de Biologie, Université Laval, Québec, Québec, G1K 7P4, Canada, 2: Institut National de la Recherche Scientifique – Eau, Terre et Environnement (INRS-ETE), 880, chemin Sainte-Foy, Québec, Québec, G1V 4C7, Canada and 3: Direction de la Recherche sur la Faune, Ministère des Ressources Naturelles de la Faune et des Parcs, 675, boul. René-Lévesque Est, boîte 92, Québec, Québec, G1R 5V7, Canada
Publication date: October 1, 2005