Interspecific association of brown trout (Salmo trutta) with non-native brook trout (Salvelinus fontinalis) at the fry stage

Lovén Wallerius, M., Näslund, J., Koeck, B. and Johnsson, J. I. (2017) Interspecific association of brown trout (Salmo trutta) with non-native brook trout (Salvelinus fontinalis) at the fry stage. Ethology, 123(12), pp. 933-941. (doi: 10.1111/eth.12692)

149890.pdf - Accepted Version



The introduction of non-native brook trout (Salvelinus fontinalis) in Europe has led to displacement and decreasing populations of native brown trout (Salmo trutta). Some studies have found that brown trout shift to a diet niche similar to brook trout when the two species live in sympatry, which conflicts with the competitive exclusion principle. A change in feeding niche may be a sign of early interspecific association and social learning, leading to behavioral changes. As a first step to address this possibility, it is essential to assess the interspecific association between the species during the early ontogenetic life stages. In this study, we therefore assess whether juvenile brown trout associate with non-native juvenile brook trout to the same extent as with conspecifics by setting up two experiments: (i) a binomial choice test allowing visual and chemical cues to estimate the species specificity of group preference, and (ii) an association test without physical barriers to estimate the degree of association of a focal brown trout with a group of either conspecifics or heterospecifics. In experiment (1), we found that focal juvenile brown trout preferred to associate with the stimuli groups and did not discriminate either against conspecific or heterospecific groups. Furthermore, more active individuals showed stronger preference for the stimuli group than less active ones, regardless of species. In experiment (2), we found that brook trout groups had a tighter group structure than brown trout groups, and that focal brown trout showed stronger association with brook trout than with brown trout. These results indicate that brown trout may associate with brook trout at an early life stage, which would allow for interspecific social learning to occur. Future studies should look closer into causes and consequences of interspecific association and social learning, including potential effects on the phenotype selection in brown trout populations.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Koeck, Dr Barbara
Authors: Lovén Wallerius, M., Näslund, J., Koeck, B., and Johnsson, J. I.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Ethology
ISSN (Online):1439-0310
Published Online:11 October 2017
Copyright Holders:Copyright © 2017 Blackwell Verlag GmbH
First Published:First published in Ethology 123(12): 933-941
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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