University of Oulu

Marttila, M., Louhi, P., Huusko, A. et al. Rev Fish Biol Fisheries (2019) 29: 513.

Synthesis of habitat restoration impacts on young-of-the-year salmonids in boreal rivers

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Author: Marttila, Maare1,2,3; Louhi, Pauliina1,2; Huusko, Ari4;
Organizations: 1Natural Resources, Natural Resources Institute Finland (Luke), Oulu, Finland
2Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
3Lapland Centre for Economic Development, Transport and Environment, Rovaniemi, Finland
4Natural Resources, Natural Resources Institute Finland (Luke), Paltamo, Finland
5Natural Resources, Natural Resources Institute Finland (Luke), Helsinki, Finland
6Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
7Freshwater Centre, Finnish Environment Institute (SYKE), Helsinki, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.4 MB)
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Language: English
Published: Springer Nature, 2019
Publish Date: 2019-09-05


River restoration offers the potential to enhance biological integrity, often measured as fish population changes. We used a meta-analytical approach to synthesize density responses to in-stream habitat restoration by young-of-the year (YOY) brown trout and Atlantic salmon in 28 rivers (overall 32 restoration projects) in Finland. We also examined which local and watershed-scale factors most influenced restoration success. Finally, we conducted an expert survey to obtain an independent estimate of a sufficient density enhancement for restoration to be considered successful. Despite strong context-dependency, habitat restoration had an overall positive effect on YOY salmonid density. When compared to target levels derived from the expert survey, density responses mainly reached the minimum expected success rate, but remained short of the level considered to reflect distinct success. Variability in restoration responses of trout was linked mainly to river size, predominant geology, water quality and potential interspecific competition (trout vs. European bullhead). Fishing mortality tended to obscure positive effects of restoration and stocking by YOY fish affected negatively trout’s response to restoration, supporting a shift towards self-sustainable schemes in fisheries management. These results imply that habitat restoration is a useful approach for improving the ecological and conservational status of salmonid populations in boreal rivers. To further improve the success rate, and thereby public acceptance, of restorations they need to be complemented by other management measures that enhance the potential for the recovery of threatened salmonid populations.

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Series: Reviews in fish biology and fisheries
ISSN: 0960-3166
ISSN-E: 1573-5184
ISSN-L: 0960-3166
Volume: 29
Issue: 3
Pages: 513 - 527
DOI: 10.1007/s11160-019-09557-z
Type of Publication: A2 Review article in a scientific journal
Field of Science: 1181 Ecology, evolutionary biology
Funding: Open access funding provided by Natural Resources Institute Finland (LUKE). This study was supported by the Maj and Tor Nessling Foundation, Maa- ja vesitekniikan tuki ry and Academy of Finland (AKVA grant no. 263597).
Academy of Finland Grant Number: 263597
Detailed Information: 263597 (Academy of Finland Funding decision)
Dataset Reference: Supplementary material:
Copyright information: © The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.