Evaluation of Atlantic salmon parr responses to habitat improvement structures in an experimental channel in Newfoundland, Canada
✍ Scribed by Mitchell, J. ;McKinley, R. S. ;Power, G. ;Scruton, D. A.
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 217 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0886-9375
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✦ Synopsis
Distributional patterns and microhabitat selection of Atlantic salmon (Salmo salar) parr were investigated in relation to habitat improvement structures in a controlled flow experiment channel at Noel Paul's Brook, Newfoundland. The channel consisted of six replicates, each containing three randomly arranged treatments. Each replicate included a control treatment with no habitat modification, a mid-channel treatment with a boulder cluster and low-head barrier dam, and a stream bank treatment with undercut banks and wing deflectors. The influence of size class, density, discharge and diurnal/nocturnal differences on microhabitat selection were evaluated. Results showed that the mid-channel treatment did not serve its purpose at lower discharges (0.032 -0.063 m 3 s -1 ), and as a result was not the treatment of choice. However, as the discharge increased (0.13 m 3 s -1 ), more salmon took up residence in this treatment. In all experiments, greater depths were selected in the stream bank treatment, and salmon parr in the mid-channel treatment consistently selected positions closer to cover. Larger parr preferred greater depths and were found closer to the improvement structures. Benthic and drifting food availability were also estimated, and results showed that 'funnelling effects' of the drift were created near the structures. This study indicates that these structures have the potential to create favourable feeding sites, and provide the necessary physical characteristics required by salmon parr.