Dépôt numérique

Comparing the behavioural thermoregulation response to heat stress by Atlantic salmon parr ( Salmo salar ) in two rivers.

Corey, Emily, Linnansaari, Tommi, Dugdale, Stephen J., Bergeron, Normand ORCID: https://orcid.org/0000-0003-2413-6810, Gendron, Jean‐François, Lapointe, Michel et Cunjak, Richard A. (2020). Comparing the behavioural thermoregulation response to heat stress by Atlantic salmon parr ( Salmo salar ) in two rivers. Ecology of Freshwater Fish , vol. 29 , nº 1. p. 50-62. DOI: 10.1111/eff.12487.

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Climate change is expected to increase the frequency and magnitude of extreme thermal events in rivers. The Little Southwest Miramichi River (LSWM) and the Ouelle River (OR) are two Atlantic salmon (Salmo salar) rivers located in eastern Canada, where in recent years, water temperatures have exceeded known thermal limits (~23°C). Once temperature surpasses this threshold, juvenile salmon exploit thermal heterogeneity to behaviourally thermoregulate, forming aggregations in coolwater refuges. This study aimed to determine whether the behavioural thermoregulation response is universal across rivers, arising from common thermal cues. We detailed the temperature and discharge patterns of two geographically distinct rivers from 2010 to 2012 and compared these with aggregation onset temperature. PIT telemetry and snorkelling were used to confirm the presence of aggregations. Mean daily maximum temperature in 2010 was significantly greater in the OR versus the LSWM (p = 0.005), but not in other years (p = 0.090–0.353). Aggregations occurred on 14 and 9 occasions in the OR and LSWM respectively. Temperature at onset of aggregation was significantly greater in the OR (Tonset = 28.3°C) than in the LSWM (Tonset = 27.3°C; p = 0.049). Logistic regression models varied by river and were able to predict the probability of aggregation based on the preceding number of hours >23°C (R2 = 0.61 & 0.65; P50 = 27.4°C & 28.9°C; in the OR and LSWM respectively). These results imply the preceding local thermal regime may influence behaviour and indicate a degree of phenotypic plasticity, illustrating a need for localised management strategies.

Type de document: Article
Mots-clés libres: Atlantic salmon; behavioural thermoregulation; heat stress; movement; thermal refuge; water temperature
Centre: Centre Eau Terre Environnement
Date de dépôt: 08 mars 2021 19:46
Dernière modification: 14 févr. 2022 20:09
URI: https://espace.inrs.ca/id/eprint/11424

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