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The Importance of Including Water Temperature Simulations in a 2D Fish Habitat Model for the St. Lawrence River

Ouellet, Valerie; St-Hilaire, André; Secretan, Yves; Mingelbier, Marc; Morin, Jean; Dugdale, Stephen

The Importance of Including Water Temperature Simulations in a 2D Fish Habitat Model for the St. Lawrence River Thumbnail


Valerie Ouellet

André St-Hilaire

Yves Secretan

Marc Mingelbier

Jean Morin


Extreme climatic conditions likely caused a massive fish mortality during the summer of 2001 in the St. Lawrence River. To corroborate this hypothesis, we used a physical habitat simulation approach incorporating hydraulic and water temperature models. Spawning Habitat Suitability Indices (HSI) for common carp (Cyprinus carpio) were developed using fuzzy logic and applied to the model outputs to estimate habitat weighted usable area during the event. The results revealed that areas suitable for common carp spawning (HSI > 0.3) were severely reduced by high water temperatures, which exceeded 28 °C during the mortality event. During the mortality event, the amount of suitable habitat was reduced to ≤200 ha/day, representing less than 15% of the maximum potential suitable habitat in the study reach. In addition, the availability of cooler habitats that could have been used as thermal refuges was also reduced. These results indicate that the high water temperature in spawning areas and reduced accessibility to thermal refuge habitats exposed the carp to substantial physiological and environmental stress. The high water temperatures were highly detrimental to the fish and eventually led to the observed mortalities. This study demonstrates the importance of including water temperature in habitat suitability models.

Journal Article Type Article
Acceptance Date Jun 21, 2021
Online Publication Date Jun 23, 2021
Publication Date Jul 1, 2021
Deposit Date Jul 13, 2021
Publicly Available Date Jul 13, 2021
Journal Water
Electronic ISSN 2073-4441
Publisher MDPI AG
Peer Reviewed Peer Reviewed
Volume 13
Issue 13
Article Number 1736
Keywords 2D model; common carp; fish habitat; fuzzy logic; water temperature
Public URL
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