Response of Atlantic salmon Salmo salar to temperature and dissolved oxygen extremes established using animal-borne environmental sensors

• Published in: Scientific reports Vol. 7; no. 1; pp. 4545 - 10
• Main Authors: Stehfest, Kilian M., Carter, Chris G., McAllister, Jaime D., Ross, Jeff D., Semmens, Jayson M.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03-07-2017; Nature Publishing Group; Nature Portfolio
• Subjects: 631/158/2455; 631/158/856; 631/601/18; 9/10; Acclimatization; Animals; Aquaculture; Avoidance behavior; Behavior, Animal; Climate change; Contraction; Dissolved oxygen; Ecosystem; Environment; Environmental conditions; Fish; Habitat utilization; Humanities and Social Sciences; Hypoxia; multidisciplinary; Oxygen - analysis; Salmo salar; Salmon; Salmon - physiology; Science; Science (multidisciplinary); Seasons; Stocking; Temperature; Temperature effects; Water - analysis
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-04806-2

Understanding how aquatic species respond to extremes of DO and temperature is crucial for determining how they will be affected by climate change, which is predicted to increasingly expose them to levels beyond their optima. In this study we used novel animal-borne DO, temperature and depth sensors to determine the effect of extremes of DO and temperature on the vertical habitat use of Atlantic salmon
Salmo salar
in aquaculture cages. Salmon showed a preference for temperatures around 16.5 to 17.5 °C, however, selection of preferred temperatures was trumped by active avoidance of low DO (<35% saturation) at the bottom of the cage. In addition to low DO, salmon also avoided warm surface waters (>20.1 
°
C), which led to a considerable contraction in the available vertical habitat. Despite their avoidance behavior, fish spent a large amount of time in waters with suboptimal DO (<60% saturation). These results show that vertical habitat contraction could likely be a significant consequence of climate change if the reduction in DO outpaces the increase in hypoxia tolerance through local adaptation. They furthermore highlight that site-specific environmental conditions and stock-specific tolerance thresholds may need to be considered when determining stocking densities.