Current and predicted ecological impacts of climate change to Atlantic salmon freshwater productivity in the North Atlantic.
The impacts of diel thermal variability on growth, development and performance of wild Atlantic salmon (Salmo salar) from two thermally distinct rivers.
The study examined how daily temperature fluctuations affect wild Atlantic salmon from two Canadian rivers, Miramichi and Restigouche.
They raised the fish from the parr stage to smolt stage under two different temperature cycles: 16–21°C and 19–24°C.
Both groups of parr grew similarly, but as smolts, those exposed to 19–24°C temperatures experienced slower growth rates, with some fish losing body mass. These smolts also showed higher tolerance to heat (CTmax).
The results indicate that where the fish are from and their life stage affect how they respond to these temperature changes.
This suggests that local adaptation plays a role and highlights how daily temperature cycles can differently impact young Atlantic salmon's growth and survival in their natural habitats.