Population differences in response to hypoxic stress in Atlantic salmon
J Côte1, J-M Roussel, S Le Cam
1INRA, UMR 985 Ecologie et Santé des Ecosystèmes, Rennes, France. cote.jessica@wanadoo.fr
Journal of Evolutionary Biology
|October 31, 2012
Summary
Atlantic salmon (Salmo salar) embryos show high adaptability to low oxygen (hypoxia) due to environmental changes. However, distinct population differences suggest varied adaptive potential for future conservation efforts.
Area of Science:
- Evolutionary biology
- Conservation biology
- Aquatic ecology
Background:
- Aquatic organisms face environmental shifts from human activities, impacting river ecosystems.
- Fine sediment in rivers reduces dissolved oxygen, creating hypoxic stress.
- Hypoxic stress is detrimental to Atlantic salmon (Salmo salar) embryos developing in gravel beds.
Purpose of the Study:
- To investigate the adaptive potential of Atlantic salmon populations to hypoxic stress.
- To compare the responses of genetically distinct salmon populations under varying oxygen conditions.
- To assess the heritability and plasticity of early life-history traits under hypoxia.
Main Methods:
- A common garden experiment was employed using four genetically differentiated Atlantic salmon populations.
- Factorial crossing designs measured additive genetic variation in early life-history traits.
- Embryos were reared under normoxic and hypoxic conditions, monitoring survival, incubation time, and length.
Main Results:
- Hypoxic conditions significantly reduced embryo survival and delayed hatching compared to normoxic conditions.
- Distinct hypoxia reaction norms were observed among populations, indicating varied responses.
- Sire × treatment interactions were significant, and heritability tended to decrease under stress.
Conclusions:
- Atlantic salmon populations exhibit significant phenotypic plasticity in response to hypoxia.
- Differences in reaction norms suggest varied adaptive potential among populations.
- Understanding these variations is crucial for effective conservation of salmon in changing riverine environments.
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