Salmon populations may adapt their eggs to survive in degraded rivers

A University of Southampton study suggests that the membrane of salmon eggs may evolve to cope with reduced oxygen levels in rivers, thereby helping their embryos to incubate successfully.

The research, funded by the Environment Agency and published in the journal Royal Society Open Science, has found that differences in the structure of the thin film surrounding a salmon embryo affects its ability to absorb dissolved oxygen from river water.

Atlantic salmon are in decline in their natural habitats and it’s thought this is partly due to a reduction in the quality of the water in which they spawn. Sediments washed off the land can starve rivers of oxygen by encouraging more organic matter to grow and by silting up the gravel beds where salmon lay their eggs in nests (redds). The eggs rely on a sufficient flow of oxygen across their membranes to successfully incubate and this latest study examines how the structure of these membranes vary in different salmon populations.

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