Populations of Fraser River sockeye salmon are so fine-tuned to their environment that any further environmental changes caused by climate change could lead to the disappearance of some populations, while others may be less affected, says a new study by University of British Columbia scientists.
The Fraser River is the longest river in British Columbia, flowing more than 2,000 kilometres through the province. It is known for its large salmon runs, where typically several million sockeye salmon return to the river to spawn each year. There are more than 100 distinct populations of sockeye salmon in the Fraser River watershed and to spawn, each population completes a unique migration route that varies in distance, elevation gain, river temperature and river flow.
For their study, published today as the cover article in the journal Science, UBC researchers studied eight populations of adult Fraser River sockeye and found that populations with the most difficult migrations were more athletic, displaying superior swimming ability and specialized heart adaptations. They also found that the optimal water temperature for a population, or temperature where the fish performed the best, matched the historical river temperatures encountered by each population on its migration routes.
"This is the first large-scale study on wild fish to show how different populations of the same species have adapted to such specific migration conditions," says Erika Eliason, a PhD candidate in the Department of Zoology at UBC and lead author of the study. "As climate change alters the conditions of the Fraser River watershed, our concern is that some populations may not be able to adapt to these changes quickly enough to survive."
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Eliason, who worked on this study with co-authors Tony Farrell, a professor in the Department of Zoology at UBC, and Scott Hinch, a p
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University of British Columbia