Fraser River Sockeye Population - Largest Run Left - "Near Upper Limit" Of Survivable Water Temps

[hatrack]

Sockeye salmon in the Fraser River are facing such critically warm water in the summer that populations will either have to adapt or die as climate change pushes temperatures even higher, according to new research at the University of British Columbia.

With oceans, lakes and rivers warming worldwide, the study holds a warning that fish stocks are facing increasingly dire environmental challenges.

To test the thermal tolerance limits of salmon, researcher Erika Eliason placed them on “fish treadmills” in the lab, where temperatures and simulated currents could be adjusted. What Ms. Eliason found was that sockeye, which migrate up to 1,200 kilometers in the Fraser, are already “near their upper limit” for warm water and any further increases could lead to the disappearance of some populations.

The PhD candidate in UBC’s Department of Zoology looked at eight distinct populations of sockeye salmon, and found each group had evolved to deal with local conditions. There are more than 100 sockeye populations in the Fraser and over time they have evolved in response to the specific environmental conditions they face during migration.

EDIT

http://www.theglobeandmail.com/news/national/british-columbia/sockeye-salmon-at-risk-of-overheating-due-to-climate-change-study/article1965320/