UBC study establishes formula for predicting climate change impact on sal...( University of British Columbia resea...)

University of British Columbia researchers have found a way to accurately predict the impact of climate change on imperilled Pacific salmon stocks that could result in better management strategies.

The findings, among the first to quantify a relationship between river temperature and salmon mortality rate, are published in the current issue of the journal Physiological and Biochemical Zoology.

While climate change and rising river temperatures have been linked to dwindling salmon stocks, other factors have made it difficult to measure the exact impact these including diseases, fisheries and man-made structures such as dams and fish ladders.

"Calculating the affect of climate change on animal fitness has been particularly challenging for scientists," says lead author Tony Farrell, who is jointly appointed in the Dept. of Zoology and the Faculty of Land and Food Systems.

"Animals have a thermal window, or high and low temperatures between which they are at their best for aerobic activities. Our study has shown that high temperatures push certain sockeye salmon stocks beyond their thermal window, resulting in cardiovascular failure and death," says Farrell.

Led by Farrell and Prof. Scott Hinch in the Dept. of Forest Sciences and the Institute for Resources, Environment and Sustainability, the UBC team has been studying Pacific salmon using biotelemetry trackers for a decade. They have identified the optimal thermal windows for several species of Pacific salmon, which coincide with the historic temperatures the fish would have encountered while migrating in the river.

In 2004, unusually warm river temperatures and earlier entry into the Fraser River system contributed to the "disappearance" of 70 per cent of the Weaver Creek sockeye stock.

"We analyzed river temperature data and the sockeye's migration dates and found that almost half of the population likely experienced temperatures that wou
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