B.C.’s recent heat wave has led to high water temperatures in the Fraser River. An article in today’s Vancouver Sun notes that early mortality in salmon is linked to water temperatures, although it’s too early to know the full effects on this year’s run. Despite early predictions for an increased sockeye run, sockeye are returning at much lower levels.
The [Department of Fisheries and Oceans] notes that in the past, sockeye have exhibited decreased swimming ability at 18 C, early signs of physiological stress and slow migration at 19, pre-spawn mortality and disease at 20, and severe stress and early mortality at 21 degrees. … [read full article]