Warm Water Salmon
Floating the Yakima River with a purpose
Researchers pursue pools of cool water to support salmon
The saying "still waters run deep" doesn't apply to the Yakima River. Especially this summer, where still waters run shallow and hot. As flows declined and air temperatures hovered at 100 degrees, water temperatures near Prosser mirrored those on coastal Hawaii.??Warm water is becoming all too common in the summer months. So much so, that we have teams floating the river to document refuges of cooler water -- places where fish can hang out to avoid the heat. These safe havens may prove crucial to fish survival.??Led by folks with the Benton Conservation District, Yakama Nation, and U.S. Geological Survey, the goal is to profile these cooler areas and gain data for the lower 100 miles of the Yakima River. Funded by Ecology, the survey will help us protect these sites and meet environmental enhancement objectives of the Yakima River Basin Integrated Plan.
A record year for water temps?
For 12 days this July (2018), average daily river temperatures at Prosser were above 80 degrees! Historically, the monthly mean temperature for July at Prosser is 69.3 degrees. Over the last four years, the rise in river temperatures is notable. In fact, 20 of the 30 warmest river temperatures recorded since 1990 at Prosser were from the years 2015 to 2018. ??These "thermal blocks" are stalling the migration of sockeye salmon. Recently reintroduced to the river by the Yakama Nation, the sockeye are pausing their migration, waiting at the mouth for conditions to improve. Why? Temperatures above 73-77 degrees are considered lethal to salmon. Survival of late spring smolts is also influenced by rapid water warming, especially in drought years.
