It wasn't just the sockeye salmon that suffered in this record hot summer of 2015. Fish and Game's McCall Hatchery made some changes to accommodate over-heated Chinook salmon.
This video explains some of the events and Idaho Fish and Game's response.
“Because of the water temperatures in the South Fork being in the upper seventies, we were seeing a lot of mortality over there with fish that we were holding as well as fish that were in the river swimming free,’ said Joel Patterson, McCall Hatchery Assistant Manager. “So, those fish were then transported here because of elevated temperatures and low flows.”
Normally, the McCall Hatchery is housing catchable rainbow trout in the summer, but those fish were moved out early to lower elevation lakes and streams to make room for the Chinook salmon. Instead of spawning the fish at the trap, it was done at the McCall Hatchery in late August and early September.