The first sockeye of 2021 has naturally returned to the Stanley Basin on Aug. 7 after dangerously warm water in the Snake and Salmon rivers in July prompted Idaho Fish and Game biologists to trap and transfer fish from Lower Granite Dam to Eagle Fish Hatchery. Biologists safely transported 201 sockeye from Lower Granite to ensure the fish will be available for spawning.
Rivers have cooled and migration condition improved, and a second sockeye followed on Aug. 10, but it could still be a tough year for salmon making the full migration to the Sawtooth Basin. The first fish typically returns to the area around the third week of July and sockeye continue returning into late September and early October.
“While this is good news that a sockeye has made the full migration to the Sawtooth Valley basin, we still expect the percentage of fish able to make that trip this year will be well below the average conversion rate of approximately 51 percent," John Powell, Fish and Game Principal Fisheries Research Biologist. "This reduced migratory survival is why we decided to trap fish at Lower Granite Dam and haul them to Eagle Fish Hatchery, where those fish and natural returners will be safely held until it’s time to spawn in the fall.”
Rivers continue to run lower and warmer than usual, so biologists remain concerned that the sockeye return at Lower Granite – 617 fish through Aug. 7 – would likely return to Stanley at lower rates than in the past.
The Lower Granite return so far is below the 10-year average of 800 sockeye, and slightly below last year’s total of 640 at Lower Granite. Of those, 151 sockeye returned to the Sawtooth Basin last year..
Sockeye returns to the Sawtooth Basin have fluctuated wildly over the last decade from a low 17 in 2019 to a high of 1,579 in 2014 and a 10-year average of 437.