Idaho Fish and Game trapped two sockeye at fish traps in the Sawtooth Basin near Stanley on July 28, which are the first fish for 2022 and part of what could be the largest sockeye return in years. Through July 28, there were 2,041 sockeye counted at Lower Granite Dam about 30 miles downstream from Lewiston, which is nearly three times the 10-year average and the third-highest on record since counting began at Lower Granite in 1975.
To reach the Sawtooth Basin, sockeye must swim 900 miles from the ocean and 6,250 vertical feet. Historically, about 50 to 60 percent of the sockeye that cross Lower Granite reach the Sawtooth Basin. The fish still have about 450 miles remaining to complete their journey, which can be hampered by a variety of factors, including low water in the Snake and Salmon rivers and warm temperatures that can slow their progress and make their final migration to the Sawtooth Basin more difficult.
The first sockeye are earlier than last year by about a week. However, warm water last year that was potentially lethal prompted biologists to trap sockeye at Lower Granite Dam and truck them to the Eagle Hatchery to ensure some returning fish were available for spawning. Idaho’s total return last year was 240 sockeye, but only 55 made the entire migration to the Sawtooth Basin on their own.
Sockeye returns to the Sawtooth Basin have fluctuated wildly over the last decade from a low of 17 in 2019 to a high of 1,579 in 2014.
When Idaho sockeye were listed in 1991 under the federal Endangered Species Act, only four adult sockeye returned to the Sawtooth Basin. The total number of sockeye that returned between 1991-99 was 23 fish, including two years when no sockeye returned.
To save Idaho’s sockeye salmon run, Fish and Game biologists in the 1990s initiated a captive broodstock program with 16 adult sockeye – 11 males and five females – that returned to Idaho between 1991 to 1998. Through advanced aquaculture techniques, the program has retained about 95 percent of the species’ genetic variability and gradually increased the annual returns to Idaho.