Idaho's first sockeye of the year arrived in late July, and what was once doubtful is now tradition

On July 23, the first sockeye salmon of the year swam into a fish trap in the Sawtooth Basin near Stanley. Over the last decade, the first sockeye’s arrival has become predictable in late July or early August, but what’s now routine was doubtful nearly 35 years ago when the remnants of Idaho’s sockeye were swimming toward extinction. 

Over a thousand sockeye this summer have migrated past Lower Granite Dam, which is about 40 miles downstream from Lewiston, and about midway through their migration. These fish are heading toward the Sawtooth Basin, which is a huge increase from 1991 when Idaho sockeye were listed under the federal Endangered Species Act. Only four adult sockeye returned to the Sawtooth Basin that year, and only 23 fish total returned between 1991 and 1999, which included two years when none returned.

Over the last decade (2015-’24), the annual Idaho sockeye return has averaged 221, which ranged from a low of 17 to a high of 774.

An epic migration loaded with pitfalls

To reach the Sawtooth Basin, sockeye must swim 900 miles upstream from the Pacific Ocean and climb 6,250 vertical feet. Historically, about 50 to 60 percent of the sockeye that cross Lower Granite Dam eventually reach their destination.

After crossing Lower Granite, the fish have about 450 miles remaining on their journey. Their trek can be hampered by a variety of factors, including low water in the Snake and Salmon rivers. Warm temperatures from summer heat can slow their progress, deplete their energy and make their final migration to the Sawtooth Basin extremely difficult. 

This summer, hot weather and potentially lethal hot water prompted biologists to truck 164 sockeye from Lower Granite Dam directly to the Eagle Hatchery to ensure spawners are available to produce the next generation. That may be a recurring strategy as summers become hotter and rivers are warmer during sockeye migrations.  

Rebuilding from the remnants

To save Idaho’s sockeye salmon run in the 1990s, Fish and Game biologists initiated a captive broodstock program with 16 adult anadromous sockeye – 11 males and five females, 886 out-migrating smolts, and 26 residual adults. These fish were collected between 1991 to 1998, and through genetic testing and carefully controlled breeding, the broodstock program retained about 95 percent of the species’ genetic variability. 

Now a mix of hatchery and naturally reared sockeye return each year, and the captive broodstock program raises and retains some adult sockeye in hatcheries as a safeguard in case none return from the ocean. The captive broodstock have also helped biologists increase the number of young fish available to migrate to the ocean, and also increased the number of adult fish returning. 

Sockeye returns are still modest compared with Idaho’s other salmon, and their future is not guaranteed. But Fish and Game’s sockeye program has pulled them back from the brink of extinction, and through careful management, kept redfish returning to their namesake lake in the Sawtooth Basin.