Growth data (Snake River sockeye salmon captive propagation)

In the early 1990s, Redfish Lake sockeye salmon from the Sawtooth Basin in Idaho were on the brink of extinction, and they were listed as endangered under the US Endangered Species Act in 1991. To prevent extinction, a gene rescue captive broodstock program was established for the stock that consisted of taking most of the remaining gene pool into captive culture at specialized conservation hatcheries at the Manchester Research Station and the Idaho Department of Fish and Game Eagle Hatchery.

Efforts through the decade of the 1990s consisted of developing techniques for successful culture of sockeye salmon to adulthood, establishing rearing and spawning protocols to ensure preservation of stock diversity, and habitat enhancement at the rearing lakes. In the early 2000s, the program began to include a demographic focus to boost the population through rearing and release of enough juveniles to produce some adult returns. For the last few years, program production has resulted in over 150,000 smolts outmigrating from these rearing lakes annually, with plans for increases to a half million or more. In 2011, and for the fourth year in a row, record numbers of sockeye adults have returned to their native home in Idaho. The fork length to the nearest mm and weight to the nearest gram of a subsample of fish is recorded on an approximately quarterly basis.