Putting the Red Back in Redfish Lake, 20 Years of Progress Toward Saving the Pacific Northwest's Most Endangered Salmon Population

Abstract

In November 1991, the U.S. National Marine Fisheries Service listed Snake River Sockeye Salmon (Oncorhynchus nerka) as endangered under the U.S. Endangered Species Act (ESA). The last known remnants of the Snake River stock return to Redfish Lake in the Sawtooth Valley in central Idaho. In the ensuing two decades since the ESA listing, many actions have been taken to conserve the population, including the initiation of a hatchery‐based gene rescue program. The chief aim of this article is to describe the development and implementation of hatchery‐based gene rescue activities, review present‐day release strategies and associated adult returns, and describe a new effort underway to expand program production to more effectively address recolonization and local adaptation objectives. In addition, we describe achievable population triggers to allow the transition from a hatchery‐based effort to a habitat‐based effort that should allow natural population recovery to proceed.

Search for the Smoking Gun: Identifying and Addressing the Causes of Postrelease Morbidity and Mortality of Hatchery‐Reared Snake River Sockeye Salmon Smolts

“…; Kline and Flagg ). Results from release strategy evaluations identified that releasing smolts resulted in higher adult return rates than other reintroduction strategies (Kline and Flagg ). Recognizing this, program managers began pursuing authorization and funding to increase smolt production space to more effectively address population recolonization and rebuilding objectives (Kline et al.…”

“…After securing the genetic legacy of Snake River Sockeye Salmon (Kalinowski et al. ) and increasing the size of the captive broodstock program (Kline and Flagg ), the program shifted toward rebuilding the anadromous life history component of the population. Rearing in captivity circumvents the high mortality rates observed in the natural environment and can quickly result in broodstock replacement and amplification for highly fecund salmonid species (Flagg et al.…”

“…The outcomes of these strategies were then monitored and evaluated (Hebdon et al. ; Kline and Flagg ). Results from release strategy evaluations identified that releasing smolts resulted in higher adult return rates than other reintroduction strategies (Kline and Flagg ).…”

“…Smolt rearing at Springfield Hatchery was phased in over a period of 3 years, with projections to release 250,000 smolts in 2015 and 1 million in 2017. Both captive‐reared and returning anadromous broodfish are artificially spawned annually at Eagle Hatchery and the NMFS hatchery facilities for captive broodstock replacement and smolt production (see Kline and Flagg ). Eyed eggs for smolt production are shipped from these facilities to Springfield Hatchery and reared to the smolt stage of development.…”

The Productivity and Viability of Snake River Sockeye Salmon Hatchery Adults Released into Redfish Lake, Idaho

“…The captive broodstock program was created over an 8‐year period and captured multiple age‐classes, life stages, and life histories in the collection of the founding broodstock including all of the wild, anadromous adults that returned from 1991 to 1998, smolts that emigrated from Redfish Lake from 1991 to 1993, and residual adults collected in Redfish Lake from 1992 to 1995 (Kalinowski et al. ; Kline and Flagg ). The creation of the captive broodstock prevented the imminent extinction of the population.…”