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.

RESUMEN

En noviembre de 1991, el Servicio Nacional de Pesquerías Marinas de los Estados Unidos de Norteamérica, ingresó al salmón (Oncorhynchus nerka) en el Acta de Especies Amenazadas de los Estados Unidos (AEA) bajo la categoría de amenazado. Los últimos remanentes conocidos del stock del Río Snake, regresaron al Lago Redfish, Valle Sawtooth, en la porción central de Idaho. Dos décadas después de haber ingresado esta especie al acta, se han llevado a cabo varias acciones tendientes a conservar a la población, entre las que se incluye el inicio de un programa de rescate genético. El objetivo del presente trabajo es describir el desarrollo e implementación de actividades de rescate genético basado en cultivos, revisar las estrategias actuales de liberación y posterior retorno de adultos y describir la nueva iniciativa de expandir el programa de producción para abordar de forma más efectiva la recolonización y los objetivos de adaptación local. Adicionalmente, se describe cómo se usarán detonantes poblacionales que permitan una transición entre esfuerzos basados en cultivos y esfuerzos basados en hábitats con el fin de facilitar la recuperación de las poblaciones.

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ACKNOWLEDGMENTS

Dan Baker, Travis Brown, Ken Felty, and Brent Snider (IDFG); Carlin McAuley, Debbie Frost, and Bryon Kluver (NMFS); and Dwayne Banks (ODFG) maintained captive broodstocks, managed fish transportation and fish releases, and generated all fish culture information presented in the article. Mike Peterson and Kurtis Plaster (IDFG) implemented monitoring and evaluation programs and developed analytical products presented in the article. The Shoshone-Bannock Tribes provided habitat monitoring and assessment support. Jeff Heindel and Christine Kozfkay (IDFG) and Desmond Maynard (NMFS) coordinated program efforts and provided substantial input to the article. The authors thank Dan Schill for encouraging the development of the article.

FUNDING

Work was primarily funded by the Bonneville Power Administration and coordinated through the Northwest Power and Conservation Council's Fish and Wildlife Program.

Notes

a NOR is the numerical natural-origin return in the watershed.

b pNOB is the proportion of natural-origin spawners taken into the broodstock.

c pHOS is the proportion of hatchery-origin spawners in the natural habitat.

d HOR is the numerical hatchery-origin return in the watershed.

e PNI = pNOB/(pNOB + pHOS) and is the proportional mean fitness of the integrated population relative to the natural population.