Oncorhynchus nerka population monitoring in the Sawtooth Valley Lakes
Critical habitat for endangered Snake River sockeye salmon includes five rearing lakes located in the Sawtooth Valley of central Idaho. Most of the lakes contain either introduced or endemic kokanee populations. Snake River sockeye occur naturally in Redfish Lake, and are being stocked in Redfish and Pettit Lakes. Because kokanee compete with sockeye for limited food resources, understanding population characteristics of both species such as spawn timing, egg-to-fry survival, distribution and abundance are important components of sockeye recovery. This chapter describes some of those characteristics. In 1995, hydroacoustic estimates of O. nerka densities in the Sawtooth Valley Lakes ranged from 57 to 465 fish/ha. Densities were greatest in Pettit followed by Redfish (167), Alturas (95), and Stanley Lakes. O. nerka numbers increased from 1994 values in Pettit and Alturas Lakes, but declined in Redfish and Stanley. Despite a decline in total lake abundance, O. nerka biomass estimates in Redfish Lake increased. Approximately 144,000 kokanee fry recruited to Redfish Lake from Fishhook Creek. O. nerka fry recruitment to Stanley and Alturas lake was 5,000 and 30,000 fry, respectively. Egg-to-fry survival was 14% in Fishhook and 7% in Stanley Lake Creek. In Fishhook Creek, kokanee spawning escapement was estimated using stream surveys and a weir. Escapement estimates were 4,860 from weir counts, and 7,000 from stream surveys. As part of the kokanee reduction program, 385 of the spawning female kokanee were culled. Escapement for Stanley Lake Creek was only 60 fish, a ten fold decrease from 1994. In Alturas Lake, kokanee spawners dropped by 50% to 1,600.
- Research Organization:
- Shoshone-Bannock Tribal Fisheries Dept., Fort Hall Reservation, ID (United States)
- OSTI ID:
- 405698
- Report Number(s):
- DOE/BP/22548-4; ON: DE96014750; TRN: 97:000650
- Resource Relation:
- Other Information: PBD: May 1996; Related Information: Is Part Of Snake River Sockeye salmon habitat and limnological research. Annual report 1995; Teuscher, D.; Taki, D.; PB: 151 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Snake River Sockeye Salmon Habitat and Limnological Research; 1998 Annual Report.
Snake River Sockeye Salmon Captive Broodstock Program Research Elements : 2007 Annual Project Progess Report.