Spring Chinook Salmon Oncorhynchus tshawytscha Supplementation in the Clearwater Subbasin ; Nez Perce Tribal Hatchery Monitoring and Evaluation Project, 2007 Annual Report.

Abstract

The Nez Perce Tribal Hatchery (NPTH) program has the following goals (BPA, et al., 1997): (1) Protect, mitigate, and enhance Clearwater Subbasin anadromous fish resources; (2) Develop, reintroduce, and increase natural spawning populations of salmon within the Clearwater Subbasin; (3) Provide long-term harvest opportunities for Tribal and non-Tribal anglers within Nez Perce Treaty lands within four generations (20 years) following project initiation; (4) Sustain long-term fitness and genetic integrity of targeted fish populations; (5) Keep ecological and genetic impacts to non-target populations within acceptable limits; and (6) Promote Nez Perce Tribal management of Nez Perce Tribal Hatchery Facilities and production areas within Nez Perce Treaty lands. The NPTH program was designed to rear and release 1.4 million fall and 625,000 spring Chinook salmon. Construction of the central incubation and rearing facility NPTH and spring Chinook salmon acclimation facilities were completed in 2003 and the first full term NPTH releases occurred in 2004 (Brood Year 03). Monitoring and evaluation plans (Steward, 1996; Hesse and Cramer, 2000) were established to determine whether the Nez Perce Tribal Hatchery program is achieving its stated goals. The monitoring and evaluation action plan identifies the need for annual data collection and annual reporting. In addition, recurring more » 5-year program reviews will evaluate emerging trends and aid in the determination of the effectiveness of the NPTH program with recommendations to improve the program's implementation. This report covers the Migratory Year (MY) 2007 period of the NPTH Monitoring & Evaluation (M&E) program. There are three NPTH spring Chinook salmon treatment streams: Lolo Creek, Newsome Creek, and Meadow Creek. In 2007, Lolo Creek received 140,284 Brood Year (BY) 2006 acclimated pre-smolts at an average weight of 34.9 grams per fish, Newsome Creek received 77,317 BY 2006 acclimated pre-smolts at an average of 24.9 grams per fish, and Meadow Creek received 53,425 BY 2006 direct stream release parr at an average of 4.7 grams per fish. Natural and hatchery origin spring Chinook salmon pre-smolt emigrants were monitored from September - November 2006 and smolts from March-June 2007. Data on adult returns were collected from May-September. A suite of performance measures were calculated including total adult and spawner escapement, juvenile production, and survival probabilities. These measures were used to evaluate the effectiveness of supplementation and provide information on the capacity of the natural environment to assimilate and support supplemented salmon populations. « less