 | RMECAT-2007-403-00 | Proposal Version 1 | Existing Project | Pending BPA Response | 2007-403-00 | Spring Chinook Captive Propagation-Idaho | Idaho Department of Fish and Game’s (IDFG) long-term management objective for Chinook salmon Oncorhynchus tshawytscha is to maintain Snake River salmon populations at levels that will provide sustainable harvest (IDFG 2007). Restoring currently depressed wild populations to historic levels is a prerequisite to this condition. Until smolt-to-adult survival increases, our challenge is to preserve the existing metapopulation structure (by preventing local or demographic extinctions) of these stocks to ensure they remain extant to benefit from future recovery actions. This project is developing technology that may be used in the recovery of the listed Snake River spring/summer Chinook salmon evolutionarily significant unit (ESU), which consists of 31 subpopulations (i.e. breeding units or stocks); (McClure et al. 2003). Preserving the metapopulation structure of this ESU is consistent with the various Snake River Salmon Recovery Plans (NMFS 1995; Schmitten et al. 1997; McClure et al. 2003), and supports the Northwest Power and Conservation Council’s (NPCC) goal of maintaining biological diversity while doubling salmon and steelhead runs (NPCC 1994).
Idaho and Oregon state, tribal, and federal fish managers met during 1993 and 1994 to discuss captive culture research and implementation in the Snake River basin. The outcome of those meetings was to initiate two programs: 1) the Oregon Department of Fish and Wildlife (ODFW) would initiate a captive broodstock program using selected Grande Ronde River Chinook salmon populations, and 2) the IDFG would initiate captive rearing research using selected Salmon River Chinook salmon populations. Captive fish culture techniques begin by bringing naturally produced juveniles (eggs, parr, or smolts) into captivity and rearing them to sexual maturity in a hatchery. At this point, the two programs use different techniques. The F1 generation in a captive rearing program (IDFG) is returned to their natal streams and allowed to spawn naturally. Alternately, the F1 generation from a captive broodstock program (ODFW) is spawned in the hatchery, where the resulting F2 progeny are held until smoltification. The F2 generation is then released as smolts to its natal stream to emigrate volitionally.
Little scientific information regarding captive culture techniques for Pacific salmonids was available at the inception of these programs, but a substantial amount of new literature was published in the ensuing years. The Chinook Salmon Captive Propagation Technical Oversight Committee (CSCPTOC) was formed to convey this new information between the various state, federal, and tribal entities involved in the captive culture of Chinook salmon. The CSCPTOC meets approximately every two months, which allows an adaptive management approach to all phases of the program and provides a forum of peer review and discussion for all activities and culture protocols associated with this program. Flagg and Mahnken (1995) provided an initial literature review of captive rearing and captive broodstock technology, which provided the knowledge base upon which the program was designed. Using this work, the IDFG captive rearing program for Salmon River Chinook salmon was initiated to further develop this technology by monitoring and evaluating captive-reared fish during rearing and post-release spawning phases. Since the program’s inception, studies documenting the spawning behavior of captive-reared Chinook salmon (Berejikian et al. 2001b), coho salmon O. kisutch (Berejikian et al. 1997), and Atlantic salmon Salmo salar (Fleming et al. 1996) have been published. Other studies have also compared the competitive behavior of male captive-reared and natural coho salmon during spawning (Berejikian et al. 2001a), and the competitive differences between newly emerged fry produced by captive-reared and natural coho salmon (Berejikian et al. 1999). Finally, Hendry et al. (2000) reported on the reproductive development of sockeye salmon O. nerka reared in captivity. Nonetheless, the success of the captive rearing approach to produce adults with the desired morphological, physiological, and behavioral attributes to spawn successfully in the wild had remained somewhat elusive (Fleming and Gross 1992, 1993; Joyce et al. 1993; Flagg and Mahnken 1995).
The IDFG captive rearing program was developed as a way to increase the number of naturally spawning adults and maintain metapopulation structure in selected populations at high risk of extinction while avoiding the impacts of multigenerational hatchery culture described in Reisenbichler and Rubin (1999). The strategy of captive rearing is to prevent cohort collapse in the target populations by returning captive-reared adults to natural spawning areas to augment depressed natural escapement (or replace it in years when no natural escapement occurs). This maintains the continuum of generation-to-generation smolt production and provides the opportunity for population maintenance or increase, should environmental conditions prove favorable for that cohort.
To achieve this goal, the program is testing the efficacy of the captive rearing conservation approach for the conservation of Snake River spring/summer Chinook salmon. Project activities are divided into two parts: 1) develop and implement culture practices and facility modifications necessary to rear Chinook salmon to maturity in captivity having morphological, physiological, and behavioral characteristics similar to natural fish; and 2) evaluate the spawning behavior and success of captive-reared individuals under hatchery and natural conditions. These objectives divide the program into two functional units (fish culture and field evaluations), but the success of the program is dependent on the synchronous development of both.
The IDFG captive rearing program started in 1995 on the Lemhi River (LEM), the East Fork Salmon River (EFSR), and the West Fork Yankee Fork Salmon River (WFYF). That year, brood year (BY) 1994 Chinook salmon parr were collected in these three study streams. Since then, naturally spawned Chinook salmon progeny from BY95-BY05 have been collected and reared in captivity to continue the project. Parr were collected from 1995-1998, and eyed-eggs were collected 1999-2005. Hassemer et al. (1999, 2001), Venditti et al. (2002, 2003a, 2003b, 2005), and Baker et al. (2006, 2008) summarize project activities from inception through 2006. Project activities were completed on the LEM in 2003 with the release of mature BY99 adult fish, enabling increased monitoring intensity on the EFSR and WFYF through present day.
PROJECT METHODS:
1. Hatchery Propagation:
a. Early Rearing (eyed-egg through smolt):
Approximately 300 eyed-eggs were collected from wild/natural redds from each of two study streams, the East Fork Salmon River (EFSR) and the West Fork Yankee Fork Salmon River (WFYF). Eyed-eggs were collected from five to six wild/natural redds per stream and the eggs were transported to Eagle Fish Hatchery (EFH) propagation. EFH cultured these Chinook salmon through the smolt stage at which time they were transported to Manchester Research Station for seawater rearing through maturation. While in culture at EFH; water temperature and growth rates were monitored closely to produce smolts similar in size as to their natural counterparts. During early rearing (first 15 months), juveniles were maintained in family groups based on the redd the eyed-eggs are collected from, at this point juveniles were PIT tagged and groups are mixed, while maintaining segregation between stocks. Before transfer to seawater, the juveniles were vaccinated with Renogen and Vibrogen, and marked with an Elastomer tag.
b. Adult Holding:
Maturing adult Chinook salmon were transported back to EFH for temporary holding on freshwater before release to natal streams (July/August).
2. Spawning Performance Monitoring and Evaluation:
a. Eyed-egg collections:
IDFG research biologists monitored wild/natural Chinook salmon spawning activities, documenting redd development (location) and stream temperatures. Based on this information, eyed-eggs are collected from five to six redds in each drainage (300 eyed-eggs from each drainage) by hydraulically sampling (redd pumping) individual redds collecting 50 to 60 eyed-eggs per redd. These eggs were transported to EFH for rearing (see #1 above).
b. Adult Observations:
After maturing Captive Reared Chinook salmon adults were transported back to EFH, adults were marked for visual identification in the field after release. Petersen Disc, jaw, or floy tags were used to mark individual fish. A blocking weir was installed on the EFSR to contain the captive reared salmon in the observation area (wild/natural salmon and other species were allowed to move up or down stream freely. Radio transmitters were also inserted in eight to ten adults to assist with adult movements within each drainage after release. Spawning observations included: habitat selection (pool, rifle/run, cut bank, overhead vegetation) and behavioral observations (holding, aggression, courting, moving, milling). spawn timing, and spawning behavior.
c. Reproductive Success:
Genetic samples were collected from all released captive-reared adult salmon (1997-2010) and all natural returning adults to the EFSR adult trap facility (2004-2009). In addition, genetic samples will continue to be collected from all natural returning adults to the EFSR adult trap facility (2010-2014). This information will be used to determine if spawning events from captive-reared Chinook salmon produced progeny that successfully outmigrated to the ocean and subsequently returned as adults to the EFSR using parental exclusion genetic analyses. | Eric Stark (Inactive) | | | 06/04/2010 | 11/28/2012 | Eric Stark (Inactive) | Idaho Department of Fish and Game (IDFG), National Oceanic and Atmospheric Administration | Artificial Production | None | RME / AP Category Review | RM&E Cat. Review - RM&E | BiOp |
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