A. Abstract

The YKFP is a joint project of the Yakama Nation (lead entity) and the Washington State Department of Fish and Wildlife and is sponsored in large part by the Bonneville Power Administration with oversight and guidance from the Northwest Power and Conservation Council (NPCC). The YKFP experimental design for the supplementation research and Coho reintroduction feasibility projects was developed in 1996.  We propose to continue to test whether new artificial production techniques, coupled with strategic habitat actions, can be used to increase harvest and natural production of Yakima Basin spring Chinook while maintaining the long-term genetic fitness of the population being supplemented and keeping adverse genetic and ecological interactions with non-target species or stocks within acceptable limits. We propose to evaluate the domesticating effects of supplementation, and compare the intensity of domestication incurred under supplementation as practiced in the YKFP spring chinook program to a wild control line and to that incurred under a more conventional regime of continuous hatchery culture.   The experimental designs are adjusted periodically based on the results of the M&E activities. The project is also designed to provide knowledge about supplementation so that it may be used to mitigate effects on anadromous fisheries throughout the Columbia River Basin.

B. Technical and/or scientific background

Before the ocean and lower Columbia exploitation of salmon and steelhead in the late 19th century and early 20th century, and before the Yakima River valley was developed, the Yakima Subbasin supported large runs of spring, summer and fall Chinook, summer steelhead, coho and sockeye.  Historic spring Chinook returns to the Yakima were likely in the range of 202,500 (Mullan 1983) to approximately 250,000 fish (Smoker 1956).  Cumulative effects from the disruption of the Yakima Subbasin ecosystem functions and processes, out of subbasin impacts, and harvest of salmon have resulted in a significant decline of fish and wildlife abundance from historic levels.  Presently, adult salmon and steelhead returns to the Yakima River are approximately two orders of magnitude lower than estimated historic returns.   Over the last ten years, Yakima river mouth returns of spring Chinook have varied from a low of 650 to a high of 23,300.   The significant decrease in abundance of these fish is mirrored on the terrestrial landscape.  Though abundance data is limited for the terrestrial focal species, many important wildlife habitats have been significantly constricted and degraded (YSFWPB 2004a), thus limiting the population potential of wildlife that depend on these habitats.  At the most general levels, the main habitat factors in focal species’ decline within this subbasin are the loss of key habitat quantity, quality, and diversity (YSFWPB 2004a).

Meaningful restoration of salmon and steelhead runs in the Columbia Basin ultimately requires a return to “normative” conditions throughout the basin (Williams et al., 1996), or at least to a much more normative state.  Because of the enormous societal obstacles and economic costs that constrain it, such an effort will take decades to implement and additional decades to take effect. Therefore, mitigation measures such as supplementation will likely be required for the foreseeable future to meet federal treaty trust and other obligations embodied in the FWP (BPA 1996).  Ultimately, the YKFP will comprise a series of complimentary habitat restoration and supplementation/reintroduction projects targeting all species historically present in the subbasin.

Supplementation is a cornerstone of efforts to rebuild salmon and steelhead runs throughout the Columbia Basin (RASP 1991; NPPC 1994; CRITFC 1995).  In the Yakima Subbasin, supplementation seems particularly promising because it has been shown theoretically (Busack and Knudsen, unpublished data) that populations of low productivity (viz., subjected to high* levels of density-independent mortality) are optimal candidates for supplementation, as are populations subject to high levels of predation (Peterman 1987; McIntyre et al., 1988).  Such conditions characterize salmon and steelhead populations in the Yakima Subbasin (Dunnigan and Lamebull 2000; McMichael et al. 1998; Fast et al. 1991, Anonymous 1990). There are, however, concerns that supplementation might fail because of the following factors: poor smolt-adult survival (Miller et al. 1990; Steward and Bjornn 1990), poor reproductive success (Chilcote et al. 1986; Fleming and Gross 1992; Blouin 2003), adverse genetic change (Busack and Currens 1995; Reisenbichler 1997; Waples et al. 1990; Hindar et al. 1991; Waples 1991; Hard 2000; Utter 2004; Goodman 2005), adverse ecological impacts on target and nontarget species (Shoals and Hillock 1979; Collis et al. 1995; Shively et al. 1996; Hillman and Mullan 1989; Peery and Bjornn 1996; Nickelson et al. 1986; Hillman 1989; Reeves et al. 1987; Mullan et al. 1992; Swain and Riddell 1990; Tabor et al. 1993; Ward et al. 1995; Wood 1987) and diminished primary and secondary productivity attributable to the removal of salmon carcasses from streams (Johnston and Ringler 1979; Michael 1995; Bilby et al. 1996; Levy 1997).

A monitoring plan addressing the preceding considerations has been developed for upper Yakima spring Chinook (Busack et al. 1997) including an update focusing on domestication effects (Busack et al. 2004).  The YKFP monitoring program is built on a foundation laid in a number of earlier projects.  The general elements of a monitoring plan were first outlined in the YKFP’s 1993 Project Status Report (BPA 1993).  Other efforts that have contributed to the evolution of the monitoring program include: the Yakima Spring Chinook Enhancement Study (Fast et al. 1991); genetic stock identification and genetic risk issues (Busack 1990; Busack et al. 1991; Busack and Currens 1995; Currens and Busack 1995; Kapuscinski and Miller 1993); power analysis for CESRF control/treatment comparisons (Hoffmann et al. 1994); semi-natural rearing treatment development (Maynard 1995); baseline and post supplementation hatchery/wild interaction studies (Pearsons et al. 1993, 1994, 1996, 1998, 1999, 2001a, 2001b, 2002, 2003, 2004, 2005); Chandler smolt trap passage studies (Neeley 1992; Sandford and Ruehle 1996; Neeley 2001); reproductive success (Berejikian et al. 1997; Schroder et al. 2003, 2004, 2005); spring chinook natural production objectives/strategies (Watson 1993); Yakima flow/survival studies (Yakama Nation, unpublished data); and project-specific marking methods (Schroder and Knudsen 1996).

C. Rationale and significance to regional programs

Research, monitoring and evaluation activities are necessary to develop information to make decisions regarding salmon and steelhead stock protection and restoration objectives in the Yakima Basin.  The YKFP is using adaptive management to guide Project decisions.  Adaptive management requires the development and analysis of information regarding performance of strategies and methods.  
Supplementation is being pursued as a key strategy for stock enhancement and restoration throughout the Columbia Basin.  As defined by RASP (1991), supplementation is “the use of artificial propagation in an attempt to maintain or increase natural production while maintaining long-term fitness of the target population and keeping ecological and genetic impacts to non-target species within specified limits”.  The Independent Scientific Review Panel (ISRP 2005-15) stated, “The critical uncertainties are whether supplementation provides a demographic increase in natural production (the potential benefit) and whether supplementation leads to decreased natural-spawning fitness (the potential harm) in the integrated population.  Supplementation entails demographic, genetic (fitness), ecological, and disease risks.”  This Project is designed to evaluate these uncertainties and risks.  The results of the monitoring and evaluation activities in the Yakima subbasin will be useful for evaluation, design, development and implementation of supplementation programs elsewhere in the Columbia Basin.  However, as noted in the Yakima Subbasin Management Supplement (YSFWPB 2004b, p. 36), the use of supplementation will not, by itself, create a sustainable, naturally-producing population of salmonids in a watershed where the indigenous wild population has been diminished or extirpated.  Habitat quality is the sole determinant of natural population productivity and sustainability.  If supplementation ceases without changing the underlying habitat conditions that required its use in the first place, the remaining, unsupplemented, naturally-producing population will be expected to resume the decline that was apparent before the application of supplementation.  Only adequate habitat quality can ensure the long-term viability of unsupplemented, naturally-producing populations.  The related YKFP Management, Data, and Habitat proposal (198812025) includes objectives and strategies for addressing habitat projects.

With respect to the significance of the Project to regional programs, the research, monitoring and evaluation activities are important to achievement of the fisheries mitigation requirements that are required by the Northwest Power Act (NPA) and implemented through the FWP and subbasin plan.  The fisheries mitigation requirements have framed the historical monitoring and evaluation activities in the Yakima Basin. The proposed activities are also aligned with current NPCC efforts to increase the regional effectiveness of research, monitoring and evaluation activities.