Upper Columbia Spring Chinook Salmon, Steelhead, and Bull Trout Recovery

3.5Hatcheries

Artificial production programs in the Upper Columbia Basin may have affected abundance, productivity, and diversity of naturally produced stocks in several different ways. The NRC (1996) and Flagg et al. (2001) discussed at length the risks and problems associated with use of hatcheries to compensate for, or supplement, fish produced in the wild. NRC (1996) noted demographic risk, pointing out that large-scale releases of hatchery fish exacerbate mixed-stock harvest problems, thereby reducing the abundance of naturally produced fish. Naturally produced fish cannot sustain harvest rates that would be appropriate for hatchery fish.

Measures used in the GCFMP and steelhead management in the Upper Columbia Basin (until recently) quite likely led to some of the listed risks and contributed to decreased genetic diversity of naturally produced fish. For example, steelhead adults were collected at Priest Rapids, and later at Wells Dam, their progeny reared in hatcheries and released as smolts to the various tributaries without regard to fostering local adaptation in tributaries. As another example, the similarity of DNA (deoxyribonucleic acid) collected from natural Entiat River spring Chinook and Entiat NFH samples indicates that Entiat NFH spring Chinook spawn successfully and have introgressed into or may have replaced the natural Entiat River population (Ford et al. 2004).

However, in the Ford et al. (2004) genetic study, the sample size was small and it only covered a limited number of years when spawning escapement of non-local origin hatchery fish was very high. Therefore, it is possible that the Entiat spring Chinook population could have less risk if genetic samples were evaluated over a longer time period with larger sample sizes.

An effect of hatcheries that is little studied, but one that may have affected the abundance and productivity of populations in the Upper Columbia Basin, is the assumed lower reproductive success of hatchery fish that spawn in the wild. That is, hatchery-reared fish that spawn in the wild often have a lower breeding success than naturally produced spawners. For example, Berejikian and Ford (2004) found that the relative reproductive success of hatchery-produced steelhead in an Oregon stream was as low as 2-13%.

Foraging, social behavior, time of spawning, and predator avoidance can differ for fish reared in the hatchery and in the wild (Flagg et al. 2001). While resulting differences may primarily reduce survival of hatchery-produced salmon and steelhead, negative effects may carry into a naturally produced population where adults of hatchery origin spawn with naturally produced fish. Effects of disease on released hatchery fish and on naturally produced fish are poorly understood, but likely to be negative (Flagg et al. 2001).

Hatchery programs may also have ecological effects that reduce the abundance and productivity of populations in the Upper Columbia Basin. NRC (1996) noted that 5.5 billion salmon smolts of all species are released to the wild each year around the Pacific Rim, with potential trophic effects that may lead to altered body size and survival of naturally produced fish. Emphasis on hatchery fish may also deny marine nutrients to infertile rearing streams used by relatively few naturally produced spring Chinook salmon and steelhead. Recent efforts, however, include the outplanting of hatchery carcasses in streams within the Upper Columbia Basin.

Because the Leavenworth and Entiat National Fish Hatcheries continue to release out-of-basin stocks of spring Chinook into their respective subbasins, these programs may be a threat to the diversity of locally derived spring Chinook in those systems. Tagging studies indicate that fish from the Leavenworth National Fish Hatchery generally have low stray rates (<1%) (Pastor 2004).⁵⁵ However, based on expanded carcass recoveries from spawning ground surveys (2001-2004), the Leavenworth National Fish Hatchery and other out-of-basin strays have comprised from 3-27% of the spawner composition upstream from Tumwater Canyon (WDFW, unpublished data). This stray information has contributed to the high risk categorization of the Wenatchee population. Nonetheless, four years of data is not sufficient to evaluate the true spawner composition or its potential effects on the natural Wenatchee spring Chinook population.

Although state-operated artificial production programs emphasize use of locally derived stock for supplementation, they may also affect diversity and productivity of naturally produced stocks. For example, the supplementation programs may affect the age-at-return of spring Chinook, resulting in more younger-aged hatchery fish spawning in the wild (NMFS 2004). This could affect reproductive potential and ultimately productivity of naturally produced fish. The reproductive success of hatchery fish produced in supplementation programs that spawn naturally in the wild needs study. Additionally, straying of hatchery fish within and among populations can increase a population’s risk for genetic diversity. For example, risk increased because Wenatchee River steelhead strayed upstream of Rocky Reach Dam and Chiwawa River Hatchery spring Chinook comprised greater than 10% of the spawner composition in Nason Creek and the White and Little Wenatchee rivers in 2001 and 2002 (Tonseth 2003, 2004).

Hatchery programs for steelhead occur in the Wenatchee, Methow, and Okanogan basins and are operated by WDFW, USFWS, and the Colville Tribes. These programs mitigate for habitat inundated by and juveniles killed at hydroelectric projects. Prior to 1997, most of the hatchery steelhead were of a co-mingled stock collected either at Priest Rapids or Wells dams. In 1997 WDFW began a program of Wenatchee steelhead with broodstock collected from the Wenatchee basin. The Methow and Okanogan basins continue to use broodstock collected at Wells Dam. The combined broodstock for the Methow and Okanogan basins and the high proportion of hatchery fish on the spawning grounds contributes to the high risk of the DPS.

Although there are currently no bull trout artificial propagation programs in the Upper Columbia Basin, the USFWS has determined that reaching a recovery condition in the Upper Columbia Basin within 25 years may require the use of artificial propagation. This may involve the transfer of bull trout into unoccupied habitat within the historic range. Artificial propagation may also involve the use of federal or state hatcheries to assist in recovery. Research is needed to evaluate the effectiveness and feasibility of using artificial propagation in bull trout recovery.