Issue 19: Comments on Snake River Sockeye
by NOAA Fisheries
FCRPS Biological Opinion, May 5, 2008
The Save Our Wild Salmon Coalition comment that the sockeye captive broodstock program should be phased out over time due to lack of fitness.
A number of parties, including NOAA Fisheries have expressed concerns that, because Snake River sockeye reached such low numbers before intervention, genetic bottlenecks will impede recovery. However, recent unpublished data from geneticists for the Stanley Basin Sockeye Technical Oversight Committee indicates that the captive broodstock has similar levels of haplotype diversity as other sockeye populations in the Pacific Northwest (see SCA Section 126.96.36.199). The program reduces the risk of domestication by its spread-the-risk strategy, outplanting prespawning adults and fertilized, eyed eggs as well as juveniles raised in the hatchery. The progeny of adults that spawn in the lakes and juveniles that hatch successfully from the eyed eggs are likely to have adapted to the lake environment.
The Save Our Wild Salmon Coalition and American Rivers comments that the captive broodstock program will only succeed if factors for decline, specifically the FCRPS, are addressed.
NOAA Fisheries agrees that without substantive improvements in smolt-to-adult survival, even the expanded smolt release program is unlikely to rebuild the ESU to self-sustaining levels. Factors limiting the survival of Snake River sockeye include survival through the mainstem Salmon River as well as the hydrosystem. As described in Section 188.8.131.52 (Habitat) of the SCA, large portions of the migration corridor in the Salmon River are water quality limited for temperature, which is likely to reduced the survival of adult sockeye returning to the Stanley Basin in late July and August. Researchers have observed a high loss of adults in the migratory corridor between Lower Granite Dam and the Stanley Basin. The RPA (Hatchery Strategy 2, Action 42) therefore requires the Action Agencies to work with appropriate parties to investigate the feasibility and potentially develop a plan for ground transport of adult sockeye from Lower Granite Dam to the Stanley Basin.
With respect to changes in the FCRPS, at this time there is little route-specific information on the mortality of juvenile Snake River sockeye except that they appear to be relatively susceptible to descaling. The RPA (RME Strategy 2, Action 52) therefore requires that the Action Agencies assess the feasibility of PIT-tagging juvenile Snake River sockeye for specific survival tracking from the Stanley Basin to Lower Granite Dam and through the FCRPS. The expanded smolt release program is expected to increase the potential number of subjects for this type of study. In the meantime, NOAA Fisheries expects the survival of juvenile sockeye to improve with the implementation of surface passage routes at Little Goose, Lower Monumental, McNary, and John Day dams in concert with training spill to provide safe egress (i.e., reduce delay and vulnerability to predators) (see Section 184.108.40.206 of the SCA).
The Colville Tribe's comment that NOAA Fisheries should initiate a satellite broodstock program at a hatchery below Bonneville Dam.
The Stanley Basin Technical Oversight Committee (SBTOC) has in the past discussed the idea of establishing a satellite population in the lower Columbia River. They have rejected this idea primarily because of concern that a large-scale offsite effort would disrupt the evolutionary adaptations required for the 900+ mile migration up the Columbia, Snake, and Salmon Rivers to the Stanley Basin.
The Shoshone-Bannock Tribe's comment that the RPA should require a combination of eyed-egg, adult releases for volitional spawning, and fry and parr releases into lake rearing habitat in concert with increased smolt releases.
NOAA Fisheries has revised RPA Hatchery Strategy 2, Action 41, adding the text underlined below: "Continue to fund the safety net program to achieve the interim goal of annual releases of 150,000 smolts while also continuing to implement other release strategies in nursery lakes such as fry and parr releases, eyed-egg incubation boxes, and adult releases for volitional spawning." RPA Action 42 requires the further expansion of the program to 500,000 to 1 million fish, but the project will continue to implement the "other release strategies."
The Save Our Wild Salmon Coalition comment that the loss of marine-derived nutrients from anadromous salmon carcasses is a key factor limiting the productivity of Sawtooth Valley lakes (citing Selbie et al. 2007).
Based on a study of sediment cores from Redfish Lake, Selbie et al. (2007) concluded that "salmon-derived nutrients [SDN] never contributed substantially to the nutrient dynamics and primary production of Redfish Lake." Although the supply of SDN declined precipitously beginning in the mid-1800s, the authors found evidence that the lake was becoming nutrient enriched in the late 20th Century, "a trend contrary to that expected, given declining salmon escapement and a further reduction in SDN influxes." Whether or not the reduction in SDN is a key factor limiting the recovery of Snake River sockeye salmon, there is evidence that recent nutrient supplementation efforts have successfully increased the productivity of these naturally oligotrophic systems.
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