by NOAA Fisheries
Section 8.4 Snake River Sockeye Salmon
This Species Summary provides a general overview of the detailed technical analysis relating to Snake River Sockeye. The full statement of NOAA Fisheries Opinions, and the technical analyses on which they are based, is found in the FCRPS Biological Opinion, the Upper Snake Biological Opinion and the Supplemental Comprehensive Analysis, respectively.
The SR sockeye salmon ESU includes all anadromous and residual sockeye from the Snake River basin, Idaho, as well as artificially propagated sockeye salmon from the Redfish Lake Captive Broodstock Program. Although sockeye salmon were historically numerous in many areas of the Snake River basin prior to the European westward expansion, only a single remnant population, residing in Redfish Lake, now remains.
From 1988 through 1999, the number of sockeye observed returning to the sole remaining population at Redfish Lake varied from 0 to 8 fish, with only three years among the 11 in which more than 1 fish returned. Since that time, almost all of the returning fish have been of hatchery origin, and the number of returning fish has been largely a function of the number of hatchery fish released, with returns as high as 257 adult sockeye in 2000, and an average of about 12 fish per year over the past 5 years. In addition, a substantial number of juvenile and adult fish of hatchery origin from this ESU are present in various rearing facilities as part of a captive broodstock program. Although this program appears to be warding off complete extinction of the ESU, there is no longer a self-perpetuating, naturally spawning population of Redfish Lake Sockeye, nor has there been since at least 1988.
In 1990, the Biological Review Team considering the proposed listing of this ESU recognized Snake River Sockeye as "functionally extinct", but left open the possibility that the ESU might be re-established through a conservation hatchery program. Since 1991, there has been an aggressive experimental hatchery program, including the captive broodstock program, to preserve and re-establish this ESU.
The designated critical habitat for SR sockeye salmon includes all Columbia River estuarine areas and river reaches upstream to the confluence of the Columbia and Snake rivers; all Snake River reaches from the confluence of the Columbia River upstream to the confluence of the Salmon River; all Salmon River reaches from the confluence of the Snake River upstream to Alturas Lake Creek; Stanley, Redfish, Yellow Belly, Pettit, and Alturas lakes (including their inlet and outlet creeks); Alturas Lake Creek; and that portion of Valley Creek between Stanley Lake Creek and the Salmon.
Current Status & Recent Trends
The Interior Columbia Basin TRT has stated that this species at very high risk of extinction. Between 1991 and 1998, all 16 of the natural-origin adult sockeye salmon that returned to the weir at Redfish Lake were incorporated into the captive broodstock program. The program has used multiple rearing sites to minimize chances of catastrophic loss of broodstock and has produced several hundred thousand eggs and juveniles, as well as several hundred adults, for release into the wild. Between 1999 and 2007, more than 355 adults returned from the ocean from captive broodstock releases Ð almost 20 times the number of wild fish that returned in the 1990s. The program has been successful in its goals of preserving important lineages of Redfish Lake sockeye salmon for genetic variability and in preventing extinction in the near- term. The Stanley Basin Sockeye Technical Oversight Committee has determined that the next step toward meeting the goal of amplifying the wild population is to increase the number of smolts released.
The most important factor limiting recovery of SR Sockeye is the absence of a self- sustaining, naturally-spawning population. Also limiting is the small number of available broodstock and possible genetic bottlenecks that may be impairing the viability of the ESU. The major factors limiting the conservation value of critical habitat for SR sockeye are the effects on the migration corridor posed by the mainstem lower Snake and Columbia River hydropower system, reduced tributary stream flows and high temperatures, and barriers to tributary migration. The Redfish Lake watershed lies within designated wilderness and the conservation value of the non-wilderness lake area habitat is considered good to excellent. Ocean conditions that have also affected that status of this ESU have been generally poor for this ESU over at least the last four brood cycles, improving only in the last few years.
Current Ocean and Mainstem Harvest
Few sockeye are caught in ocean fisheries. Ocean fishing mortality on Snake River Sockeye is assumed to be zero. Fisheries in the mainstem Columbia River that affect SR sockeye are currently managed subject to the terms of the US v. Oregon Interim Management Agreement for 2005-2007. These fisheries are limited to ensure that the incidental take of ESA-listed SR sockeye does not exceed specified rates. Non-Indian fisheries in the lower Columbia River are limited to a harvest rate of 2%. Treaty Indian fisheries are limited to a harvest rate of 5 to 7% depending on the run size of upriver sockeye stocks. Actual harvest rates have ranged from 0 to 1.8%, and 2.8 to 7.0%, respectively.
Effects of the Prospective Actions on the Snake River Sockeye ESU
The Prospective Actions include two hydrosystem measures that will further support the recovery of SR sockeye salmon: 1) work with appropriate parties to investigate feasibility and potentially develop a plan for ground transport of adult sockeye from Lower Granite Dam to Redfish Lake and 2) assess the feasibility of using increased PIT-tagging for better estimates of juvenile smolt survival from Redfish Lake to Lower Granite Dam and through the mainstem FCRPS projects. In addition, the Action Agencies will provide funding for expanding the numbers of smolts released by the hatchery safety net program, the next step toward meeting the goal of amplifying the wild population. Implementation of estuary habitat projects that remove passage barriers and improve water quality are expected to improve migration conditions in the lower Columbia for juvenile and adult SR sockeye. Improvements to juvenile survival are also expected from actions that reduce piscivorous predation in the mainstem and avian predation in the estuary.
Because this ESU has ceased to function as a self-perpetuating population in the wild, the survival and prospects for recovery of this ESU are primarily dependent upon the hatchery program that sustains them. The Prospective Actions would result in an approximately 10-fold increase in the number of sockeye produced by the captive broodstock program, greatly increasing the number of sockeye released to the wild, and thereby increasing the prospects of restoring a viable wild population. Although these measures are not certain to result in a recovery for this ESU, they address the major factor limiting such recovery in a manner that is consistent with the best available scientific information.
The State of Idaho did not identify any habitat-related actions and programs by non-Federal entities that are expected to benefit SR sockeye salmon
The aggregate effect of the environmental baseline, the Prospective Actions, and cumulative effects will be an improvement in the viability of SR sockeye salmon. Important limiting factors will be addressed by improvements to mainstem hydrosystem passage and estuary habitat and decrease in predation rates. Further, the prospective increase in the number of smolts released from the captive broodstock program is the next logical step toward building a naturally-spawning population. Recognizing the extremely low numbers of adults returning since before this species was listed, this ESU has faced and continues to face substantial obstacles to achieving recovery. In light of the ESU's status and obstacles to recovery, the Prospective Actions take the next steps indicated by the best science available and consistent with the advice of the Stanley Basin Sockeye Technical Oversight Committee to position SR sockeye for eventual improvement toward recovery. In this way the Prospective Actions provide for the SR sockeye's survival with an adequate potential for recovery, taking into account the obstacles faced.
The principal effects of the Prospective Actions will be improvements to mainstem hydrosystem passage, estuary habitat, and predation rates (juvenile migration corridors free of obstructions), and to increase the amount and quality of estuarine habitat (estuarine areas with water quality, natural cover/shelter, and forage that can be used for the transitions between fresh- and saltwater, juvenile growth and development before entering the plume and the final development of adults before they migrate to upstream spawning areas).
The aggregate effect of the environmental baseline, Prospective Actions, and cumulative effects will be an improvement in the functioning of PCEs used for juvenile migration and juvenile and adult transitions between fresh and salt water. Considering the ongoing and future effects of the environmental baseline and cumulative effects, the Prospective Actions will be adequate to ensure that they will not reduce the ability of critical habitat to serve its conservation role for this species.
Critical Habitat Findings
The Prospective Actions to improve habitat in the estuary will affect the PCEs of water quality and safe passage in the migration corridor for juvenile SR sockeye migrants.
After reviewing the effects of the Prospective Actions, including the effects of the environmental baseline, and any cumulative effects, NOAA Fisheries determines (1) that Snake River Sockeye ESU is expected to survive with an adequate potential for recovery and (2) that the affected designated critical habitat is likely to remain functional (or retain the ability to become functional) to serve the intended conservation role for the species in the near and long term. NOAA Fisheries therefore concludes that the Prospective Actions are not likely to jeopardize the continued existence of the Snake River Sockeye ESU nor result in the destruction or adverse modification of its designated critical habitat.
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