Lyons Ferry Hatchery Evaluation: Summer Steelhead and Trout Report 2001 and 2002 Run Years

As part of the Lower Snake River Compensation Plan (LSRCP) mitigation program, Lyons Ferry Complex (LFC) released summer steelhead into area rivers, and rainbow trout were stocked into local lakes during the springs of 2002 and 2003. Additionally, fry and fingerling rainbow trout were reared and provided to Idaho Fish and Game during those same years. Sub-groups of released juvenile steelhead were tagged with a combination of the following internal/external tags/marks (freeze brand, coded-wire tag (CWT), Visual Implant Elastomer (VIE) tag, adipose and ventral fin clip) and released into the Tucannon, Walla Walla, Touchet, Snake, and Grande Ronde rivers. In addition, Passive Integrated Transponder (PIT) tags were used to monitor migration timing and success through the Snake and Columbia River dams, and for determining smolt-to-adult survival in Tucannon River natural and endemic brood smolts captured and released from the Tucannon River smolt trap. Detection and survival rates varied among the groups but were likely related to bypass efficiency at each collector facility. All previous PIT tag releases (1994-2002) were summarized using the SURPH2 survival estimator, and compared to detection rates.

Natural and hatchery origin steelhead smolts were also captured/sampled/PIT tagged at the Tucannon River smolt trap (2001/2002 migration). A population estimate by age class was completed for the naturally produced population.

Residualism of endemic brood hatchery steelhead in the Tucannon and Touchet rivers was monitored through a combination of electrofishing estimates and smolt trapping (Tucannon River only). Endemic stock residualism rates based on these methods indicated relatively low residualism. However, our methods do not allow for an assessment of fish removed from the trout fishery, or from mortality immediately following release until the time of summer electrofishing sampling. The length frequency of residuals that were sampled during electrofishing surveys appeared to be spread uniformly across the release group.

Adult trapping occurred at Lyons Ferry Hatchery and Cottonwood trap for the collection of standard hatchery broodstock (Lyons Ferry and Wallowa stocks). In addition, endemic broodstock programs continue to be investigated on the Touchet and Tucannon rivers. These programs may eventually replace the Lyons Ferry and/or Wallowa stocks in each of the rivers. Efforts to date have only proven somewhat successful with apparent improved stock performance (survival) in the hatchery for both stocks. However, problems in rearing continue to limit program effectiveness. Adult traps have also allowed access to fish for natural stock characterization. We investigated the use of a resistivity counter on the Touchet River in 2003. Results of the counter were positive and we believe future use will provide accurate counts of returning steelhead into the upper Touchet River. Spawning and egg fertilization procedures on the LFH stock were examined in 2003 with higher egg survival documented in the test groups. Results prompted a change in fertilization procedures (not draining the ovarian fluid prior to fertilization) for both endemic programs and the Wallowa stock where success has generally been poor in the past, but were greatly improved using the new procedure.

National Marine Fisheries Service (new name â€�"NOAA Fisheries” â€" 2003) provided freeze-brand data from adult steelhead captured at Lower Granite Dam for the 2001 and 2002 run years. The data provided insight to the potential stray rates of Lyons Ferry stock steelhead into the upper Snake River Basin. Also, freeze-brand data on the Wallowa stock fish released from the Grande Ronde River at Cottonwood AP, were used to estimate adult returns to the project area. The Lower Granite Dam brand data have generally been more reliable than coded-wire tag estimates.

Creel surveys were conducted in the Washington portion of the Snake River, and it’s tributaries, and in the Walla Walla and Touchet rivers in both run years. We surveyed between 6,600 and 10,200 steelhead anglers. Overall catch rates varied slightly between the years. Anglers interviewed, catch rates, and harvest rates were summarized. We conducted cooperative creel surveys on the Lower Grande Ronde River in Washington with Oregon Department of Fish and Wildlife (ODFW). Grande Ronde creel data (total catch, effort hours, etc.) were summarized by ODFW and provided to WDFW for inclusion in this report.

Spawning ground surveys were conducted in the Tucannon River, portions of the Touchet River, and portions of the Asotin Creek basin in 2002 and 2003. High stream flows in both 2002 and 2003 made surveys difficult, and did not allow a final estimate to be calculated. Electrofishing surveys on the Tucannon and Touchet rivers, and Asotin Creek were conducted during July and August each year. The numbers of naturally produced steelhead in LSRCP rivers were similar to previous years and appear to be generally stable. The juvenile estimates in 2002 from most of the sites sampled showed an increase in densities that was likely due to the very strong return in 2001/2002.

Preliminary genetic stock analysis of Tucannon and Touchet river natural origin steelhead, and LFH stock steelhead was completed. Results indicate that each of these natural stocks remain genetically distinct from the LFH stock despite years of supplementation in each basin. Tucannon and LFH stocks are more similar and indicate some introgression between the two. Further analysis of the Tucannon and LFH stocks needs to occur, and long-term monitoring of the genetic characteristics of the new endemic broodstock(s) should occur because of the small founding populations used.

In summary, the Lyons Ferry summer steelhead program continues to meet and/or exceed its original mitigation goals by supplying large returns for harvest within the Lower Snake River area. However, impacts to listed salmonid species and other non-target species may not be within acceptable limits. Further evaluation and monitoring must occur to fully assess these impacts (i.e. reproductive success of hatchery and native fish where they co-exist), and to implement changes in the future. In the interim, production of both LFH and Wallowa stocks were decreased as a precautionary measure. The degree and rate of straying of LFH and Wallowa stocks needs to be summarized for upcoming Subbasin Planning efforts. Genetic stock characterization needs to continue, especially with the new broodstock developments, and additional analysis is needed in the Tucannon River to determine the degree of stock introgression with the LFH stock.