Tucannon River Spring Chinook Salmon Hatchery Evaluation Program: 2002 Annual Report

Lyons Ferry Hatchery (LFH) and Tucannon Fish Hatchery (TFH) were built/modified under the Lower Snake River Fish and Wildlife Compensation Plan. One objective was to compensate for the estimated annual loss of 1,152-spring chinook (Tucannon River stock) caused by hydroelectric projects on the Snake River. The standard supplementation production goal is 132,000 fish for release as yearlings at 30 g/fish or 15 fish per pound (fpp). The captive brood production goal is 150,000 yearlings at 30 g/fish. This report summarizes activities of the Washington Department of Fish and Wildlife Lower Snake River Hatchery Evaluation Program for Tucannon River spring chinook for the period April 2002 to April 2003.

Seven hundred seventy-eight fish were captured in the TFH trap in 2002 (166 natural adults, 2 natural jacks, 589 hatchery adults, and 21 hatchery jacks); 107 were collected and hauled to LFH for broodstock and the remaining fish were passed upstream.

During 2002, two salmon that were collected for broodstock died. Prespawning mortality has been low since broodstock began being held at LFH in 1992, and is generally less than 10% each year.

Spawning of supplementation fish in 2002 at LFH occurred between August 27 and September 17, with peak eggtake on September 3. A total of 169,364 eggs were collected from 22 wild and 25 hatchery-origin fish. Egg mortality to eye-up was 3.6% (6,047 eggs), with an additional loss of 11,786 (7.2%) sac-fry. Total fry ponded for production in the rearing ponds was 151,531.

A total of 121 captive brood females were spawned from August 27 to October 2, 2002 producing 176,544 eggs. Egg mortality to eye-up was 68% leaving 55,711 live eggs. An additional 5,249 dead eggs/fry (9.4%) were picked at ponding leaving 50,462 fish for rearing.

One spring chinook salmon that was radio tagged at Bonneville Dam entered the Tucannon River in 2002. This fish entered the adult trap on June 12 and was passed upstream by hatchery personnel. Efforts to locate this fish after it was passed upstream were unsuccessful. The radio tag either quit working or the fish/transmitter left the area.

On August 20, 97 excess captive broodstock were released at Panjab Bridge. All released fish were Monel jaw tagged and radio transmitters were inserted into ten of the largest fish. Only two of the radio tagged females spawned and released captive brood were observed being dominated by hatchery and wild fish in the river.

WDFW staff conducted spawning ground surveys in the Tucannon River between August 22 and October 7, 2002. One hundred ninety-seven redds and 140 carcasses were found above the adult trap and 102 redds and 60 carcasses were found below the trap. Based on redd counts, broodstock collection, and in-river pre-spawning mortalities, the estimated escapement for 2002 was 1,005 fish (341 wild adults, 9 wild jacks and 644 hatchery-origin adults, 11 hatchery jacks).

Length and weight samples were collected three times during the rearing cycle for 2001 BY juveniles at TFH and Curl Lake Acclimation Pond. All 2001 BY juveniles were marked in October at LFH, transported to TFH, and transported again in February to Curl Lake for acclimation and volitional release during March and April.

Snorkel surveys were conducted during the summer of 2002 to determine the population of subyearling and yearling spring chinook in the Tucannon River. We estimated 63,412 subyearlings (BY 2001) and 703 yearlings (BY 2000) were present in the river. Evaluation staff also operated a downstream migrant trap. During the 2001/2002 emigration, we estimated that 20,049 (BY 2000) wild spring chinook smolts emigrated from the Tucannon River.

Monitoring survival rate differences between natural and hatchery-reared salmon continues. Smolt-to-adult return rates (SAR) for natural salmon consistently average about three times higher than for hatchery salmon. However, hatchery salmon survive about four times greater than natural salmon from parent to adult progeny. Due to the low SAR for hatchery fish, the mitigation goal of 1,152 salmon of Tucannon River stock was not achieved.