Tucannon River Spring Chinook Salmon Hatchery Evaluation Program: 2001 Annual Report

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Published: September 2002

Publication number: FPA 02-10

Author(s): Michael P. Gallinat, Lance Ross and Michelle Varney

Abstract

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 2001 to April 2002.

Six hundred eighty-one fish were captured in the TFH trap in 2001 (404 natural adults, 1 natural jack, 181 hatchery adults, and 95 hatchery jacks); 106 were collected and hauled to LFH for broodstock and the remaining fish were passed upstream.

During 2001, all fish collected for broodstock were spawned. Prespawning mortality has been low since broodstock began being held at LFH in 1992, and is generally less than 10% each year.

Spawning in 2001 at LFH occurred between August 28 and September 18, with peak eggtake on September 11. A total of 184,127 eggs were collected. Egg mortality to eye-up was 2,225 eggs, with an additional loss of 6,698 sac-fry. Total fry ponded for production in the rearing ponds was 174,934. One hundred twenty-five mature 1997 brood year females from the captive broodstock program were spawned in 2001. Mean fecundity was 1,990 eggs/female based on 105 fully spawned females; egg survival was 69%. Forty-one mature 1998 brood year females were also spawned in 2001. Mean fecundity based on 39 fully spawned females was 1,160 eggs/female; egg survival was 81%.

One wild male spring chinook salmon that was radio tagged at Bonneville Dam entered the Tucannon River in 2001. This fish had also been PIT tagged as a juvenile at the Tucannon River smolt trap. Growth rate from capture at the smolt trap to radio tagging at Bonneville Dam averaged 27.3 mm/month.

WDFW staff conducted spawning ground surveys in the Tucannon River between August 29 and October 3, 2001. One hundred sixty-eight redds and 112 carcasses were found above the adult trap and 130 redds and 114 carcasses were found below the trap in 2001 Based on annual redd counts, broodstock collection, and in-river pre-spawning mortalities, the estimated escapement for 2001 was 1,012 fish (892 adults and 120 jacks).

Length and weight samples were collected twice during the rearing cycle for 2000 BY juveniles at TFH and Curl Lake Acclimation Pond. All 2000 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 2001 to determine the population of subyearling and yearling spring chinook in the Tucannon River. We estimated 44,618 subyearlings (BY 2000) and 397 yearlings (BY 1999) were present in the river. Evaluation staff also operated a downstream migrant trap. During the 2000/2001 emigration, we estimated that 8,157 (BY 1999) 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 continue to average about five times higher than for hatchery salmon. However, hatchery salmon survive about five times greater than natural salmon from parent to adult progeny. Natural fish survival remains below the replacement level, while hatchery fish survival is nearly three times above it. Due to the low SAR for hatchery fish, the mitigation goal of 1,152 salmon of Tucannon River stock was not achieved.