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Scientific Report

Age and Length Composition of Columbia Basin Chinook, Sockeye, and Coho Salmon at Bonneville Dam in 2000

Abstract

Five-year-old fish (BY 1995) were estimated to comprise 2% of the spring chinook, 26% of the summer chinook, and 40% of the fall chinook salmon population. Three-year-old fish (BY 1997) were estimated to comprise 14% of the spring chinook, 42% of the summer chinook, and 17% of the fall chinook salmon population. The sockeye salmon population sampled at Bonneville was predominantly four-year-old fish (95%), and the coho salmon population was 99.9% three-year-old fish (Age 1.1). Length analysis of the 2000 returns indicated that chinook salmon with a stream-type life history are larger (mean length) than the chinook salmon with an ocean-type life history. Age classes 0.3 and 0.4 have no significant change over time and age 0.1 chinook salmon had a significant decrease in mean length over time. Based on three-year- old returns, the relationship predicts four-year-old returns of 325,000 (+ 111,600, 90% Predictive Interval [PI]) spring chinook and 27,800 (+ 29,750, 90% PI) summer chinook salmon. Based on four-year-old returns, the relationship predicts five-year-old returns of 54,300 (+ 40,600, 90% PI) spring chinook and 11,000 (+ 3,250, 90% PI) summer chinook salmon.

Authors

Citation

Kelsey, D., and J.K. Fryer. 2001. Age and Length Composition of Columbia Basin Chinook, Sockeye, and Coho Salmon at Bonneville Dam in 2000. Columbia River Inter-Tribal Fish Commission Report reference #01-01, Portland, Oregon.

Date

Feb 9th, 2001

Report No.

01-01

Media Type

CRITFC Technical Report

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