Wild Adult Steelhead and Chinook Salmon Abundance and Composition at Lower Granite Dam, Spawn Year 2022

Résumé du livre

This report summarizes the abundance and composition of wild adult summer steelhead Oncorhynchus mykiss and spring-summer Chinook Salmon O. tshawytscha returning to Lower Granite Dam in spawn year (SY) 2022. We used a combination of window counts, night time passage rates, fallback-reascension rates, and biological samples collected using a systematic random sample design from the fish trap at Lower Granite Dam to decompose each species by origin, body size, sex, age, and stock. The time series of abundance and composition was then used to calculate adult-to-adult productivity, expressed as recruits per spawner, and smolt-to-adult return rate for each species.