Natural production monitoring and evaluation, annual report 2000

This report covers efforts to monitor age composition of wild adult spring/summer chinook salmon returning to the Snake River Basin. Accurately determining the ocean age proportions of wild adult spring/summer chinook salmon is important information for monitoring the status and trends of these species. During this report period, project personnel selected the preferred structure for aging, set up a database to track all samples collected, developed procedures and ordered equipment for structure preparation and reading, and aged the adults that were sampled in 1999. Chinook salmon carcasses were sampled from representative spawning areas throughout the Snake River Basin. Ocean age proportions were determined for each 5 centimeter fork length group for wild adult spring/summer chinook salmon returning to the Snake River. These ocean age proportions were applied to the number and estimated length frequency distribution of wild chinook salmon adults passing Lower Granite Dam to estimate the number of adult returns for each ocean age group