Evaluation of the relationship among time of ocean entry, physical and biological characteristics of the estuary and plume environment, and adult return rates, 2002

This study examines the relationship among time of juvenile salmon ocean entry, physical and biological characteristics of the estuary and nearshore ocean plume environment, and smolt-to-adult return rates (SARs) for spring chinook salmon reared by the Clatsop Economic Development Committee Fisheries Project in the lower Columbia River. During 2002, six groups of yearling spring chinook salmon were transferred from Willamette Hatchery to net pens in Blind Slough in the Columbia River estuary, reared for 10 days, and released at 10-day intervals from 10 April through 30 May. Size and smolt development (gill Na+-K+ ATPase activity) at release were similar among groups. Coded-wire tags will be recovered from adults beginning in 2004 from the Blind Slough terminal gill net fishery. Contract no. W66QKZ20374368