Clackamas River Bull Trout Reintroduction Project FY 2012 Annual Report

Bull trout were last documented in the Clackamas River in 1963. A 2007 feasibility study indicated the Clackamas River could biologically support bull trout and would be a good candidate for a reintroduction effort. Implementation of a reintroduction began in 2011, with the goal of establishing a naturally reproducing population of between 300 – 500 spawning adults by the year 2030. In 2012, we continued efforts to reintroduce bull trout into the Clackamas basin by collecting and transferring 509 juveniles, 43 subadults, and 17 adults from the Metolius Basin. In addition, we conducted monitoring and evaluation of the reintroduction to 1) ensure that the proposed action does not threaten the donor stock population, 2) assess the effectiveness of the reintroduction strategy for re-establishing a self-sustaining bull trout metapopulation, and 3) evaluate the effects of the reintroduction on Endangered Species Act-listed salmonids that currently occupy the Upper Clackamas River Subbasin. To meet these objectives, we used redd count data for the donor population and monitored the behavior and survival of tagged fish in the Clackamas using fixed and mobile radio telemetry and fixed passive integrated transponder tag interrogation. Through the first two years of the project, 1) the donor population has remained healthy (>1200 spawning adults); 2) transferred bull trout have dispersed throughout the Clackamas, all but one subadult and one adult have remained in the Clackamas and its tributaries, and some bull trout have exhibited spawning behavior in the first two years of the reintroduction; and 3) bull trout have generally not occupied areas of the Portland General Electric Clackamas River hydroelectric facility in which anadromous smolts may be vulnerable to predation. Implementation and monitoring of the reintroduction project will be evaluated on an annual basis and the strategy will be adaptively managed.