Clackamas River Bull Trout Reintroduction Project FY 2014 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 the bull trout reintroduction program

began in 2011, with the goal of establishing a naturally reproducing population of between 300 –

500 spawning adults by the year 2030. In 2014, we continued efforts to reintroduce bull trout

into the Clackamas basin by collecting and transferring 305 juveniles, 46 subadults, and 7 adults

from the Metolius Basin. Monitoring and evaluation were conducted 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 population, 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 obtained 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 four years of the project, 1) the donor population has remained

healthy (>900 spawning adults); 2) transferred bull trout have dispersed throughout the upper

Clackamas, all but one subadult and one adult have remained in the Clackamas and its

tributaries, and some bull trout have exhibited spawning behavior; and 3) bull trout have

generally not occupied areas of the Portland General Electric Clackamas River hydroelectric

project 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

reintroduction strategy will be adaptively managed.