Northwest Fisheries Science Center

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Document Type: Contract Report
Center: NWFSC
Document ID: 6373
Title: Effects of water-borne pollutants on salmon passage at John Day Dam, Columbia River (1982-1984)
Author/Editor: David M. Damkaer, Douglas B. Dey
Publication Year: 1985
Publisher: National Marine Fisheries Service
Contracting Agency: U.S. Army Corps of Engineers, Portland, Oregon
Pages: 85
Date: 1985

Migrating adult salmonids have been found to delay for an inordinate time before passing John Day Dam on the Columbia River.  Fishways and flows at John Day are not substantially different from those at other large dams, particularly at Bonneville and The Dalles Dam, where apparently there are no such passage delays.  Recent cooperative studies between the National Marine Fisheries Service and U.S. Army Corps of Engineers have suggested that these migratory delays may be related to or caused by industrial pollutants in the forebay of the John Day Dam.

In 1982, it was determined, from studies of the distributions of a large number of pollutants, that the reported fish-passage delays might be caused in part by fluorides, free heavy metals (cadmium, copper, lead, and zinc), and/or aromatic hydrocarbons.  Each of these pollutants, especially the first and third categories, appeared to be related to activities at the primary aluminum-production plant located on the north shore of the reservoir just upstream from John Day Dam.  Because of the apparent relationship of fluoride concentrations around John Day Dam to the reported discharges of fluoride from the aluminum plant, and because of the relative intractability of experimentation with heavy metals and hydrocarbons, it was decided to focus research on the effects of fluoride on the migratory behavior of adult salmon.

The rationale, approach, and methods for the field studies in the John Day Dam region are outlined the first of three reports.  Studies on the effects of low levels of fluoride on the behavior of returning salmon were added in the second year of the investigation and reported in 1984.  Both the field and behavioral components were continued in this third and final year of investigation of adult salmon delay at John Day Dam.