Jn. Goldstein et al., Movements of adult Chinook salmon during spawning migration in a metals-contaminated system, Coeur d'Alene River, Idaho, T AM FISH S, 128(1), 1999, pp. 121-129
Spawning migration of adult male chinook salmon Oncorhynchus tshawytscha wa
s monitored by radio telemetry to determine their response to the presence
of metals contamination in the South Fork of the Coeur d'Alene River, Idaho
. The North Fork of the Coeur d'Alene River is relatively free of metals co
ntamination and was used as a control. In all, 45 chinook salmon were trans
ported from their natal stream, Wolf Lodge Creek, tagged with radio transmi
tters, and released in the Coeur d'Alene River 2 km downstream of the confl
uence of the South Fork and the North Fork of the Coeur d'Alene River. Fixe
d telemetry receivers were used to monitor the upstream movement of the tag
ged chinook salmon through the confluence area for 3 weeks after release. D
uring this period, general water quality and metals concentrations were mon
itored in the study area. Of the 23 chinook salmon observed to move upstrea
m from the release site and through the confluence area, the majority (16 f
ish, 70%) moved up the North Fork, and only 7 fish (30%) moved up the South
Fork, where greater metals concentrations were observed. Our results agree
with laboratory findings and suggest that natural fish populations will vo
id tributaries with high metals contamination.