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Identification of juvenile fall versus spring chinook salmon migrating through the lower Snake River based on body morphology

Transactions of the American Fisheries Society

By:
, , ,
DOI: 10.1577/1548-8659(2000)129<1389:IOJFVS>2.0.CO;2

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Abstract

We tested the use of body morphology to distinguish among subyearling fall-run, subyearling spring-run, and yearling spring-run smolts of chinook salmon Oncorhynchus tshawytscha at two lower Snake River dams during the summer emigration. Based on principal-components analysis, subyearling fall-run chinook salmon had smaller heads and eyes, deeper bodies, and shorter caudal peduncles than yearling spring-run chinook salmon. Subyearling spring-run chinook salmon had characteristics of both subyearling fall-run and yearling spring-run chinook salmon. Subyearling fall-run and yearling spring-run chinook salmon were classified with more than 80% accuracy by means of discriminant analysis. Classification accuracy for subyearling spring-run chinook salmon was only 26%. We conclude that body morphology can be used to accurately identify the age of chinook salmon smolts but not the run. Therefore, genetic analyses are the only means of reliably determining the run composition of summer migrants in the lower Snake River.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Identification of juvenile fall versus spring chinook salmon migrating through the lower Snake River based on body morphology
Series title:
Transactions of the American Fisheries Society
DOI:
10.1577/1548-8659(2000)129<1389:IOJFVS>2.0.CO;2
Volume
129
Issue:
6
Year Published:
2000
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Transactions of the American Fisheries Society
First page:
1389
Last page:
1395
Number of Pages:
7