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Identification of Hatchery and Naturally Spawning Stocks of Columbia Basin Spring Chinook Salmon by Scale Pattern Analyses
Author(s) -
Schwartzberg Matthew,
Fryer Jeffrey K.
Publication year - 1993
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1993)013<0263:iohans>2.3.co;2
Subject(s) - chinook wind , oncorhynchus , hatchery , fishery , stock (firearms) , spring (device) , environmental science , geography , biology , fish <actinopterygii> , mechanical engineering , archaeology , engineering
Scale pattern analysis (SPA) was used to differentiate hatchery and natural‐origin stocks of spring‐run chinook salmon Oncorhynchus tshawytscha of age 1.2 (= age 4; spent one winter as juveniles in fresh water and two winters in the ocean; one winter of egg incubation is implied) from the Snake, Wenatchee, and Deschutes subbasins of the Columbia River basin. Linear discriminant analyses indicated that hatchery and natural‐origin stocks within each subbasin could be identified with a relatively high degree of accuracy. High classification accuracies were also obtained by comparing pooled hatchery stocks from the three Columbia River subbasins with pooled natural‐origin stocks from those same subbasins. For a composite mixed‐stock analysis, samples of unknown origin were obtained from Bonneville Dam, a site on the lower Columbia River where a mixed population of spring chinook salmon stocks is found. This analysis, which was done with a classification model based on pooled hatchery and natural‐origin stocks, estimated that 71% (90% confidence intervals of 61–81%) of age‐1.2 spring chinook salmon sampled at Bonneville Dam were of hatchery origin. The classification model used in the mixed‐stock analysis was derived from a limited set of representative samples of known stocks. Estimating hatchery and natural‐stock composition of mixed‐stock populations by using SPA and a limited set of representative known‐stock samples is a potentially valuable technique for management of Columbia basin spring chinook salmon. This technique may also prove applicable to management of other mixed‐stock Pacific salmon populations.