Sexual Dimorphism in the Adipose Fin of Pacific Salmon ( Oncorhynchus )

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Beacham, Terry D., Murray, Clyde B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1983
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Pacific; Pink salmon
• Online Access: http://dx.doi.org/10.1139/f83-231; http://www.nrcresearchpress.com/doi/pdf/10.1139/f83-231

Male adipose fins of Oncorhynchus species were 30–50% larger than those of same-sized females, the actual amount depending on the species. Accuracy of classification of the standards ranged from 87% in chinook salmon (O. tshawytscha) to 98% in pink salmon (O. gorbuscha). Testing the method on new samples usually resulted in an accuracy of at least 90% correct identification of sex for any species. Relative size of the adipose fin should allow for easy and accurate external identification of the sexes of silver-bright Oncorhynchus.