Counts of Gill Rakers and Pyloric Caeca in Pink Salmon

Abstract

Counts of gill rakers and pyloric caeca on pink salmon (Oncorhynchus gorbuscha) from different rivers in British Columbia overlap in range to such an extent that it would be impossible with any degree of accuracy to assign isolated individuals from an ocean population to a distinct "breeding group" on the basis of these characters. While the comparison of the averages of each character demonstrates significant differences between separate rivers in the same year in some cases, in others no such difference is noticeable. The averages for the characters do not consistently show differences between populations of two succeeding years which are known to be distinct, e.g. those of 1940 and 1941.

Meristic and morphometric variation in pink salmon (Oncorhynchus gorbuscha) in southern British Columbia and Puget Sound

“…Stocks within each brood line were more similar to each other with respect to gill-raker frequencies than they were to stocks in the alternate brood line. Pritchard (1945) also surveyed gill-raker frequencies of pink salmon in British Columbia. He found that stocks in the oddyear brood line from the Fraser River had more gill rakers than stocks in the even-year brood line from the Queen Charlotte Islands, but the difference was not significant (G = 10.42, df = 6,0.05 < P < 0.10).…”