The Effect of Temperature During Development on the Number of Scales in the Kamloops Trout, Salmo Kamloops Jordan

An experiment on the Kamloops trout of Kootenay lake was undertaken to determine if temperature conditions prevailing during development might modify the number of scales. Both adult and fingerling trout were found to have an average of 145 rows. Fingerlings reared from parents spawned at the end of the run and therefore exposed to a higher temperature, had an average of 135 rows and were significantly different from their own parents and the population as a whole. In a control set up 5 °C. higher than the normal hatchery temperature, the average value of the brood studied was further reduced by 5 rows. It is suggested that the scale count is probably the reflection of the environmental conditions pertaining during development.