A subtopic of sexual determination is the sex ratio. As time progresses, this ratio may be skewed, depending on the different lifestyles of the salmon. The process, where the ratio between males and females change, lacks genetic control, and thus can not be altered by genetic means. The ratio between males and females are similar in wild stock populations, as well as in hatcheries. Although the ratio tends to remain stable, there are slight differences between gender in terms of sexual characteristics.
Female fish tend to live longer lives than male fish.
This results in an increased population of female fish in stocks that are spawning. This is one factor that hatcheries must take into consideration. In the male fish, however, growth stops when secondary sexual characteristics appear and when aggression and territoriality develop. The result of the onset of these secondary characteristics is a loss of condition, poor overall appearance, and unsatisfactory flesh texture and taste. Just as sexual traits tend to bring slight differences among gender, crossbreeding allows for differences in offspring.