Variation in Male Parr Maturation Within and Among Populations of Atlantic Salmon, Salmo salar

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Myers, Ransom A., Hutchings, Jeffrey A., Gibson, R. John
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1986
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1139/f86-154; http://www.nrcresearchpress.com/doi/pdf/10.1139/f86-154

The covariation of growth and maturation in male Atlantic salmon parr, Salmo salar, produces a relationship characterized by a size threshold below which individuals generally do not mature. The threshold of 70–72 mm fork length is evident both within and among populations. Parr maturation can reduce growth during the second year of life by an average of 4.0%. Among-year variation in growth rate affects the yearly incidence of maturation for males at age 1 + but has no detectable effect on the total proportion of male parr maturing in a population. Increases in the proportion of mature parr in the Matamek River, Quebec, can be explained by variation in growth alone; there is no evidence for genetic changes in this population.