Within‐stock variations of life‐history traits in juvenile Atlantic salmon ( Salmo salar )

• Published in: Ecology of Freshwater Fish
• Main Authors: Prévost, E., Chadwick, E. M. P., Claytor, R. R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1993
• Subjects: Ecology; Aquatic Science; Ecology, Evolution, Behavior and Systematics; Atlantic salmon; Newfoundland; Salmo salar
• Online Access: http://dx.doi.org/10.1111/j.1600-0633.1993.tb00086.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-0633.1993.tb00086.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0633.1993.tb00086.x

Abstract Variations in space (geographical location) and time (year) of phenotypic traits linked to life‐history (size, growth, condition and sexual maturation) were analysed within the population of Atlantic salmon ( Salmo salar L.) 1 + parr of Little Codroy River (southwest Newfoundland). The hydrographic system was divided into 10 zones: 4 for the mainstem and 6 for the tributaries. Despite the small size of the river studied, a highly significant spatial heterogeneity was observed. Within the mainstem, size, growth and rate of maturation of males tended to decrease when progressing upstream. When compared with the tributaries as a whole, the mainstem had smaller salmon juveniles, both at the end of the first winter (mainstem: 67.6 mm; tributaries: 73.3 mm) and at 1 + age (mainstem: 80.6 mm; tributaries: 88.3 mm), and the proportion of maturing fish among 1 + males was lower (mainstem: 48.6%; tributaries: 74.2%). According to the feature considered, from 20% to 70% of the spatial effect was due only to differences between the mainstem and the tributaries as a whole. A strong year effect was also revealed. Life‐history traits seemed to fluctuate over time independently from one tributary to another, whereas patterns in their yearly variations were basically consistent among zones in the mainstem. The potential role of genetic and environmental factors in explaining changes in space and time of biological characteristics of parr is discussed. Within a small system such as Little Codroy River, spatio‐temporal life‐history variations of Atlantic salmon juveniles were most likely driven by environment.