Temporally stable population-specific differences in run timing of one-sea-winter Atlantic salmon returning to a large river system

Abstract

The understanding of migration patterns can significantly contribute to conservation and management. The spawning migrations of Atlantic salmon (Salmo salar) cover thousands of kilometers from the feeding areas at sea to their natal rivers to reproduce. Migrating salmon are exposed to intensive harvest, but little is known of the population-specific differences in migration behavior. In this study, timing of return migration was investigated among one-sea-winter Atlantic salmon within a river system. By utilizing knowledge of the genetic population structure, population of origin was reliably identified for c. 1500 fish caught in mixed stock fisheries after adopting an approach to minimize the complications arising from potential nonsampled populations. Results demonstrated significant and temporally stable differences among populations as well as between sexes. Generally, female salmon from tributary populations entered fresh water first. Run timing was not however related to in-river migration distance. Rather, one-sea-winter salmon from larger populations and with a higher proportion of multi-sea-winter females arrived later in the season. These findings are a significant step toward a more thorough understanding of the salmon migration behavior and behavioral ecology, providing concrete tools for the management and conservation of the remaining indigenous Atlantic salmon stocks.

Across rather than between river genetic structure in Atlantic salmon Salmo salar in north‐east Scotland, UK: potential causes and management implications

“…The findings outlined here have implications for studies that use genetic stock identification (GSI) to identify the origins of individuals in mixed‐stock situations. Such techniques have been used with S. salar at many geographic scales, including inter‐continental (Reddin & Friedland, ), regional (Gilbey et al, ), river (Griffiths et al, ) and within‐river (Vähä et al, ). In situations where river‐level assignments were attempted, the occurrence of cross‐river structure, as seen here, means that care should be taken where single sites are used in GSI studies to represent an entire river.…”

Genomic signatures of fine‐scale local selection in Atlantic salmon suggest involvement of sexual maturation, energy homeostasis and immune defence‐related genes

“…Thus, there is strong potential for differential selection and local adaptation within the system. Teno salmon subpopulations vary in the timing of their re‐entry to freshwater to spawn (“run timing”; June–August; Vähä et al., ) and the proportion of multi‐seawinter adults among spawners (Vähä, Erkinaro, Niemelä, & Primmer, ). Recently, Aykanat et al.…”

Finding Markers That Make a Difference: DNA Pooling and SNP-Arrays Identify Population Informative Markers for Genetic Stock Identification

“…For example, these methods are used for detecting population specific migration patterns [17], estimating the proportion of farm escapees in salmon fisheries [4], [18] and identification of non-native hatchery-bred individuals in wild populations [19].…”