Mature male parr contribution to the effective size of an anadromous <scp>A</scp>tlantic salmon ( <scp>S</scp>almo salar ) population over 30 years

• Published in: Molecular Ecology
• Main Authors: Johnstone, Devon L., O'Connell, Michael F., Palstra, Friso P., Ruzzante, Daniel E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2013
• Subjects: Genetics; Ecology, Evolution, Behavior and Systematics; Almo; Newfoundland
• Online Access: http://dx.doi.org/10.1111/mec.12186; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmec.12186; https://onlinelibrary.wiley.com/doi/pdf/10.1111/mec.12186

Abstract We describe temporal changes in the genetic composition of a small anadromous A tlantic salmon ( S almo salar ) population from South Newfoundland, an area where salmon populations are considered threatened ( COSEWIC 2010). We examined the genetic variability (13 microsatellite loci) in 869 out‐migrating smolt and post‐spawning kelt samples, collected from 1985 to 2011 for a total of 22 annual collections and a 30 year span of assigned cohorts. We estimated the annual effective number of breeders ( N b ) and the generational effective population size ( N e ) through genetic methods and demographically using the adult sex ratio. Comparisons between genetic and demographic estimates show that the adult spawners inadequately explain the observed N e estimates, suggesting that mature male parr are significantly increasing N b and N e over the study period. Spawning as parr appears to be a viable and important strategy in the near absence of adult males.