Allozyme heterozygosity, date of first feeding and life history strategy in Atlantic salmon
Abstract:The relations between allozyme heterozygosity, relative date of first feeding and life history strategy in juvenile Atlantic salmon Salmo salar were examined using eggs obtained from a 400 family cross (20 male × 20 female adult Atlantic salmon). Multilocus heterozygosity, through its positive associations with the timing of first feeding and growth rate, was correlated with life history strategy in juvenile Atlantic salmon, albeit under genotype × environmental (temperature, food availability) regulation. Under hatchery conditions, a 10 day difference was observed in the relative date of first feeding between early and late first feeding Atlantic salmon. Early first feeding Atlantic salmon exhibited a significantly higher mean heterozygosity, grew faster at ambient water temperature (April to November) and a significantly higher proportion adopted the early freshwater maturation (age 0+ years, male fish) or early migrant (age 1+ years, mainly female fish) strategies compared to late first feeding Atlantic salmon. Elevated water temperatures over the winter (December to April, >10·5° C) provided additional growth opportunity allowing previously mature male parr (mainly early first feeders) and lower modal group parr (mainly late first feeders) to adopt the early migrant strategy by the following spring.
Document Type: Research Article
Affiliations: 1: School of Ocean Sciences, University of Wales-Bangor, Askew Street, Menai Bridge, Anglesey LL59 5AB, U.K. and 2: Universidad de Oviedo, Departomento de Biologí a Funcional, Area de Genética, Julian Claverí a 6, 33071 Oviedo, Asturias, Spain
Publication date: February 1, 2003