Early predictors of life‐history events: the link between first feeding date, dominance and seaward migration in Atlantic salmon, <i>Salmo salar</i> L.

Abstract

Previous studies have suggested that the earliest fry to emerge from a salmonid redd may have an advantage in the subsequent competition for feeding sites, partly through a ‘prior residence’ effect. Here we examined whether there was any relationship between the relative date of first feeding and subsequent dominance status and growth in a sibling group of Atlantic salmon, Salmo salar L., fry. Earlier‐feeding fry were dominant over their later‐feeding siblings (controlling for prior residence), despite not being any larger. However, these early fish soon established and then maintained a size advantage. This led to an increased probability of early‐feeding fish migrating to sea at age 1 year (rather than 2 or more). Thus a difference of less than 1 week in the relative timing of first feeding can translate into a year's difference in the timing of migration.