Differences in early developmental rate and yolk conversion efficiency in offspring of trout with alternative life histories

Travis E Van Leeuwen,Neil B Metcalfe,Colin E Adams,Shaun S Killen

doi:10.1111/eff.12281

Abstract

AbstractPartial migration, in which some individuals of a population migrate while other individuals remain resident, is generally associated with ontogenetic shifts to better feeding areas or as a response to environmental instability, but its underlying mechanisms remain relatively unknown. Brown trout (Salmo trutta) exhibit partial migration, with some individuals remaining in freshwater (freshwater resident) while others undertake an anadromous migration, where they spend time at sea before returning to breed in freshwater (migrant). We reared full‐sibling groups of offspring from freshwater‐resident and anadromous brown trout from the same catchment in the laboratory under common garden conditions to examine potential differences in their early development. Freshwater‐resident parents produced eggs that were slower to hatch than those of anadromous parents, but freshwater‐resident offspring were quicker to absorb their yolk and reach the stage of exogenous feeding. Their offspring also had a higher conversion efficiency from the egg stage to the start of exogenous feeding (so were larger by the start of the fry stage) than did offspring from anadromous parents despite no difference in standard metabolic rate, maximal metabolic rate or aerobic scope. Given these differences in early development, we discuss how the migration history of the parents might influence the migration probability of the offspring.

Highlights

IntroductionThere is variation in the propensity of individuals from a single population to migrate between habitats (the phenomenon of ‘partial migration’, see reviews in Chapman et al 2011; Dodson et al 2013)
In many taxa, there is variation in the propensity of individuals from a single population to migrate between habitats
The degree of adversity and assessment of future fitness will depend on the particular environmental conditions that are experienced at the time and whether or not partial migration is fixed or flexible

Summary

Introduction

There is variation in the propensity of individuals from a single population to migrate between habitats (the phenomenon of ‘partial migration’, see reviews in Chapman et al 2011; Dodson et al 2013). The commonest form of this intraspecific variation in movement patterns is nonbreeding partial migration (sensu Chapman et al 2011), where migrants and residents breed in sympatry but segregate during. Body size may affect the selection pressures for/against migration, as larger individuals may generally have less to gain from migration (Dodson et al 2013; though see Brodersen et al 2008 for an exception) as they usually have advantages of a higher competitive ability and/or lower risk of starvation and predation (Chapman et al 2011)

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Conclusion