Moulding the ideal crab: implications of phenotypic plasticity for crustacean stock enhancement

Abstract

Abstract Numerous examples of behavioural and morphological differences between hatchery-cultured and wild individuals exist for a range of crustacean species; however, we submit that these variances are not deficiencies, but rather are adaptive responses to an unnatural rearing environment that may be detrimental in the natural environment. This phenotypic plasticity could be beneficial for stock enhancement because such plasticity suggests potential for change with adjustments to rearing protocols to achieve improved ecological competence. We examine how specific plastic responses can affect crustacean ecology through effects on predation, foraging, competition, and reproduction. For developing stock enhancement programmes, we recommend consideration of plastic phenotypic patterns before large-scale releases are initiated. Researchers can identify environmental factors that cue plasticity during hatchery rearing, determine if induced responses are ecologically influential after release into the wild, and examine the temporal scale on which phenotypic plasticity operates. Communal hatchery rearing at low-to-medium stocking densities with predator cues and natural substrates along with in situ conditioning, releases during periods of low predation risk, and coupled laboratory-field studies can contribute to improved ecological performance during stock enhancement. Finally, presentation of non-significant research results is needed to avoid bias towards hatchery–wild differences and help guide future conditioning programmes.