Countergradient variation in body shape of Atlantic cod: implications for stock structure studies1 ...

• Main Authors: Marcil, Julie, Swain, Douglas P., Hutchings, Jeffrey A.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: ASC 2005 - K - Theme session 2024
• Subjects: Fisheries and aquaculture; Pressures, impacts, conservation, and management; atlantic cod; Gadus morhua
• Online Access: https://dx.doi.org/10.17895/ices.pub.25350148; https://ices-library.figshare.com/articles/conference_contribution/Countergradient_variation_in_body_shape_of_Atlantic_cod_implications_for_stock_structure_studies1/25350148

No abstracts are to be cited without prior reference to the author.Genetic and environmental influences on the phenotype can be cogradient, with environmental influences reinforcing the genetic differences between populations, or countergradient, with genetic differences counteracting environmental effects. Morphological traits such as body shape are generally thought to exhibit co-gradient variation. However, we present a striking example of countergradient variation in body shape of juvenile Atlantic cod (Gadus morhua). We compared four populations, one spawning in winter (4X) and three spawning in early summer (3L, 3Ps, 4T). No difference in body shape occurred between wild-reared juveniles from winter-spawning (4X) versus summer-spawning (3L) populations. However, when reared in common laboratory environments, striking shape differences occurred between 4X juveniles and those from the three summer-spawning populations. This indicates that genetic divergence underlies the phenotypic similarity of these ...