title: Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species.
abstract: Understanding the key drivers of population connectivity in the marine environment is essential for the effective management of natural resources. Although several different approaches to evaluating connectivity have been used, they are rarely integrated quantitatively. Here, we use a 'seascape genetics' approach, by combining oceanographic modelling and microsatellite analyses, to understand the dominant influences on the population genetic structure of two Antarctic fishes with contrasting life histories, Champsocephalus gunnari and Notothenia rossii. The close accord between the model projections and empirical genetic structure demonstrated that passive dispersal during the planktonic early life stages is the dominant influence on patterns and extent of genetic structuring in both species. The shorter planktonic phase of C. gunnari restricts direct transport of larvae between distant populations, leading to stronger regional differentiation. By contrast, geographic distance did not affect differentiation in N. rossii, whose longer larval period promotes long-distance dispersal. Interannual variability in oceanographic flows strongly influenced the projected genetic structure, suggesting that shifts in circulation patterns due to climate change are likely to impact future genetic connectivity and opportunities for local adaptation, resilience and recovery from perturbations. Further development of realistic climate models is required to fully assess such potential impacts.
authors.affiliation: British Antarctic Survey Cambridge, UK.
authors.forename: Emma F
authors.initials: EF
authors.lastname: Young
authors.affiliation: British Antarctic Survey Cambridge, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Belchier
authors.affiliation: School of Aquatic and Fishery Sciences, University of Washington Seattle, WA, USA.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Hauser
authors.affiliation: NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield Sheffield, UK.
authors.forename: Gavin J
authors.initials: GJ
authors.lastname: Horsburgh
authors.affiliation: British Antarctic Survey Cambridge, UK.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Meredith
authors.affiliation: British Antarctic Survey Cambridge, UK.
authors.forename: Eugene J
authors.initials: EJ
authors.lastname: Murphy
authors.affiliation: School of Biological Sciences, Bangor University Bangor, Gwynedd, UK.
authors.forename: Sonia
authors.initials: S
authors.lastname: Pascoal
authors.affiliation: NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield Sheffield, UK ; School of Biological Sciences, Bangor University Bangor, Gwynedd, UK ; Present address: Department of Zoology, University of Otago Dunedin, 9054, New Zealand.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Rock
authors.affiliation: School of Biological Sciences, Bangor University Bangor, Gwynedd, UK ; Present address: Campus Agronomique BP 709-97387, Kourou Cedex, France.
authors.forename: Niklas
authors.initials: N
authors.lastname: Tysklind
authors.affiliation: School of Biological Sciences, Bangor University Bangor, Gwynedd, UK.
authors.forename: Gary R
authors.initials: GR
authors.lastname: Carvalho
keywords: Champsocephalus gunnari; Individual-based Modelling; Notothenia rossii; Scotia Sea; connectivity; ocean circulation; planktonic dispersal; population genetics