ICES CM 2012/E
Putting turbot on the map: environmental determinants, philopatry and high dispersal potential
shed new light on population structure
Sara G. Vandamme, Gregory E. Maes, Els Torreele, Johan Robbens and Filip A.M. Volckaert
Research agrees that major declines in stock status are common, including many flatfish stocks. Despite
the large human impact on fish stocks, both directly and indirectly, the source of degradation cannot be
understood and successfully controlled, without understanding the behaviour of individuals and their
interaction with these changes. In the past few years, many studies have suggested that several
mechanisms may explain how population structure evolves in an environment without obvious physical
boundaries to gene flow. First of all, currents may be complex and oceanographic eddies and fronts may
prevent mixing and diffusion of pelagic larvae. Moreover, hydrodynamic and bathymetric barriers have
been shown to influence population structure of some marine organisms. Secondly, as a result of the
historical separation of ocean basins and persistent oceanographical constraints, phylogeographical
structure may persist. Finally, environmental transitions have also been associated with genetic
divergence, suggesting that populations are locally adapted to their native environment.
Here, we investigate the population structure of turbot at local and microgeographical scales in the
northeast Atlantic Ocean. Turbot (Scophthalmus maximus L.) has a broad geographical distribution and
distinct ecological preferences. The diversity of life-history strategies across its range offer an
opportunity to evaluate their effect on the genetic divergence of populations. We evaluate through
spatio-temporal sampling and analysis of EST-markers the subtle structure of turbot. This strategy
permits us to make inferences about the evolutionary dynamics of putative adaptive population
divergence and provided unique information about the relative importance of various evolutionary and
environmental forces at fine geographical scales. Moreover, short-term temporal sampling provided
insights into the stability of previously observed regional genetic breaks.
Keywords: Turbot , Northeast Atlantic Ocean, Population structure, Seascape genetics
Contact author:
Sara Vandamme
Institute for Agricultural and Fisheries Research
Ankerstraat 1, 8400 Oostende Belgium
E-mail: sara.vandamme@ilvo.vlaanderen.be
and
Katholieke Universiteit Leuven
Laboratory of Animal Diversity and Systematics
Ch. de Beriotstraat 32, 3000 Leuven, Belgium