engleski

A tale of two seas: contrasting patterns of population structure in the small-spotted catshark across Europe

Elasmobranchs represent important components of marine ecosystems, but they can be vulnerable tooverexploitation. This has driven investigations into the population genetic structure of large-bodiedpelagic sharks, but relatively little is known of population structure in smaller demersal taxa, whichare perhaps more representative of the biodiversity of the group. This study explores spatial populationgenetic structure of the small-spotted catshark (Scyliorhinus canicula), across European seas. The resultsshow significant genetic differences among most of the Mediterranean sample collections, but nosignificant structure among Atlantic shelf areas. The data suggest the Mediterranean populations arelikely to have persisted in a stable and structured environment during Pleistocene sea-level changes.Conversely, the Northeast Atlantic populations would have experienced major changes in habitatavailability during glacial cycles, driving patterns of population reduction and expansion. The data alsoprovide evidence of male-biased dispersal and female philopatry over large spatial scales, implyingcomplex sex-determined differences in the behaviour of elasmobranchs. On the basis of this evidence, we suggest that patterns of connectivity are determined by trends of past habitat stability that providesopportunity for local adaptation in species exhibiting philopatric behaviour, implying that resilience ofpopulations to fisheries and other stressors may differ across the range of species.

elasmobranch, sex-biased dispersal, fisheriesmanagement, Scyliorhinidae, lesser spotteddogfish

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