Data from: Atypical panmixia in a European dolphin species (Delphinus delphis); implications for the evolution of diversity across oceanic boundaries.

Despite the scarcity of geographical barriers in the ocean environment,
delphinid cetaceans often exhibit marked patterns of population structure
on a regional scale. The European coastline is a prime example, with
species exhibiting population structure across well defined environmental
boundaries. Here we undertake a comprehensive population genetic study on
the European common dolphin (Delphinus delphis, based on 492 samples and
15 loci) and establish that this species shows exceptional panmixia across
most of the study range. We found differentiation only between the eastern
and western Mediterranean, consistent with earlier studies, and here use
Approximate Bayesian Computations to explore different scenarios to
explain the observed pattern. Our results suggest that a recent population
bottleneck likely contributed significantly to the differentiation of the
Eastern Mediterranean population (in Greek waters). This interpretation is
consistent with independent census data which suggests a sharp population
decline in the recent past. The implication is that an unperturbed
population may currently show panmixia across the full study range. This
exception to the more typical pattern of population structure seen for
other regional dolphin species (and for common dolphin populations
elsewhere in the world) suggests particular ecological or life history
traits distinct to this species in European waters.