Data from: Genetic diversity and population structure of the Pelagic Thresher Shark (Alopias pelagicus) in the Pacific Ocean: evidence for two evolutionarily significant units

There has been an increasing concern about shark overexploitation in the
last decade, especially for open ocean shark species, where there is a
paucity of data about their life histories and population dynamics. Little
is known regarding the population structure of the pelagic thresher shark,
Alopias pelagicus. Though an earlier study using mtDNA control region
data, showed evidence for differences between eastern and western Pacific
populations, the study was hampered by low sample size and sparse
geographic coverage, particularly a lack of samples from the central
Pacific. Here, we present the population structure of Alopias pelagicus
analyzing 351 samples from six different locations across the Pacific
Ocean. Using data from mitochondrial DNA COI sequences and seven
microsatellite loci we found evidence of strong population differentiation
between western and eastern Pacific populations and evidence for
reciprocally monophyly for organelle haplotypes and significant divergence
of allele frequencies at nuclear loci, suggesting the existence of two
Evolutionarily Significant Units (ESU) in the Pacific Ocean.
Interestingly, the population in Hawaii appears to be composed of both
ESUs in what seems to be clear sympatry with reproductive isolation. These
results may indicate the existence of a new cryptic species in the Pacific
Ocean. The presence of these distinct ESUs highlights the need for revised
management plans for this highly exploited shark throughout its range.