Data from: Widespread gene flow between oceans in a pelagic seabird species complex

Global-scale gene flow is an important concern in conservation biology as
it has the potential to either increase or decrease genetic diversity in
species and populations. Although many studies focus on the gene flow
between different populations of a single species, the potential for gene
flow and introgression between species is understudied, particularly in
seabirds. The only well-studied example of a mixed-species, hybridizing
population of petrels exists on Round Island, in the Indian Ocean.
Previous research assumed that Round Island represents a point of
secondary contact between Atlantic (Pterodroma arminjoniana) and Pacific
species (Pterodroma neglecta and Pterodroma heraldica). This study uses
microsatellite genotyping and tracking data to address the possibility of
between-species hybridization occurring outside the Indian Ocean.
Dispersal and gene flow spanning three oceans were demonstrated between
the species in this complex. Analysis of migration rates estimated using
bayesass revealed unidirectional movement of petrels from the Atlantic and
Pacific into the Indian Ocean. Conversely, structure analysis revealed
gene flow between species of the Atlantic and Pacific oceans, with
potential three-way hybrids occurring outside the Indian Ocean.
Additionally, geolocation tracking of Round Island petrels revealed two
individuals travelling to the Atlantic and Pacific. These results suggest
that interspecific hybrids in Pterodroma petrels are more common than was
previously assumed. This study is the first of its kind to investigate
gene flow between populations of closely related Procellariiform species
on a global scale, demonstrating the need for consideration of widespread
migration and hybridization in the conservation of threatened seabirds.