Background. White-chinned petrels are caught as fisheries bycatch more than almost any other seabird on the planet, but taxonomic uncertainty hinders risk assessment and species management efforts. The focus of uncertainty is in boundaries of taxa in the New Zealand region. We tested whether any NZ colonies (Antipodes, Auckland, and Campbell Islands) are distinct from each other and/or from colonies around other sectors of the Southern Ocean.
Methods. We obtained DNA sequence data for the mitochondrial cytochrome b gene (~1143 base pairs, bp), the nuclear intron β-fibrinogen 7th intron (~933 bp), and the mitochondrial control region domain I (~519 bp). Sequences were investigated using maximum-likelihood, Bayesian and distance analyses.
Results. These data did not support a separate taxon for the Antipodes breeding population. Instead, white-chinned petrels from all NZ islands clustered together and a second, separate taxon included all other island colonies. However, whole-genome data (~80,000 SNPs) revealed a mismatch: SNPs confirmed the NZ regional taxon seen with other markers, and showed a previously unsuspected split between colonies in the South Atlantic (South Georgia and Falkland Islands) and southern Indian Ocean (Marion, Crozet and Kerguelen Islands).
Conclusions. These groupings indicate three ocean-basin level genetic management units for white-chinned petrels. The challenge: to manage the vast fisheries bycatch problem according to biologically relevant boundaries that span political boundaries.
Funding. NZ Department of Conservation’s Conservation Services Programme (to B.R.), Otago Museum Linnaeus Taxonomy Fellowship and Department of Zoology allocation (to K.R.H.), and Ministry for Business Innovation and Employment project funding (to J.M.).