Mitochondrial DNA analysis reveals genetic structure in two New Zealand Cook's petrel (Pterodroma cookii) populations

The endangered Cook's petrel (Pterodroma cookii) is restricted to two separated populations at the extremes of its former range across New Zealand. Prior work revealed morphological, foraging, and reproductive isolation between these two remnant populations. To aid the conservation management of the species, additional information is required on the genetic structure of Cook's petrel. We used mitochondrial DNA sequences (Cytochrome Oxidase subunit 1 gene), collected from 26 and 19 Cook's petrel breeding on Little Barrier Island (LBI) and Codfish Island (CDF), respectively, for this preliminary study. We uncovered distinct population genetic structure with analysis of molecular variance suggesting genetic isolation of the populations. Levels of genetic variation were higher in the LBI population (four haplotypes present; h = 0.34 and π = 0.10) whereas the CDF population had only one haplotype that was distinct from the LBI population. Our results indicate that Cook's petrel constitute two distinct management units for which conservation of genetic as well as behavioural and morphological diversity should be a priority. Further genetic studies using nuclear markers are recommended.