Stock structure of black oreo has been studied and “small but significant difference in mtDNA haplotype frequencies” were found between New Zealand and Australia. Other specific study on NZ waters found differences among some of the areas assumed but results are not yet conclusive so the following areas identified are used for assessment and management (MPI, 2014a). Black oreo and smooth oreos are assessed separately but managed jointly:

1. West Chatham Rise OEO 3A (Black Oreo) - managed as West Chatham Rise OEO 3A (black and smooth oreos)
2. East Chatham Rise OEO 4 (Black Oreo) - managed as East Chatham Rise OEO 4 (black and smooth oreos)
3. Pukaki Rise OEO 6 (Black Oreo) - managed as New Zealand SW and Subantarctic OEO 1 and OEO 6 (black and smooth oreos)