2008, Möller et al. 2011). While long-beaked common dolphins (D. capensis)

can be found in large groups in open oceanic waters (Carretta et al. 2011), typically within coastal seas they form smaller aggregations (Bernal et al. 2003, Cobarrubia and Bolaños-Jiménez 2007). Within the Hauraki Gulf, the group size and water depths in which animals are located are more akin with the long- as opposed to the short-beaked form (Stockin et al. 2008). Several studies have attempted to clarify the taxonomic status Histone Methyltransferase inhibitor of various common dolphin populations worldwide, using both morphological (e.g., Amaha 1994, Heyning and Perrin 1994, Jefferson and Van Waerebeek 2002, Samaai et al. 2005, Murphy et al. 2006) and molecular (e.g., Rosel et al. 1994, Kingston and Rosel 2004, Amaral et al. 2007a) techniques. However, the reciprocal monophyly observed between the short- and long-beak forms in the eastern North Pacific was not confirmed from worldwide genetic analyses of the genus, suggesting that the long-beaked morphotype may have evolved this website independently in different regions (Natoli et al. 2006, Amaral et al. 2012). To date, no taxonomic assessment has been conducted on New Zealand Delphinus,

although common dolphins in these waters are nominally classified as short-beaked (e.g., Gaskin 1968, Webb 2005, Slooten and Dawson 1995, Bräger and Schneider 1998, Neumann 2001a) based on the apparent absence of the long-beaked form within the South West Pacific (Heyning and Perrin 1994). However, the variation observed in morphological traits such as pigmentation (Stockin and Visser 1973) and skull morphology (Amaha 1994) gives rise to uncertainty. Putative evidence of D. capensis is provided by Bernal et al. (2003) who suggests that common dolphins exhibiting long rostra, as photographed in New Zealand by Doak (1989), likely represent the long-beaked species. Furthermore, Amaha (1994) and Jefferson and Van Waerebeek (2002) suggest neither New Zealand nor much Australian common dolphins fit neatly the morphological description of either D. delphis

or D. capensis. In this study we aimed to investigate the population structure and the taxonomic status of the New Zealand common dolphin using mitochondrial DNA (mtDNA) sequences and microsatellite markers. We tested for potential population structure of dolphins in New Zealand waters by the examination of three putative groups (Coastal, Hauraki Gulf, and Oceanic) based on the observation relative to the different habitat use: coastal vs. oceanic, and seasonal vs. resident. A total of 90 skin samples were collected from common dolphins in New Zealand waters. Of these, 44 samples were collected from stranded or fresh beach-cast carcasses, and a further 46 samples were obtained from common dolphins incidentally captured in the commercial fishery for jack mackerel (Trachurus spp.).