Hector's dolphin (C. hectori
) is endemic to New Zealand
waters (Dawson and Slooten 1988). The North Island subpopulation (C. h. maui
) is currently restricted to the west coast of the North Island of New Zealand, between Taranaki and Ninety Mile Beach (Russell 1999; Baker et al.
2002; Slooten et al.
2005, 2006). The range of the subspecies has undergone a marked reduction (Dawson et al.
2001; Slooten et al.
2005). Previous sightings off the east coast of the North Island (e.g., Russell 1999) suggest either that there used to be a much larger contiguous population or that a separate subpopulation on the North Island
has already become extinct.