A preliminary photo-identification study of bottlenose dolphin (Tursiops truncatus) in Hauraki Gulf, New Zealand

Analysis of photographs of individual bottlenose dolphin (Tursiops truncatus) taken in Hauraki Gulf, New Zealand between 2000 and 2003 resulted in 162 uniquely identifiable individuals being included in the Hauraki Gulf bottlenose dolphin photo-identification catalogue. Seventy percent of these catalogued animals were sighted more than once, with sighting frequency ranging from one to eleven encounters. Seasonality was apparent inside the gulf with the majority of observations occurring betweenApril and June, inclusively. Comparison of individual photo-identification catalogues between Bay of Islands and Hauraki Gulf resulted in 59% of the individuals catalogued in Hauraki Gulf being confirmed as occurring in both locations. However, 41% of individuals did not match with animals in the Bay of Islands catalogue, possibly indicating a larger population size than previously suggested for the northeastern region of the North Island, and/or the possibility of individuals overlapping in range between at least two sites along this coastline.