Near‐shore distribution and abundance of dolphins along the West Coast of the South Island, New Zealand

New Zealand Journal of Marine and Freshwater Research (Impact Factor: 0.88). 03/1998; 32(1):105-112. DOI: 10.1080/00288330.1998.9516809

ABSTRACT Compared to other stretches of the New Zealand coast, very little is known about the cetacean fauna off the West Coast of the South Island. The purpose of this paper is to describe the near‐shore distribution and abundance of dolphins in that area by summarising the results of two major studies. Between February 1995 and February 1997, 97 day trips were undertaken from Westport, Greymouth, and Jackson Bay in a small boat to survey the near‐shore distribution of dolphins. Between July 1994 and February 1997, 283 field days were spent on the water in Doubtful Sound studying the local bottlenose dolphin (Tursiops truncatus) population of c. 63 individuals. At the same time, three longer surveys were undertaken into other fiords of Fiordland which indicated the presence of further populations. Altogether, five delphinid species were recorded in various abundances. Small‐medium‐sized groups of Hector's dolphins (Cephalorhynchus hectori) with 1–60 individuals were observed in almost all areas of Westland in winter as well as in summer. Maximum densities peaked at 5–18 individuals per nautical mile of coastline between Cape Foulwind and Hokitika. Dusky and common dolphins (Lagenorhynchus obscurus and Delphinus delphis) occurred almost exclusively in summer in groups of 2–150 individuals, often with calves, especially at Cape Foulwind and Jackson Head. Bottlenose dolphins (Tursiops truncatus) and killer whales (Orcinus orca) were observed rarely off Westland, but occurred more frequently in Fiordland.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    New Zealand Journal of Marine and Freshwater Research - N Z J MAR FRESHWATER RES. 01/2008; 42(4):465-472.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: New Zealand is the southernmost limit of the common dolphin's (genus Delphinus) distribution in the Pacific Ocean. In this area, common dolphins occur in both coastal and oceanic habitats, exhibit seasonal and resident occurrence, and present high morphological variability. Here we investigated the population structure and the taxonomic identity of common dolphins (Delphinus sp.) within New Zealand waters using 14 microsatellite loci, 577 bp of the mtDNA control region, and 1,120 bp of the mtDNA cytochrome b gene across 90 individuals. We found high genetic variability and evidence of population expansion. Phylogenetic analyses conducted to clarify the taxonomic status of New Zealand common dolphins did not show any clustering reflecting geographic origin or morphotypes. The microsatellite analysis showed genetic differentiation between Coastal and Oceanic putative populations, while mtDNA revealed significant genetic differentiation only between the Hauraki Gulf and other putative groups. Our results suggest that differences in habitat choice and possible female site fidelity may play a role in shaping population structure of New Zealand common dolphins.
    Marine Mammal Science 01/2014; 30(1). · 2.13 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Regional populations of bottlenose dolphins (Tursiops truncatus) around New Zea- land are genetically isolated from each other and the species was recently classified as nationally endangered based on relatively small population sizes and reports of high calf mortality. Here, we estimate the abundance and trends in one of these regional populations, the Bay of Islands, using a photo-identification database collected from 1997 to 1999 and from 2003 to 2006, containing a total of 3,841 records of 317 individual dolphins. Estimates of abundance obtained with the robust design fluctu- ated widely but showed a significant decline in the number of dolphins present in the bay over time (7.5% annual rate of decline). Temporary emigration was random and fluctuated considerably (c = 0.18, SE = 0.07 to c = 0.84, SE = 0.06). Appar- ent survival was estimated at 0.928 (CI = 0.911–0.942). Seasonal estimates (26 sea- sons) obtained in POPAN also showed a significant decline in abundance (5.8% annual rate of decline). Despite the decline observed in local abundance, dolphins continue to be found regularly in the Bay of Islands, suggesting that fewer dolphins use the bay on regular basis. Consequently, it seems that a change in habitat use, mortality and possibly low recruitment could underlie the apparent local decline.
    Marine Mammal Science 01/2013; · 2.13 Impact Factor


Available from
May 23, 2014