Visual and genetic surveys for odontocete cetaceans in American Samoa 2003-06

Marie C. Hill

doi:10.15468/jdas39

Visual and genetic surveys for odontocete cetaceans in American Samoa 2003-06

Citation

Chapla, M. 2008. Visual and genetic surveys for odontocete cetaceans in American Samoa 2003-06. Data downloaded from OBIS-SEAMAP (http://seamap.env.duke.edu/dataset/466) on yyyy-mm-dd. https://doi.org/10.15468/jdas39 accessed via GBIF.org on 2024-12-12.

Description

Original provider: Pacific Islands Fisheries Science Center & Hawaiian Islands Humpback Whale National Marine Sanctuary Dataset credits: Marie Chapla Hill, Joint Institute for Marine and Atmospheric Research, Research Corporation for the University of Hawaii David Johnston, Duke University Marine Laboratory David Mattila, Hawaiian Islands Humpback Whale National Marine Sanctuary Jooke Robbins, Provincetown Center for Coastal Studies Abstract: Very little is known about the species composition, distribution, abundance, and stock structure of odontocete cetaceans inhabiting the United States Exclusive Economic Zone's (EEZ) waters of American Samoa. While some information on species presence in this region has been gleaned from anecdotal sightings and whaling and stranding records, the diversity of odontocete cetaceans in the waters of American Samoa has never been formally investigated. We conducted a series of small boat photo-identification and biopsy surveys for cetaceans in the nearshore waters of Tutuila during 2003-2006. As well, ship-based visual surveys were conducted in the waters surrounding the Manu'a Islands, Rose Atoll, and Swains Island in the summer of 2006. A total of 52 groups of odontocete cetaceans were encountered during small boat surveys, including spinner dolphins (Stenella longirostris), rough-toothed dolphins (Steno bredanensis), sperm whales (Physeter macrocephalus), false killer whales (Pseudorca crassidens), bottlenose dolphins (Tursiops sp.), dwarf sperm whales (Kogia sima), and unidentified odontocetes. A total of six groups of cetaceans were encountered during ship-based surveys, including false killer whales, pilot whales (Globicephala macrorhynchus), sperm whales, and unidentified odontocetes. Photographs, taken during both small boat and ship-based surveys, were analyzed for quality, and individuals with distinctive markings were selected for entry into the photo-identification catalogue. The resulting catalog includes 46 spinner dolphins, 41 rough-toothed dolphins, 2 bottlenose dolphins, 5 false killer whales, 4 pilot whales, 1 dwarf sperm whale, and 4 sperm whales. Thirteen (13) spinner dolphins and 14 rough-toothed dolphins were sighted in multiple years. For spinner dolphins, genetic data were used to estimate genetic diversity and effective population size and to compare these values with those of spinner dolphins in the Hawaiian Islands. Diversity and populations size estimates were higher in American Samoa than in Hawai'i, suggesting a larger population size at American Samoa.

Purpose

Not available

Sampling Description

Study Extent

NA

Sampling

NA

Method steps

NA

Additional info

marine, harvested by iOBIS

Taxonomic Coverages

Scientific names are based on the Integrated Taxonomic Information System (ITIS).

Globicephala macrorhynchus
common name: Short-finned Pilot Whale rank: species
Kogia sima
common name: Dwarf Sperm Whale rank: species
Megaptera novaeangliae
common name: Humpback Whale rank: species
Physeter macrocephalus
common name: Sperm Whale rank: species
Pseudorca crassidens
common name: False Killer Whale rank: species
Stenella longirostris
common name: Spinner Dolphin rank: species
Steno bredanensis
common name: Rough-toothed Dolphin rank: species
Tursiops
common name: bottlenose dolphins rank: genus
Delphinidae
common name: dolphins rank: family
Delphinidae
common name: dolphins rank: family

Geographic Coverages

Oceans

Bibliographic Citations

Contacts

Marie C. Hill
originator
position: Primary contact
Pacific Islands Fisheries Science Center
email: Marie.Hill@noaa.gov

OBIS-SEAMAP
metadata author
Marine Geospatial Ecology Lab, Duke University
A328 LSRC building
Durham
27708
NC
US
email: seamap-contact@duke.edu
homepage: http://seamap.env.duke.edu

OBIS-SEAMAP
distributor
Marine Geospatial Ecology Lab, Duke University
A328 LSRC building
Durham
27708
NC
US
email: seamap-contact@duke.edu
homepage: http://seamap.env.duke.edu

Marie C. Hill
owner
position: Primary contact
Pacific Islands Fisheries Science Center
email: Marie.Hill@noaa.gov

Marie C. Hill
administrative point of contact
position: Primary contact
Pacific Islands Fisheries Science Center
email: Marie.Hill@noaa.gov