PIFSC & HIHWNMS, Cetacean Surveys, Visual and genetic surveys for odontocete cetaceans in American Samoa 2003-06

NOAA Pacific Islands Fisheries Science Center
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

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.

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Overview

Attributes described below represent those in the original dataset provided by the provider.
Only minimum required attributes are visible and downloadable online. Other attributes may be obtained upon provider's permission.

Attributes in dataset

Attribute (table column)	Description
survey_id	Survey ID
sighting_no	Sighting #
date	Date
species	Species name recorded
sp_tsn	ITIS Taxonomic serial number
common	Common name
photo_coverage	Photo coverage
effort_status	Effort (On/Off)
time	Time Begin (up to minutes)
time_end	Time End (up to minutes)
latitude	Begin Lat
longitude	Begin Long
end_lat	End Lat
end_long	End Long
count_min	Total Min
count_best	Total Best; Some records have no value (n/a)
obs_count	Total Max; this is the count used in OBIS-SEAMAP
calves_min	Calves Min
calves_best	Calves Best
calves_max	Calves Max
yoy_min	Young of the year Min
yoy_best	Young of the year Best
yoy_max	Young of the year Max
behavior	Behavior Notes
biopsy	Biopsy
biopsy_details	Biopsy Details
total_catalog_id	Total Catalog ID
total_no_id	Total No ID
total_fin_best	Total Fin Best
beaufort	Beaufort Scale (available only for OES 06-03_xx)
swell	Swell Height (available only for OES 06-03_xx)
wind_speed	Wind Speed (available only for OES 06-03_xx)
notes	Notes (available only for OES 06-03_xx)
geom	definition not provided
oid	Unique ID number (generated by SEAMAP)