[MARMAM] Abstract: Hawaii killer whales

Robin Baird RWBaird at cascadiaresearch.org
Mon Jul 31 10:03:11 PDT 2006


New publication:
 
Baird, R.W., D.J. McSweeney, C. Bane, J. Barlow, D.R. Salden, L.K.
Antoine, R.G. LeDuc and D.L. Webster. 2006. Killer whales in Hawaiian
waters: information on population identity and feeding habits. Pacific
Science 60:523-530.
 
Abstract
 
Killer whales (Orcinus orca) have only infrequently been reported from
Hawaiian waters, and most of what is known about killer whales
world-wide comes from studies in coastal temperate waters. Here we
document 24 records of killer whales from within the Hawaiian Exclusive
Economic Zone between 1994 and 2005. Killer whales were recorded 10
months of the year, most around the main Hawaiian Islands. While there
were slightly more records than expected during the period when humpback
whales are abundant around the islands, there is likely an increase in
sighting effort during this period. Killer whales were documented
feeding on both a humpback whale and cephalopods, and two species of
small cetaceans were observed fleeing from killer whales. Although it is
possible there are both marine mammal-eating and cephalopod-eating
populations within Hawaiian waters, it seems more likely that Hawaiian
killer whales may not exhibit foraging specializations as documented for
coastal temperate populations, given the lower productivity and thus
reduced selective pressure for specialization in tropical waters. Saddle
patch pigmentation patterns were generally fainter and narrower than for
those seen in killer whales from the temperate coastal North Pacific,
though were most similar to the mammal-eating form of killer whale from
those areas. Analysis of skin samples from two animals indicated two
mitochondrial haplotypes, one identical to the "Gulf of Alaska transient
2" haplotype (a mammal-eating form), and the other a new haplotype one
base different from haplotypes found for mammal-eating killer whales in
coastal Alaskan waters. While more samples are needed, including samples
from intervening areas, we suggest that killer whales around the
Hawaiian Islands are likely isolated from populations in coastal
temperate areas.
 
PDF copies are available at
http://www.cascadiaresearch.org/robin/hawaii.htm
 
 
 
========================================================
Robin W. Baird, Ph.D.
Research Biologist
Cascadia Research Collective
218 1/2 W. 4th Avenue
Olympia, WA
98501 USA
 
Phone 1-360-943-7325
Fax 1-360-943-7026
e-mail: rwbaird at cascadiaresearch.org
www.cascadiaresearch.org/robin/robin.htm
 




More information about the MARMAM mailing list