Subject: Abstract: Humpback Whales (fwd)

Mike Williamson (pita@www1.wheelock.edu)
Sat, 3 Jan 1998 10:36:07 -0500 (EST)

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---------- Forwarded message ----------
Date: Wed, 31 Dec 1997 12:25:33 -1000
From: Alison Craig <acraig@hawaii.edu>
Reply-To: Marine Mammals Research and Conservation Discussion
     <MARMAM@UVVM.UVIC.CA>
To: MARMAM@UVVM.UVIC.CA
Subject: Abstract: Humpback Whales


Craig, A.S. & Herman, L.M.  1997.  Sex differences in site fidelity and
migration of humpback whales (Megaptera novaeangliae) to the Hawaiian
Islands.  Canadian Journal of Zoology 75: 1923-1933.

Humpback whales (Megaptera novaeangliae) perform extensive seasonal
migrations between high-latitude summer feeding grounds and low-latitude
winter reproductive grounds. To investigate gender-related site fidelity
to the Hawaiian Islands, an important wintering area for North Pacific
humpback whales, photographically based resight histories of 224 females
and 416 males observed in Hawai'i from 1976 through 1991 were compiled.
Results indicated that the mean number of years in which they were seen
was higher for males than for females, that the probability of an
individual being resighted across years was higher for males than for
females, and that more males than females were seen in consecutive years.
Potential sources of bias favoring the photographic capture of males were
considered, but none were judged to be significant contributors to the
results obtained. It was proposed instead that not all females undertake
or complete the migration to the winter grounds each year. Because of the
high energy costs of migration and reproduction, some females may
overwinter in high latitudes, while others may become pregnant en route to
the area traditionally associated with breeding and return to the feeding
grounds before arriving at the terminal winter destination.

Reprint requests to:    Alison S. Craig
                        Kewalo Basin Marine Mammal Laboratory
                        1129 Ala Moana Blvd.
                        Honolulu,  HI 96814
                        USA.

                        acraig@hawaii.edu