Abstract: individual range use in bottlenose whales (fwd)

From: Pita Admininstrator (pita@whale.wheelock.edu)
Date: Thu Jan 24 2002 - 11:24:03 EST


---------- Forwarded message ----------
Date: Tue, 22 Jan 2002 13:30:17 -0400
From: Robin W Baird <rwbaird@is.dal.ca>
Reply-To: Marine Mammals Research and Conservation Discussion
    <MARMAM@UVVM.UVIC.CA>
To: MARMAM@UVVM.UVIC.CA
Subject: Abstract: individual range use in bottlenose whales

Since Sascha is in the field I am posting this abstract for her.

Hooker, S.K., H. Whitehead, S. Gowans and R.W. Baird. 2002. Fluctuations
in distribution and patterns of individual range use of northern
bottlenose whales. Marine Ecology Progress Series 225:287-297.

Abstract

This study investigated the pattern and scale of distribution, movements
and range use of the northern bottlenose whale Hyperoodon ampullatus above
a submarine canyon, the Gully, off eastern Canada between 1988 and 1998.
Locations and individual identification photographs were collected during
encounters with whales. Whales showed a discrete distribution within the
canyon associated with water depth (500 to 1500 m) and relatively steep
topography. Encounter rate and distribution showed some variation between
years. Changes in distribution were observed toward the north or south of
the canyon, probably a consequence of changes in prey distribution.
Individual whales within the canyon displaced 4 to 5 km over 24 h, with
negligible further increase in displacement over time scales up to 20 d
(their approximate residency period). Short-term VHF radio-tracking of 5
individuals provided an independent source of movement data, showing
displacements of approximately 2 km in 1 h and 5 to 10 km in 1 d. The
relative lack of movement observed for these whales supports the
hypothesis that the canyon contains a profitable and localized food
source. Movements of whales best fit a model of short-term residence
within ranges of approximately 25 km-squared, although the range size of
mature males was smaller than that of females and immature males.
Photo-resightings were also used to investigate variation in the positions
of individual whales within the Gully. Within years, individuals showed
some separation of ranges associated with periods of high whale abundance,
but there was no separation between different age-sex classes. Between
years, mature males showed consistent spatial orientations relative to
each other, suggesting preferred locations possibly related to mating
opportunities.

Key words: foraging ecology, cetacean, submarine canyon, movements, range,
territoriality.

PDF reprints may be obtained by writing to rwbaird@is.dal.ca

======================================================================
Robin W. Baird, Ph.D.
Post-doctoral Fellow, Biology Department, Dalhousie University
and
Cetacean and Sea Turtle Team, NMFS, NOAA Beaufort Lab
101 Pivers Island Road, Beaufort, NC 28516 USA
Phone: 252-728-8601
Fax: 252-728-8784
e-mail: robin.baird@noaa.gov or rwbaird@is.dal.ca
http://shrimp.bea.nmfs.gov/
http://is.dal.ca/~whitelab/rwb/robin.htm



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