Subject: RESEARCHER RECORDS UNUSUAL ACTIVITIES OF NZ KILLER WHALES (fwd)

Mike Williamson (pita@www1.wheelock.edu)
Fri, 15 Aug 1997 16:32:47 -0400 (EDT)

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---------- Forwarded message ----------
Date: Fri, 15 Aug 1997 19:26:32 +1200
From: Terry Hardie <terry@bytes.gen.nz>
Reply-To: Marine Mammals Research and Conservation Discussion
     <MARMAM@UVVM.UVIC.CA>
To: MARMAM@UVVM.UVIC.CA
Subject: RESEARCHER RECORDS UNUSUAL ACTIVITIES OF NZ KILLER WHALES

15-Aug-97 12:39 pm Regular  National

RESEARCHER RECORDS UNUSUAL ACTIVITIES OF NZ KILLER WHALES


   (Eds: photos available from Focus Photo Library, in Auckland,
09-3580797, although none shows ``frisbee'' tossing.)

   By Robert Lowe of NZPA
   Auckland, Aug 15 - Killer whales in New Zealand waters often dig
in the seafloor for stingray before surfacing and tossing their
catch around ``like a frisbee'', according to an Auckland
University researcher.
   Whangarei-based Ingrid Visser, some of whose results have been
published in the latest issue of the British magazine New Scientist,
said New Zealand ORCA whales appeared to be unique on at least two
counts.
   While there had been reports of the whales elsewhere catching
stingray, the New Zealand population specialised in preying on ray
fish as part of their diet, she said.
   ``And they are digging for the stingray, which no other
population of ORCA in the world has been reported to do,'' she told
NZPA today.
   Miss Visser has been doing research on the species in New Zealand
waters for the past six years and is writing her doctorate thesis.
   On the whales' feeding habits, she said they at times had mud
stuck on their faces as far back as the blowhole, suggesting they
had dug more than a metre deep during their ``benthic [seafloor]
foraging''.
   ``They bring the stingray up to the surface and they'll flick
their heads and toss it in the air -- not always, but it's fairly
common,'' she said.
   ``It's quite incredible to watch and sometimes they'll toss the
stingray 10m from one animal to another.''
   Miss Visser said the process could last from moments to
half-an-hour but, while she had witnessed it, she was still trying
to confirm the reasons behind it.
   ``It may be a case of repositioning the stingray, because it does
have a sting, and it may have something to do with teaching their
young,'' she said.
   ``It may just be for display, or maybe they're taking turns to
carry the food around. At this stage, I really don't know.''
   During her research, Miss Visser began the first catalogue of
orcas in New Zealand waters, and has recorded 125 in photographs.
   There had been no previous population count and therefore no
accurate indication of how many there were, where they went or what
they fed on.
   Miss Visser said it was important to know more about orcas
because of their position in the marine hierarchy.
   ``They are the top predator and are at the apex of the ecology of
the ocean,'' she said.
   ``So they're a key indicator species and we need to get basic
information about them before we can monitor whether their numbers
are increasing or declining.''

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