Subject: Stranded Pilot Whales

Kim Marshall (kimm@oceanalliance.org)
Wed, 20 Oct 1999 08:26:55 -0400

Question:
My name is Melissa Medford. I'm 17 years old and live in the Caribbean
island of Trinidad, on Wednesday 13th October,1999, 26 Pilot whales got
beached upon our shores. 14 of the 26 were saved including a pregnant
mother, sadly the other 12 died. Earlier this year two small whales were
also beached, one was saved the other was killed by the villagers for its
meat. I have always been wondered by these animals and have tried on many
occasions to get more information on them, unfortunately this country does
have the resources to answer my biggest question. How did these animals get
beached on our shores, and how can it be stop. I was taken by my mother to
see the ones that were left on shore, those were dead, they looked like
such great creatures and it saddens me to see them dead like this, and also
to see them die at the hands of hunters. So please if possible can you send
me some information of these creatures. To my knowledge the whales that
were beached were pilot whales.

Re: Pilot whales and why they Strand
Dear Melissa.
Pilot whales seem to be the most common type of whale to strand on beaches.
Unfortunately most stranded whales do not survive once they have beached
themselves.  In most cases they are already sick and dying or if they have
just made a mistake they suffer from the pressure of their own weight on
their organs because in the water they are weightless.  They also suffer
from overheating as they have blubber that insulates them in the water and
outside of the water causing them to overheat.  Where possible we place wet
towels and cold water on their fins and flukes when do they strand to help
keep their body temperature down.

No one really knows why whales strand but with networks managed by the
National Marine Fisheries Service and NOAA we are learning more and more
every day. Most mass strandings of whales occur with toothed whales, like
pilot whales, that live in pods with social hierarchies.  It is believed
that if the leader of the group gets sick or disoriented the others simply
follow the leader onto the shore. Others believe that if there is an
illness throughout the group they will mass strand and die so as not to
transfer disease.  Another theory is that their sonar used for navigation
may get absorbed by particulates in the water near areas with a lot of
upwelling i.e.: Cape Cod, Massachusetts in the United States, causing them
to misinterpret information and basically they end up crashing on land. It
is an ancient occurrence of pilot whales to strand on beaches.

The last, but not least is the theory of the earth's magnetic pull and the
possible affect it may have in certain geographic areas on their ability to
navigate.  Whales have a mineral in their heads called magnetite which
might confuse their abilities to navigate when near land masses that can
react to this mineral.

I would recommend contacting the Marine Mammal Stranding Center, at this
web address: http://www.mmsc.org.   Another link to try is
:http://key.cyberg8t.com:80/mllewel/pilot.html.  WhaleNet is also a great
reference site - you can learn to use this system at
http://whale.wheelock.edu/howtofind.html

SHORT-FINNED PILOT WHALE

Most scientific work on pilot whales has been done with the long-finned
pilot whale in the cold North Atlantic. The closely related short-finned
pilot whale lives in warmer waters and is probably the species you are
referring to.  Studies of this species of pilot whale found that they move
through areas with a water depth of about 1,000 metres. These whales seemed
to feed mainly at night, when squid come up from the depths. Typical group
size is 10 to 30, although a few pods are as large as 60.  Some individuals
stay together in core groups of five or six; others move between groups and
subgroups.  Like orcas, pilot whales live long lives - up to 65 years for
females.


Scientific name:  Globicephala macrorhynchus
Size: Males 4.5 to 5 m (max 5.5 m), 2,500 kg. Females 3.3 to 3.6 m (max 5
m), 1,300 kg
Calves at birth: 140 cm
Teeth: 7 to 9 peglike teeth on each side of upper and lower jaws
Food: Squid and various fish
Habitat: Mainly deep offshore waters
Range: Tropical and warm temperate world ocean
Status: Population unknown, but common within its range




Kim Marshall-Tilas
Whale Conservation Institute/Ocean Alliance
191 Weston Road
Lincoln, MA  01773
(781) 259-0423
fax: 259-0288
website: http://www.oceanalliance.org