Subject: whales

Greg Early (gearly@neaq.org)
Fri, 12 Nov 1999 13:13:07 -0500

At 02:09 PM 11/10/99 -0500, you wrote:
>Greg, 
>
>Thank you very much for your quick response.  Below are some more
>questions for you from the other half of the fifth grade.  
>
>From all of us:  We started tracking the two pilot whales that were
>recently released off of Long Island and we all want to know a little more
>about how the radio tag works.  How many times does the satellite travel
>around the earth in one day? 

This is a little complicated.  Right now there are three satellites used in
this type of tracking.  They fly in orbits that take them over both the
north and south poles each orbit.  Therefore, while they are going around
the earth, the earth is rotating under the satellites.  What this means is
that the satellites will be over the same locations at the same time each
day (roughly).  It takes the satellites 102 minutes to make each trip
around.  The catch (and if you look at a globe you can see how this works)
is that if you are at the poles the satellite will spend more time
overhead, than if you are at the equator.  (the difference is a little over
six hours at the pole and a little over an hour at the equator).  A
satellite will pass overhead about once every 15 minutes in the location
the whales are.

 How were the tags attached to the whales? 

The tags are attached surgically by mounting small nylon bolts through the
edge of the whales dorsal fins.  Sounds gross, but it is about like having
your ears pierced.


>How long do the batteries usually last?

It depends on how many times the transmitter sends signals.  This can be
controlled by the people that program the tag (so the tag will only send so
many signals per day, and skip days of transmission to save power).  It is
also, to some extent up to the whale, because the transmitter will only
signal when the whale is at the surface, and the tag is out of the water.
So if the whale is spending a lot of time under the water, it will send
fewer signals.

I think they are hoping these tags will signal for about three months or so.
>
>From Emily At.,  Maddie D., Will and Amy:  What are some of the natural
>causes that whales die from?

We know that whales can become sick due to parasites.  Some large whales
(fin and humpback whales and others) have been known to get a parasitic
worm that damages their kidneys, as one example).  We also think whales can
get infectious diseases as well.  A pilot whale was found to have a type of
virus (influenza), that is similar, but not the same as the virus that can
cause flu in people.  Scientists have also found another virus (distemper)(
a virus related to but not the same virus that can cause measles in people)
that looks like it can cause disease in dolphins and maybe whales.  Whales
can also be poisoned if they eat food that has concentrated naturally
occurring toxins.  In one case, scientists think humpback whales became
sick and some died from eating fish that had picked up a toxin from an
algae that was passed up the food web. (the same toxin that can cause
parasitic shellfish poisonings in people).  The picture of me on the
WhaleNet website was taken while I was examining one of the whales that we
think was poisoned by this toxin.
>
>From George H. and Dan N.:  Can whales have twins or triplets? 

No...  As far as we know whales do not have twins or triplets.  It is even
very rare that seal or sea lions have multiple births.   What is
>your favorite species of whale and why?  While working at the Aquarium I
knew a couple of bottlenosed dolphins that I liked as individuals.  I still
think sperm whales are the neatest whales (mostly because they are big,
deep diving, and I grew up near New Bedford, where a hundred or so years
ago, they used to hunt sperm whales.  (My favorite marie mammals however
are hooded seals.)
>
>From Zach and Hilary:  What is the most common disease that whales get?  

Look at the answer above for some ideas.  I suspect that whales get
diseases that we have not been able to  understand, because we only see a
small portion of the sick whales that are out there.  The most common
disease that is diagnosed in whales that come ashore is pneumonia (lung
infections).  But this is only the condition that we recognize the most
often.  It is probably not the most common disease that whales get.  I
think this means I do not know....
>
>From Lily and Andrew:  What is the largest number of strandings that have
>occured in one year?

Depends on where you are talking about (and what species).  In New England
we may have about 150-200 strandings of whales dolphins and seals per year.
 Most of the strandings are seals.  In some years we have had mass
strandings of dolphins or whales, sometimes nearly one hundred at a time.
One of the largest strandings on the east coast happened in 1884 when about
2,000 pilot whales stranded on Cape Cod.  On the west coast there are not
as many whale strandings, but during El Ninjo there is a huge increase in
the number of young sea lions and seals that strand.
>
>From Thomas and Catherine:  Why have you been at the NE Aquarium so long? 

Hmmm good question.  I ask myself that one every once and a while.  The
main reason is that there is always something new going on, so in a way it
is not always the same job...

>Is there something in particular that keeps you there?  
>
(ps during my time here, I have been chased by sharks, kissed by sea lions
and worked with folks that have returned hundreds of animals back to sea,
that would have otherwise died...it's hard to beat that)


>Thank you Greg, 

Your Welcome
>
>Sue Shirley
>Dedham Country Day School 
>
>
>
Greg Early
Edgerton Research Laboratory				
New England Aquarium
Central Wharf
Boston, Mass 02110
617-973-5246 (phone)
617-723-6207 (FAX)		
gearly@neaq.org