Subject: Data Seal Summary "Kiwi" (fwd)

mike williamson (williams@www1.wheelock.edu)
Mon, 25 Aug 1997 10:45:23 -0400 (EDT)

Subject: "Kiwi"

Hello All,

As you know we stopped receiving transmissions from both "Kiwi" and "Balti".
The last transmission from "Kiwi" was a little over three weeks ago and the
last message from "Balti" was a little more than two weeks ago.  We've been
analyzing the dive data to determine what may have happened.  We've looked
at "Kiwi" first and will send another message about "Balti" later.

When we lose transmission from a tag, there are three basic possibilities:
that the tag malfunctioned or failed, the attachment failed and the tag fell
off, or something happened to the seal.  We generally try to eliminate as
many of the possibilities as we can and see if the behavioral data can give
us any clues.  However, even with these clues,  we will probably never know
exactly what happened.

Initially,  we received dive data that showed many short and shallow dives.
For the first week it appeared she was spending most of her time at or near
the surface.   We have seen this pattern in other seals immediately after
release, and we think it may be the seals orienting to their new
surroundings.  If this pattern had continued, it may have meant that she was
not feeding and would have been cause for concern.  During the last weeks of
July, however, her diving became more regular with fewer dives overall and
more long and deep dives.  This, we thought, looked like a good pattern
resembling what we have seen in other seals when they search for food.  On
August 1, however, her behavior changed abruptly with many short, shallow
dives and almost no dives to significant depths.  We received our last
signals from the tag on August 3.

Although her movement south put her far out of her normal range, we really
cannot say  for certain that this was a bad sign.  We know stranded hooded
seals are found in these locations and even farther south.  The question of
whether a seal can survive this far south, or if they can find their way
north is the very reason we tag them after they are released.  From both of
the hooded seals we have tracked we know that they rarely,  if ever,  will
come near to shore once they are released, ("Kiwi" was probably never closer
than 100 miles from shore since she was released) so there is little chance
that we will learn anything about their lives once they are released without
tracking.

We have to remember that one of our reasons for tracking rehabilitated
animals is to learn how and if they can successfully return to their lives
in the wild.  All rescued animals would have died without our assistance,
and at best, our help gives them a second chance to resume their lives as
before we intervened.  Although we would like for all of our animals to
survive, the reality is that the wild is not an easy place for young seals
to make a living.  Studies of some populations have shown that in some years
more than one-quarter of the seals born do not survive their first year.  If
the rehabilitated seals we return to the ocean are as able to survive as
their wild counterparts, this would mean that as many as one in four would
not make it.  What  we learn from our tracking studies will help us improve
the odds for those rescued seals still in our care.  While "Kiwi" may not
have survived she was given a second chance and we have been fortunate to
have learned from it.  

Regards,

ge
############################################################################
############
                                               
DEPTH			4-52m	52-100m	100-200m	200-300m	300-400m	>400m	TOTAL

7/9-7/19...DIVES:		98	10	14	7	0	0	129
			75.97%	7.75%	10.85%	5.43%	0.00%	0.00%		
7/20-7/29			90	166	1	30	69	0	356
			25.28%	46.63%	0.28%	8.43%	19.38%	0.00%		
7/30-8/3			503	75	14	20	18	0	630
			79.84%	11.90%	2.22%	3.17%	2.86%	0.00%
=============================================================================	
8/1-8/3			478	40	4	9	1	0	532
			89.85%	7.52%	0.75%	1.69%	0.19%	0.00%
=============================================================================	
TOTAL			693	251	60	57	87	0	1148
			60.37%	21.86%	5.23%	4.97%	7.58%	0
############################################################################
############	




Greg Early
Edgerton Research Laboratory				
New England Aquarium
Central Wharf
Boston, Mass 02110
617-973-5246 (phone)
617-723-6207 (FAX)		
gearly@neaq.org