Well, remember that Aphrodite's transponder was completely stationary on the
map for several days before the signal cut out.
It seems likely to me that the positions on the map are those last recorded
by the system. Also these transponders are very accurate, meaning we can
see Styx clearly waddling about on Mewstone Island. This would suggest that
if a transponder doesn't move at all it's probably not transmitting.
Therefore outcomes would be one of two types: one where the transponder
fails immediately, resulting in no apparent movement, or that it drifts
about aimlessly but only metres per day rather than kilometres.
If Aphrodite had been hooked on a long line we would have seen the carcass
drifting at (or close to) the surface, or at least it would have been
retrieved by fishers at one stage and then, I guess, tossed overboard. This
would have been shown as some drifting on the map. If transponder detatched
somehow the effect would have been the same. (This is assuming that a
drowned albatross' transponder is capable of sending a signal through
several metres of water, but I do hear from a diving friend that you can use
GPS under water. Technicalities of this are beyond me, but have things to
do with signal strength, etc.)
If, alternatively, she were taken live by a shark while on the surface,
either resting or dead having been hit with a hailstone, etc, the signal
would probably have disappeared when the shark dived (or chewed?).
Therefore this is the more likely outcome.
Can people comment on my logic?
-----Original Message-----
From:
On Behalf Of Peter Milburn
Sent: Friday, 21 May 2004 10:58 AM
To:
Subject: Albatross race update
>Graham Turner wrote
--------------------------------------------
Birding-Aus is now on the Web at
www.birding-aus.org
--------------------------------------------
To unsubscribe from this mailing list, send the message 'unsubscribe
birding-aus' (no quotes, no Subject line)
to
|
