Behind the researches
Smile you're being identified
Photo-identification of animals in the open sea is quite a hard task as
we want to get the maximum of details from an animal that is moving permanently,
hides under water most of the time and above all we are on a boat that
moves everywhere! Without counting on other embarrassing factors such
as shiny reflections of water, that hides the interesting details. Whales
would better dry themselves before they surface!
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The identification of this fin whale will be difficult as the fin is out framed; the shining hides the pigmentation (and the horizon is skewed). |
First of all it requires a good position: to identify a dolphin from its dorsal fin we need a perfect profile of the animal, to fix the caudal of a sperm whale on the film we have to stand behind him exactly in its axis. The distance is of course important: too far from the animal we waste the film as we get a small black dot on which no details will appear; too close and it will miss an important part of the animal essential for its recognition. The zooms (100-300) often allow to level that inconvenient.
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Cetaceans
are moving fast, spending most of their time out of our view to
emerge for a few seconds without warning of where or when. Consequently,
the photographer and his camera must have quick reactions. It's
up to the photographer to have good reflexes to shoot at the right
fraction of second and to the camera to be good enough to do the
focus (distance and opening) as fast as possible. The autofocus
with quality cells are advised to avoid countless blurred or unexposed
pictures. |
Be
careful also with the position of the sun: an unfavourable light
is sometimes aesthetic but the pigmentation is no longer visible
and the picture will lose its interest for photo-identification. |
To
make up a complete catalogue of photo-identification on a dolphin group,
pictures of the two profiles are necessary. It is never that easy when
you are in the middle of a group of animals as we are never sure to have
taken pictures of both sides of all animals, then when we sort them out
we still need to know who to match with who. Be careful also with the
angle of view (a perfect profile is recommended) and with the bending
of the back that changes the shape of the dorsal fin (photos here under).
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Photos Renaud de Stephanis
.From the form of the fin, it is not the same dolphin (bending of the back and angle of the shot are different), however the white mark at the base of it and the scars on the tip are identical therefore it is the same bottlenose dolphin. |
Digital cameras are very attractive as the photo is viewable directly: no need to wait the return to the port to develop the photos, finished with the enormous sort out of hundreds of pictures accumulated during weeks of missions, finished the breakdown of films, and the waste of missed pictures that cost the same to develop, forgotten the fastidious scanning sessions to record all the interesting shots! All the good pictures are directly downloaded and classified. The efficiency is increased as we can the same day identified animals that we did not recognise when they appeared too quickly. |
Unfortunately, these new technologies are still very expensive to get material that is adapted to this kind of work as most of the digital cameras are really too slow: for an investment of 1500 €, we have gathered blurred pictures (autofocus too slow) and empty seas (the dolphin dived by the time the camera decided to trigger the picture).Malheureusement ces nouvelles technologies sont encore très onéreuses pour obtenir du matériel qui soit adapté à ce genre de travail car la majorité des appareils numériques sont beaucoup trop lents : pour un investissement de 1500 €, nous avons collectionné les photos floues (autofocus trop lent) et les mers vides (le dauphin a replongé le temps que l'appareil se décide à déclencher).
CIRCE Newsletter n° 2 - June 2002 - made by Philippe Verborgh, Anne Collet & Jean-Michel Bompar