The evolution of tracking mighty great white sharks

Eve - the largest great white tagged in Gansbaai

I was thinking about why I chose my dogs’ names. Why do certain people use human names and then others opt for really dog-related names?

Then my thoughts went to car naming, I mean, I have named all my cars and there has been a few over the years.

But Sharks? How do we know, it is really the same one?

Here is one of the answers:

Photographic identification


Sharks have become well studied over the last few decades although I must add there is still so much more to find out. Our marine gurus spend so much time at sea in aid of research. At the point of encounter with this predator, it is tagged, the DNA is sampled and the dorsal fin identified and documented.

You might think that tagging is unnecessary, why not just photograph the dorsal fin? It is not effective on its own. Firstly the shark does not pose and the waters are not still. So to get the perfect photo is exceptionally difficult. It has to be straight on.

The photo can be perfect but the water droplets on the lens and shark could hide important information, which researchers find essential with identification.

Researches used the same technology which is used for facial recognition and of course this won’t be very accurate.

Michael Rutzen, one of my all-time Gansbaai legends teamed up with Dr Andreotti. Together, they created a bar code identification system.

This system simply requires three different sides of the dorsal fin to be documented. All three different sides of the dorsal fin need to be photographed and if one does not match up but the other two do, well you have a better chance to identify the shark than not doing this.

Of course, we have a Shark database and these mugshots are all available there. The tagging allows seeing where the shark has been amongst other things and the DNA can then without a doubt confirm that this is indeed the same shark.

My favourite Lady has been Eve, the largest female Great White to be tagged in Gansbaai

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