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So here are some fantastic photos by Andrew Brown, who was in Bilene over the festive season, have a look at them on his blog

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Mantis Shrimps

Funny thing about perception. When you don't expect something, you often don't see it. For me, one of the interests of diving is to discover creatures I didn't know before. I often poke into holes, turn over rocks to see what's crawling under them and generally become a nuisance to crawly critters under water...

A while back, I noticed a creature I hadn't seen before. It inhabited a perfectly round hole on the crumbly bottom at the foot of the cliff at the mouth of the lagoon. The hole was so perfectly round that I suspected the animal had carved it. It was about three to five centimeters diameter, and the animal occupied the opening completely. As I approached, it retreated inside the hole, but soon came back. Good. I like curious animals, they're fun to play with...

It took me quite a while to identify what I'd seen on the snorkeling outing that day, especially since the only part of that critter I'd seen was a pair of eyes, and the front of the head, or rather what I thought were eyes and head.

After much browsing of "Two Oceans", the excellent book by George and Margo Branch, and some searches on the Internet, I finally settled on a Mantis Shrimp.

The article on Wikipedia about Mantis Shimps, in particular, is very informative for a neophyte like me. A short extract about their eyesight might convince you to pay more attention to these creatures: 

The eyes of mantis shrimp may enable them to recognize different types of coral, prey species (which are often transparent or semi-transparent), or predators, such as barracuda, which have shimmering scales. Alternatively, the manner in which mantis shrimp hunt (very rapid movements of the claws) may require very accurate ranging information, which would require accurate depth perception.

The fact that those with the most advanced vision also are the species with the most colourful bodies suggests the evolution of colour vision has taken the same direction as the peacock's tail.

I have since visited the Mantis Shrimp very regularly at the mouth, Despite searching quite thoroughly, I haven't found another specimen. I have managed to coax it half-way out of its burrow, but not fully out. It has very interesting black and yellow patterns on its carapace and body, but I could not get a good picture because both my hands were occupied trying to make it come out of its hole.

Then, on a dive, I spotted a more colourful one:

Since then, I've been able to spot more and more on the dives.

The fact that they seem to stay in the same place most of the time makes it easy to find them again and again.

One more reason to dive in Bilene...

Dive safely, don't hold your breath!

Daniel                       :-)

<Added a few days later>... a video of one of the encounters. 

I think this is a Lysiosquillina maculata, the zebra mantis shrimp or striped mantis shrimp (see Wikipedia)

A lot more photos on my G+ albums.
A very interesting article in Practical Fishkeeping.