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Wednesday, 24 July 2013

Oooooh, you little NUDI!!!

Diving in Cyprus, we are fighting the long fight against the over fishing which is endemic in this region.

We can dive on a Saturday and see lots of various fish life in abundance all around the coast line and come back on a Monday to find all life has been decimated. It is a terrible shame, as the fishlife does not take long to replenish and if it could just be left to give the fish a chance to grow to maturity, we could start taking on the more established Diving destinations.

Diving in Cyprus you often see nudibranchsHowever, in the midst of all this, there is one sea creature, which never fails to be seen on a Dive in Cyprus. More abundant in the winter months when the waters are cooler but ever present in the deeper waters under the thermocline in the Summer, I am, of course, talking about the beautiful Nudibranchs.

Nudi's (as we like to call them) are a group of soft bodied, gastropod mollusks. Unlike others of this kind such as; whelks, conches and periwinkles, the nudi sheds it's shell after the larval stage.

The word nudibranch comes from a mixture of Greek and Latin meaning "Naked Gills" and they can be distinguished by their striking forms and exquisite colours.

Found everywhere around the world and in every ocean and sea, the number of species of nudi that have been described is around 3,000 and new ones are being identified almost daily!! They are most commonly divided into 2 types.




1. Dorid Nudi

Dorid's have the Branchial Plume that forms a cluster on the posterior of the nudi's body.

Aeolid nudibranchs have cerata over their bodies



2. Aeolid Nudi

Aeolid's have Cerata instead of the Branchial Plume. Cerata are dorsal and lateral outgrowths on the upper surfaces of the body.







Here in Cyprus, the most commonly seen Nudibranchs are Aeolids. "Flabellina Affinis" (purple nudi) and the "Coryphella Pedata" (white tipped nudi) both have Purple bodies but while the purple nudi is entirely purple, the white tipped has (yes, you guessed it) white tips on their cerata!

These nudi's have simple eyes that can only really discern changes in light and dark. Instead , they
have sensitive antennae like protrusions called Rhinopores on top of their heads for detecting taste, smell and prey.

They may be small but all nudibranchs are Caniverous animals. They feed off sponges, hydroids, other sea slugs and their eggs and some nudi's are Cannibals, preying on their own species!! Not so cute now are they?

It is believed that the nudibranch's derive their colour from the food that they eat. Some camouflage into their surroundings while others have bright colours that stand out with vibrance which acts as a deterrent to predators. As a general rule, we are all taught, "the brighter and more colourful it is, the more dangeous it usually will be".Some nudibancs can even retain the poison from their prey to secrete as a defence mechanism against predators.

However, even with all these defences, the lifespan of the average nudi in the wild is only up to a year!

 
We used to see many different varieties of nudi here in Cyprus including the Tri colour Doris or the elegant slug but these are becoming fewer and harder to find around the Island, so let's appreciate the ones we have while they are here!!

I for one, am a big fan of the little nudi.