Saturday 17 October 2015

A Colourful Craze - the humble Nudibranch

No matter where you dive or who you dive with there will be someone, Instructor, photographer or your average diver, who will be raving about Nudibranches. What are they? Why do they have such a dedicated following? And, indeed, why are they so awesome?

Tricolor doris - Gibraltar
Felimare picta - Gibraltar

      




First, and foremost, I am a dedicated Nudibranch fanatic. Ever since being introduced to these little critters of the sea I have, on the verge of obsession, been searching for them everywhere. Taking photos of these perfect subjects is passion of mine.

Varicose Wart Slug - Thailand
Marionia blainvillea - Spain

      











Nudibranch (pronounced Nudi-brank) are quite simply slugs of the sea, but unlike their land-trapped cousins, they are anything other than bland and boring. Nudibranch come in all range of colours, forms and sizes. Some are smaller than a fingernail (especially the young) others can be the size of a fist. Estimates range up to 6000 different species of Nudibranch worldwide.

Flabellina - Spain
Pink Flabellina - Tarifa, Spain
            










Nudibranch literally means “naked gill” and you can see this feature as a flower like protrusion from which the Nudibranch actually breathes. They have been found in shallow reefs all the way down to over a mile deep. They have succeeded in colonising nearly every part of the ocean despite being brightly coloured and slow moving. Why then have they been as successful as they have been?

Doris - Spain
Tricolor doris - Spain
            










Their secret is in how they defend themselves. Having shed their shell millions of years ago, Nudibranchs have developed ways to secrete poisons and stinging cells making them a very undesireable dinner. They are also carnivores and eat coral, starfish, even each other and each time they eat, they absorb the poisons and defenses and sometimes even the colours of that which they have consumed.

Add caption
Add caption
            












Why are so many divers (myself included) so obsessed with these creatures. Firstly, despite the bright markings, they can be hard to spot so the challenge itself is rewarding. Secondly, they make relatively easy and wonderful subjects for photography, Google images is replete with thousands of photos of nudibranches. Lastly, and for me this is the best reason: they are an essential part of the ecosystem. They eat vociferously and can sometimes be the last bastion against more invasive species such as Crown of Thorns starfish.


Blue Dragon - Cambodia
Jorunna funebris - Cambodia
            












So remember, next time you're diving and somebody does the nudibranch sign (two fingers like rabbit ears), don't dismiss them, go see the nudibranch and admire its beauty, its resiliance and its importance to the ecosystems around you.

- Nic
Diving with Nic
Nudibranch Pictures

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