By guest blogger Beth Alexander
Ever since I first discovered nudibranchs during my dive course in Fiji, I have become obsessed with them — and I’m not alone. Many divers cite these tiny treasures as one of the highlights of a dive. The endless number of species is mind-blowing; with so many different sizes, shapes and colors, I wonder how I ever just swam over these beautiful creatures without even seeing them.
Nudibranchs, known scientifically as Nudibranchia, are a group of soft-bodied, shell-less marine gastropod mollusks. The name Nudibranchia itself comes from the Latin nudus, meaning ‘naked,’ and Greek brankhia meaning ‘gills.’ Nudibranchs can be incredibly diverse, from thick to thin, flat, long, short, brightly colored or plain to suit their surroundings. With some of the most fascinating and striking patterns of any creature on earth they deserve to be recognized and identified on a dive.
Nudis are carnivorous, and graze on algae, sponges, anemones, corals, barnacles, and even other nudibranchs. It is from this food that they derive their coloring.
With sizes ranging from 12 inches to less than ¼ inch (31cm to 6mm), it’s no wonder most divers fail to spot these elaborate creatures (myself included). They can be found throughout the world’s oceans, but are most abundant in shallower, tropical waters, with their favorite habitat being coral reefs.
One of the nudi’s most interesting characteristics is its hermaphroditism, meaning that it has both sets of reproductive organs, so can therefore not be singly classed as male or female of the species.
A great nudibranch identification reference book called Nudibranchs Encyclopaedia, by Neville Coleman, has photographs and reference information on each species discovered so far. There’s is also a Facebook site called Nudibase – sharing Nudibranch knowledge, where in members can share information and photographs of unknown nudibranchs and others can help identify them.
Although there are currently more than 3,000 known species, new ones are being identified almost daily. I hope next time you’re out on a dive you take the opportunity to try and spot some of these marvelous and fascinating creatures and who knows — perhaps you too could have one named after you.