Swimming Nudibranch

Nudibranchs are the marine equivalent of a garden slug. However, unlike terrestrial slugs, nudibranchs can often be quite colorful and attractive. The largest of the Hawaiian nudibranchs is the Spanish dancer (Hexabranchus sanguineus) which can sometimes achieve a length of over one foot.

While most nudibranchs crawl across the substrate, the Spanish dancer, when alarmed, can swim through the water column by flexing and extending its body in an undulating fashion. In doing so, its extended mantle waves rhythmically much like a flamenco dancer's skirt!

Spanish Dancer

Photo Copyright 2010 by Barry Fackler

Photo Copyright 2010 by Barry Fackler

For all my years of diving in Kona, I've never seen a Spanish Dancer nudibranch. I don't night dive very often and that's when they're most active. My luck changed, however, on an early morning dive earlier this month when I happened across a juvenile specimen in a small cave at Honaunau.

Photo Copyright 2010 by Barry Fackler

This was a small individual, only a couple inches in length, but very active. It was making its way to the back of the cave to escape the increasing sunlight.

Photo Copyright 2010 by Barry Fackler

This little creature allowed me plenty of time to take its photograph and I was happy with the images I got. In the past, this small cave has been the scene for encounters with sea turtles, ulua, a Whitetip Reef Shark and an assortment of interesting mollusks and crustaceans. It's a good place to check out.

Photo Copyright 2010 by Barry Fackler