Nudibranchs of Hawaii

Babosa_de_mar By Diego Delso, CC BY-SA 4.0

By Gina Stewart

One of the best things about scuba diving in the beautiful waters of Kauai is being able to see the many beautiful and brightly colored nudibranchs that occupy our reefs.  Nudibranchs are marine slugs that have no hard shell.  Some of them are carnivorous hunters, while others feed on sponges and corals.

“Nudi enthusiasts” know that the best diving in Kauai waters are ones where each dive becomes a treasure hunt,  where divers eagerly seek out these brightly colored sea slugs.   On an easy shore dive at the Koloa Landing dive site, we often see the gorgeous orange, red and white Kangaroo Nudibranch.   This creature feeds primarily on sponges, and ingests the toxins produced by that sponge to be used for its own defense against predators.  Recently a rare Fellows nudibranch was spotted at one of our west Kauai scuba diving sites.  This nudi has a stark white body with dark black gills and rhinosphores.  This nudibranch is endemic to Hawaii, meaning, it can only be found in Hawaiian waters.

Spanish dancer by Peter Southwood, CC BY-SA 3.0

The Spanish Dancer is another spectacularly beautiful nudibranch that is thought to be endemic, and just happens to be the favorite of Fathom Five owner Jeannette Auber.  They can grow up to 8inches long, and are a bright orange red color.  To spot one on the reef is very special indeed, but to spot one free floating in the water column is truly an extraordinary site to behold, as this nudi swims by flexing its body back and forth, swirling its mantle like the skirt of a Spanish dancer (thus the name!).    You can go to @fathomfivedivers on Instagram and find the video of a Spanish Dancer in the water column from resident photographer @shaundoylephoto.

Kauai scuba diving sites are home to many of these mesmerizing invertebrates.  Whether you prefer a shore dive at the Koloa Landing dive site, or a charter on one of their well appointed boats, Fathom Five Divers is poised to deliver some of the best diving in Kauai where you will often see some of our resident nudibranchs.

More information on nudibranchs and other marine invertebrates can be found in the well known book by John Hoover on the subject,  Hawaii’s Sea Creatures: a Guide to Hawaii’s Marine Invertebrates.  This book is also conveniently sold at the dive shop, so you can pick up a copy when you stop by to book a dive to see these beautiful nudibranchs with your own eyes.

Contact us today to experience some of these beautiful sea creatures for yourself