This small, soft-bodied dorid sea slug is only found in the main Hawaiian Islands, and was first discovered in 1982.
It lives in dark caves under the big waves in depths from about 15 to 100 feet. You have to scuba dive back into the dark lava tubes and caves and use a bright light to find one of these colorful nudibranchs, so back in old Hawai‘i no one even knew they existed. The dark caves under the Hawaiian waves are just filled with all kinds of stunning-looking creatures that never see sunshine.
The gold lace nudibranch is about 2 inches long and has a clear body covered with beautiful gold lace. They are called “nudibranchs” because they have ” nude gills.” Their soft, feathery gills are on top of their body, and are speckled black and white. They also have two black-and-white rhinophores, which are sensory organs. The nudibranchs crawl slowly over the surface of the caves, feeding on sponges, hydroids and certain types of cave corals. Most Hawaiian nudibranchs are poisonous to eat, and they do not have any known predators. They don’t produce toxins like some fish do, but they recycle the toxins found in the sponges they eat and keep the toxins in their body for protection.
Because these colorful nudibranchs are so hard to find, they are not well-studied. They seem to only live for about a year, and they don’t do well in aquariums. DNA test show they are hermaphrodites having both male and female sex organs, and they do mate with each other and lay eggs that are deposited in a coiled ribbon they stick to cave walls. The egg ribbons look like small flowers growing in the dark cave, and they can be quite colorful.
Recent studies have shown once the eggs hatch the new baby nudibranchs can swim, and they have tiny shells for protection.
They float around with the plankton until deciding to settle on the reef. Once they find a good home and crawl into a dark cave they lose their shell and start feeding on poisonous sponges.
You can see many of the Hawaiian nudibranchs in action in my marine-life school-education movie series on my YouTube channel at Underwater2web, in my new movies about marine life at Shark’s Cove on O‘ahu and Koloa Landing on Kaua‘i. I also have a nudibranch-identification link up on my web page at Underwater2web.com.
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Terry Lilley is a marine biologist living in Hanalei. He is co-founder of Reef Guardians Hawai‘i, a nonprofit on a mission to provide education and resources to protect the coral reef. To donate to Reef Guardians Hawai‘i go to www.reefguardianshawaii.org.
