Translucent Tunicate and Sea Cucumber

We saw two translucent animals on last few dives around the Pacific Remote Islands Marine National Monument: a tunicate and sea cucumber! The first mysterious marine invertebrate is called a tunicate from the Culeolus genus. These sessile organisms and their shallow-water relatives are commonly called “sea squirts” due to their tendency to expel or "squirt" out water when removed from the water. Part of the Phylum Chordata, believe it or not, this ascidian is more closely related to humans than any other of our common seafloor sightings. Tunicates have a tough carbohydrate body tunic that surrounds their water-pumping siphons and other organs. Listen to our Corps of Exploration wonder at this extraterrestrial-looking underwater animal and the associated biodiversity living alongside it. Our second translucent creature was a floating sea cucumber of the class Holothuroidae. Lit up by ROV Hercules' cameras, the details of the animal's mouth, gut, and tentacles can be clearly seen. Awesome!

Learn more about this expedition in and around Pacific Remote Islands Marine National Monument funded by NOAA Ocean Exploration via the Ocean Exploration Cooperative Institute.