We’ve got some cool new additions to our Puget Sound Fish exhibit—learn a bit about them here, then get to know them during your next visit to the Seattle Aquarium!
First of all, what’s a nudibranch? Put simply, a nudibranch is a sea mollusk without a shell. And what makes this animal a nudibranch? The name nudibranch means “naked gills,” and you can see the circular cerata (or dorsal and lateral outgrowths) on this animal’s back that it uses for gas exchange. (You can also see the darker branching digestive parts inside the cerata.)
Also in common with other nudibranchs, these critters are hermaphrodites, meaning that they have both male and female sex organs, and two animals will fertilize each other during reproduction. So look for egg ribbons in the exhibit!
What sets the hooded nudibranch apart from others of its kind? This species lacks a radula, the rasping tongue that other nudibranchs (and mollusks) use to feed. Instead, it has a spectacular oral veil, or hood, for trapping small animals and pulling them into its mouth. It feeds on copepods, amphipods and ostracods (small marine crustaceans), as well as small post-larval mollusks.
What makes this fish a sculpin? Like all sculpins, it lacks a swim bladder and so it spends most of its time perched on objects like rocks, kelp or buoy lines. Although little is known about their reproductive habits, sculpins as a group are brooding fish and it is typically the male’s responsibility to protect nests of eggs. What sets them apart from other sculpins? Their Latin name, synchirus, comes from Greek for “hands together.” The pectoral fins of the manacled sculpin come together in a round form that allows them to cling to kelp blades, piling undersides or exhibit windows. They were once thought to be rare in the wild, but have since been widely seen from Alaska to California, especially in healthy kelp forests.