Armina Californica
 

By Scott Boyd

The striped nudibranch is commonly sighted partially buried on sandy, flat bottomed dive sites along Puget Sound.  It ranges from the Gulf of Alaska, all the way down to Panama, growing to a length of about 3”.  The brown-striped nudibranch feeds almost exclusively on Orange Sea Pens, and can almost always be found wherever fields of Sea Pens are located.  The brown color of the stripes lends itself to hiding in the sand very effectively during the day.  When the nudibranch comes out to prowl the bottom for food (which it finds entirely by smell as it has no eyes), sand often sticks to its back, further camouflaging it.  

This species is easily identified by the lengthwise brown and white stripes along its back with no Cerata.  Instead there are gill-like structures below a flap along its dorsum, just above its foot. The only visible projections are two blunt-shaped rhinophores extending forward from the front end of the body.  Members of this species are hermaphrodites; having both male and female reproductive organs and can often be found in mating clusters during June and October. Eggs are deposited in ribbon-like, pale yellow clusters along sandy bottoms.

Click on the photo above for a larger photo of the striped nudibranch.