Barnacle-Eating Dorid (Onchidoris bilamellata)

Description: Barnacle-eating dorids are an off-white to gray color with splotches of various shades of brown. There are also occasionally individuals that are all white. Instead of a single ring of gills like most dorids, this species has two connected half rings. Individuals can get up to 3 cm long.

Habitat: They range from Alaska to Baja California, Mexico and can even be found in the Arctic ocean and North Atlantic ocean. They are found on rocks with barnacles ranging from the mid intertidal zone to subtidal depths of 30 m.

Diet: As their name suggests, these barnacles feed primarily on barnacles. Juveniles, however, tend to feed more on encrusting bryozoans.

Tide Pool Tidbits:

• This species is most easily identified by the double ring of gills on their back end!

• When disturbed, the barnacle-eating dorid secretes an acid from its mantle.

References: Walla Walla University, The New Beachcomber’s Guide to the Pacific Northwest by J Duane Sept, The Marine Life Information Network