Triopha catalinae (Cooper, 1863)

Common name(s): Sea clown nudibranch, Clown nudibranch, Catalina triopha

Synonyms:  Triopha carpenteri

Phylum Mollusca
Class Gastropoda
Subclass Opisthobranchia
Order Nudibranchia
Suborder Doridacea
Family Polyceridae
Triopha catalinae subtidal from off Sares Head.  A metric ruler is in the background.
(Photo by: Dave Cowles, July 1997)
Description:  As with many dorid nudibranchs, the anus of this species is found on the dorsum 1/3 to 1/4 from the posterior end, ringed by gills (see photo above).  The body is translucent white to pale yellow with deep orange spots, as well as 10-15 bright orange coronate  papillae along the lateral margins and 8-15 orange papillae around the edge of the oral veil.   The clavus of the rhinophores is brownish-orange, and the five non-retractable gills are white with orange tips.  Total length 2.5-15 cm.

How to Distinguish from Similar Species:  This nudibranch is distinctive in our area.  No other has the combination of white body scattered with orange coronate  papillae and deep orange on the tips of the gills and rhinophores.

Geographical Range: From the Aleutian Islands, Alaska to Baja California

Depth Range:  Intertidal to 35 m.

Habitat:  Rocky areas or around kelp beds.

Biology/Natural History:  This is one of the largest nudibranchs able to crawl on the underside of the surface film in tide pools.  It feeds on bryozoans such as Bugula californica by digesting the soft parts.  Tide pool fish avoid Triopha, and this is believed to be because of some sort of chemical repellant.  In Washington eggs have been observed in April and June.  The coil of eggs formed is white or cream-colored (photo).  The ribbon of eggs is attached to a solid surface by its shorter edge (photo).  The free edge is wavy and appears like a ribbon.



Dichotomous Keys:
  Carlton, 2007
  Flora and Fairbanks, 1966 (as Triopha carpenteri)
  Kozloff 1987, 1996
  Smith and Carlton, 1975 (as Triopha carpenteri)

General References:
  Behrens, 1991
  Harbo, 1999
  Johnson and Snook, 1955 (as Triopha carpenteri)
  Kozloff, 1993
  Morris, et. al., 1980
  Sept, 1999

Scientific Articles:

Web sites:

General Notes and Observations:  Locations, abundances, unusual behaviors:

This nudibranch is usually one of the most commonly found subtidally along Sares Head and Northwest Island.

Two individuals mating (they are hermaphroditic).  This species mates very readily in aquaria if given half a chance.  Photo by Dave Cowles, July 2000

This individual is laying a string of eggs.  View from below.  Photo by Dave Cowles, 2-2004

An underwater photo by Kirt Onthank, June 2007

Crawling on water surface tension
Although this species can get quite large (the specimen pictured here is 8 cm long), it can still crawl upside-down clinging to the surface film of the water, as this individual is doing. The view is from above but since the animal is upside-down with its foot clinging to the surface film, the foot is uppermost. Photo by Dave Cowles, July 2017

Authors and Editors of Page:
Dave Cowles (2007):  Created original page.  (An earlier version was worked on by Robbie Wheeling)
CSS coding for page developed by Jonathan Cowles (2007)