Sea Slugs (nudibranchs)

clown nudibranch

Scientific name:Triopha catalinae

Family: Polyceridae

Phylum: Mollusca

Typical size: Up to 15 centimeters

Depth range: Up to 35 meters

Description: Has a long oval, dorid-shaped white body that is covered in orange spots (papillae) and orange rhinophores. Orange papillae gather on the dorsal oral flap above the nudibranch’s mouth. Its gill plume (middle of dorsal side) is also tipped with orange and is not retractable like other dorids.

Habitat and behavior: Generally found in rocky areas or kelp beds, feeding on hydroids, sponges, and other nudibranchs. It lays a thick (1 centimeter) ribbon of lightly colored eggs in a spiral pattern.

Cockerell’s dorid

Scientific name: Laila cockerelli

Family: Polyceroidea

Phylum: Mollusca

Typical size: 0.75 to 1 inch long

Depth range: 0 to 35 meters

Description: They have a white/translucent body and cerata have bulb-like orange/red tips. Body is oblong and rhinophores are short and deep orange/red. 

Habitat and behavior: They live from southern Alaska to northern Mexico. They live in rocky areas and eat bryozoans.

false sea lemon

Scientific name: Doris montereyensis

Family: Archidorididae 

Phylum: Mollusca

Typical size: Up to 15 centimeters

Depth range: Up to 50 meters

Description: Round, dorid-shaped body with gills on end of back. Can range in color from white to yellow to orange. Has darker yellow colored rhinophores and gills with light colored tubercles (bumps) and black spots covering its back. Can be differentiated from the true sea lemon because this species has black dots that will be apparent on the tubercles, while the true sea lemon has black dots that do not extend onto tubercles. The true sea lemon also has lighter-colored branchial gills, where the false sea lemon’s are darker than or the same color as the body.

Habitat and behavior: Can be found in rocky areas and pilings and feeds on species of sponges. Eggs are formed in a thick (2 centimeters), ribbon-like rose pattern that is light in color and attached to a hard substrate.

Golden Dirona

Scientific name: Dirona pellucida

Family: Dironidae

Phylum: Mollusca

Typical size: 7 to 12 centimeters long

Depth range: Intertidal to 40 meters 

Description: A nudibranch with bright orange-red color with white tips on the cerata (spike like structures on its back). 

Habitat and behavior: They can live from Alaska to the Puget sound, across the Bering sea to Japan, Korea and Russia. They can live in tide pools, where they search for food. They eat bryozoans and will sometimes eat hydroids and ascidia. 

hudson dorid

Scientific name: Acanthodoris hudsoni

Family: Onchidorididae

Phylum: Mollusca

Typical size: Up to 2 centimeters

Depth range: Intertidal to 25 meters

Description: Translucent white colored body with bright yellow papillae and a bright yellow margin. The branchial plumes have bright yellow tips and rhinophores are yellow or white with lamellae. Very similar looking to the yellow-edged cadlina except for this species has the yellow branchial plumes and rhinophores.

Habitat and behavior: Feeds on bryozoans which is unique for dorids. 

leopard dorid

Scientific name: Diaulula sandiegensis

Family: Discodoridae

Phylum: Mollusca

Typical size: Up to 8 centimeters

Depth range: up to 35 meters

Description:  Body is a cream or grey color with matching branchial plumes and rhinophores. Dorsum has a varying number of large, dark brown rings or splotches. Very small tubercles.

Habitat and behavior: Eats sponges. Narrow ribbon of eggs.

nanaimo dorid

Scientific name: Acanthodoris nanaimoensis

Family: Onchidorididae

Phylum: Mollusca 

Typical size: Up to 4 centimeters

Depth range: Intertidal to 25 meters

Description: Translucent white colored body with yellow papillae covering the dorsum and a yellow margin. Very similar to the hudson dorid, except the branchial plume has red tips and the rhinophores are also red with lamellae. This species also has a dark grey phase.

Habitat and behavior: Inhabits rocky areas or artificial reefs. It lays its eggs on rocks in a characteristic spiral, but the nanaimo dorid’s eggs look foamy and are cream colored. 

northern opalescent nudibranch

Scientific name: Hermissenda crassicornis

Family: Facelinidae

Phylum: Mollusca 

Typical size: 50 millimeters to 5 centimeters

Depth range: Intertidal to 35 meters

Description: Long oval shaped body with fur like respiratory projections coming off its body that are white and orange in color with a white band at each tip. It’s rhinophores are horn-like and between them is an orange line surrounded by two light blue/white lines that run down it’s back.

Habitat and behavior: Can be found in mudflats, eelgrass beds, and rocky areas. Individuals may fight each other, and the winner sometimes will eat the other. They also feed on sea anemones or hydroids. H. crassicornis is the biggest predator to the sea pen, Ptilosarcus gurneyi. Their eggs are commonly found on strands of eelgrass and appear as small, oblong-shaped capsules linked together in a clump or ribbon.

Red Flabellina

Scientific name: Predaceous aeolis

Family: Flabellinidae

Phylum: Mollusca

Typical size: 2 to 5 centimeters

Depth range: 70 meters

Description: A member of the nudibranch family, they have a translucent body and light red to brownish gills with white tips.

Habitat and behavior: Tend to stay in subtidal areas, and live on or near the sea floor.

sea lemon

Scientific name: Peltodoris nobilis

Family: Discodoridae

Phylum: Mollusca

Typical size: Up to 30 centimeters

Depth range: Low intertidal to 35 meters

Description: Round, large body that ranges in color from pale yellow to dark orange. Branchial plumes have white tips, one distinguishing factor from the false sea lemon. Like the false sea lemon, the true sea lemon has brown and black dots on the dorsum but for the true sea lemon these markings do not extend on to the tubercles. Therefore, the tubercles are yellow in color and so are the rhinophores.

Habitat and behavior: Found in sandy areas and on hard substrates like artificial reefs. Eggs are laid in the thick ribbon spiral and yellow in color. Supposedly this species gets its name from the citrus smell that is evident when handled.

shaggy mouse nudibranch

Scientific name: Aeolidia loui

Family: Aeolidiidae

Phylum: Mollusca

Typical size: 3 to 10 centimeters

Depth range: Intertidal to 300 meters

Description: Can be identified by many cylindrical cerata covering its body like a carpet except for a triangular area that is bare from the rhinophores to the mid dorsum. Brown/grey in color and cerata are covered in grey or brown spots. Bumpy rhinophores without lamellae.

Habitat and behavior: Often found on rocks or any kind of structure such as docks or boats. Sometimes takes the colors of the anemone that it’s eating. The Shaggy Mouse Nudibranch may be tiny but it is a voracious predator. It eats enough anemone tissue to equal half or all of its body weight in a day, mostly from green anemones, plumose anemones, or sometimes painted anemones.

southern opalescent nudibranch

Scientific name:Hermissenda opalescens

Family: Facelinidae

Phylum: Mollusca

Typical size: 1 to 4 centimeters

Depth range: Up to 35 meters

Description: Similar to the northern opalescent, it has a long oval shaped body with fur like respiratory projections coming off its body that are white and orange in color but it does not have a white band at each tip as the northern opalescent does. It’s rhinophores are horn-like and between them is an orange line surrounded by two light blue/white lines that run down it’s back.

Habitat and behavior: Can be found in mudflats, eelgrass beds, and rocky areas. Will sometimes feed on other nudibranchs or even other small Northern opalescents, and sea anemones or hydroids.

Tuburculate Dorid

Description coming soon!

white berthella

Scientific name: Berthella chacei

Family: Pleurobrachidae 

Phylum: Mollusca

Typical size: 2.5 millimeters to 5 centimeters

Depth range: 0 to 20 meters

Description: A sea slug, but not a nudibranch. Unlike dorid nudibranchs, B. chacei does not have a branchial plume on its back. Instead, it has a gill underneath the right side of the mantle. B. chacei is a translucent white color with opaque white spots, a highlighted margin, or perimeter around its round body. It has two tube-like rhinophores without lamellae.

Habitat and behavior: Usually can be found beneath or on rocks or in crevices, using its foot to travel and feed on ascidians and sponges.

white lined dirona

Scientific name: Dirona albolineata

Family: Arminidea

Phylum: Mollusca

Typical size: 1 to 18 centimeters

Depth range: Up to 37 meters

Description: Has an oval shaped translucent body with extruding flat and pointed cerata that have white tips. Sometimes the cerata can be peach or yellow colored. 

Habitat and behavior: Can generally be found in eelgrass beds or other algae. They feed on a variety of things such as snails, hydroids, and crustaceans. Their egg ribbons look like ramen noodles, found on eelgrass or other algaes or close to a food source. 

yellow edged cadlina

Scientific name: Cadlina luteomarginata

Family: Cadlinidae

Phylum: Mollusca

Typical size: 2 to 4 centimeters

Depth range: Up to 45 meters

Description: Translucent white colored body with bright yellow tubercles and a bright yellow margin. The branchial plumes and rhinophores are white with lamellae. Can be distinguished from the hudson dorid because rhinophores and branchial plumes are always white. This species also has tubercles over dorsum rather than papillae, and is also bigger than the hudson dorid.

Habitat and behavior: Can find it moving around on rocky areas with its foot feeding on species of sponges.