Spiral Bryozoan

Authors:  Eden Murray and Claire Troost

Scientific Name:  Bugula californica

Other Common Names:  Stiff Stalk Bryozoan, California Moss Animal, Pacific Branching Bryozo

Bugula californica can grow up to 7.5 cm tall and ranges from BC to Hawaii and the Galapagos Islands. It lives in subtidal zones as deep as 400m. It is commonly attached to hard surfaces, including docks and rocks. Each colony of the bryozoan is shaped similar to an evergreen tree, and is coloured light brown. It reproduces sexually, and after fertilization will form a planktonic larvae that settles in the subtidal zone. It grows through budding or cloning, to grow in a spiral pattern off the main axis. It is a main food source of the Clown Nudibranch (Triopha catalinae), and other nudibranchs including the Frosted Nudibranch (Dirona albolineata) and the White and Orange-tipped Nudibranch (Janolus fuscus).

The bottom of the stalks are mostly darker, dead zooids (an individual of the bryozoan colony). A specialized zooid called Avicularium that looks similar to a bird-head keeps other organisms from resting on and growing on the bryozoan. They will also catch small crustaceans and bring it to the mouth of the zooids to feed it.

Kelp Encrusting Bryozoan

Author: Madeleine Dorion

Common Name: Kelp-encrusting Bryozoan, Kelp Lace Bryozoan, White Encrusting Bryozoan

Scientific NameMembranipora serrilamella

Membranipora serrilamella get their more common name, Kelp-Encrusting Bryozoa, for fairly
obvious reasons. They grow on/encrust kelp with a white or silver crust that grows in circular
patches. Each of these circular patches are constructed by lots of tiny rectangular boxes, called

The small radial growths often merge with others patches of zooids to create colonies, with new
growth continuing around the edges. Sometimes colonies do not get along, in which case, they
will compete for space.

Kelp-encrusting bryozoa can grow in waters up to as deep as 180 meters.  It is not only found
growing on kelp but often on other solid surfaces such as rocks. It’s annual burst of growth occurs during summer months and during this time it can grow several millimeters in diameter per day. By the end of the summer some kelps are completely engulfed by a white crust.