The dark blue fan-like creature is from the Leigh marine reserve. Bugula neritina is a colonial animal that grows in upright, bushy, branching tufts, up to 15 cm or so in height, that are often mistaken for a seaweed. They are usually a dark red-purple or purple-brown, though occasionally they are a dull, dark red. Some of the details described below can be seen with a hand lens; others require a microscope. The individuals in a colony are called zooids. They consist of soft parts, called the polypide, enclosed in a rigid box, called the zooecium (Greek for "animal house"). Each branch in the colony is made up of a double row of zooecia, with all the zooecia facing in the same direction. The zooecia are stacked end-to-end, one above another, within each row. The two rows in a branch are staggered, so that the top of one zooecium comes to about the middle of the one next to it.

Reefs in tropical to sub-tropical areas. But also on the continental shelf off Otago. Not only do they live on reefs, but some deep reefs (like those just off the Otago Peninsula) are built of bryozoans!

Plant plankton and bacteria from the water. Bugula neritina feeds with 20-24 white, translucent tentacles that are arranged in a cone-shaped funnel surrounding the mouth at the head end of the polypide. This crown of tentacles is called a lophophore. The tentacles are long and relatively stiff, with cilia arrayed along their inner faces and sides. To feed, the lophophore and upper end of the polypide are pushed out of the zooecium through an opening near the top of the membranous front of the zooecium. Currents produced by the beating of the cilia carry food particles (primarily microscopic plankton) down along the tentacles to the mouth.

Bugula neritina zooids are hermaphroditic. Zooids release eggs around the middle of their lifespan but don't release sperm until near the end, thus preventing self-fertilization. Each zooid produces a single, dark-brown embryo at a time, which is brooded in a smooth, white, globular structure at the top of the zooecium, called an ovicell. The ovicells are conspicuous and often abundant, appearing as numerous small white beads concentrated in the older and more central part of a colony. When released from the ovicell, usually around dawn, the larvae have neither mouths nor digestive tracts and are incapable of feeding. They settle onto hard surfaces within about 2-10 hours, and metamophose into the adult form. Most settlement occurs in summer and fall in temperate waters, and in late fall to early spring in warmer waters. The initial zooid buds off others, which in turn bud off others, enlarging the colony. Sexual maturity is reached at 6-8 weeks, and colonies can live for over a year. There are over 6000 species of bryozoans, more than 1000 in N.Z.! They can range from tiny crusts or lentil-shaped colonies to large, tree-like shapes. Bryozoans produce remarkable chemicals and are currently being used in cancer research. Oamaru limestone is made primarily of bryzoan skeletons. Photo contributed by Abigail Smith)



Bugula neritina attracted interest as a source of cytotoxic chemicals, bryostatins, under clinical investigation as anti-cancer agents.

http://www.exoticsguide.org/bugula_neritina