Selenaria maculata

Selenaria maculata is a marine colonial organism belonging to the phylum Bryozoa, class Gymnolaemata, and order Cheilostomatida. It is recognized as a significant pest in aquaculture, particularly in shellfish farming, due to its habit of forming extensive encrusting colonies on artificial substrates, cages, and collection equipment used for cultivating bivalves.

The biology of this species is unique because its colonies possess specialized structures called vibracula, which allow the colony to move slowly across surfaces. This mobility provides Selenaria maculata with a competitive advantage, enabling it to aggressively colonize limited spaces and outcompete other organisms, which can lead to dense coverage of aquaculture infrastructure.

The life cycle begins with a free-swimming larva that settles on hard structures, where it undergoes metamorphosis into a primary zooid. This zooid then reproduces asexually through budding, rapidly expanding the colony. The ability to settle in diverse marine environments allows the species to proliferate throughout the growing season of commercial mollusks.

The damage caused by these bryozoans is primarily mechanical and environmental. By encrusting netting and mesh, they obstruct water flow, reducing the supply of oxygen and phytoplankton necessary for the growth of oysters, mussels, or scallops. Furthermore, the added weight and surface area increase drag, which can lead to the structural failure of aquaculture equipment.

Control measures rely heavily on integrated farm management. Routine inspection and mechanical removal using high-pressure sprayers are common practices. Additionally, the application of non-toxic anti-fouling coatings is highly recommended to discourage larval settlement. In some instances, periodic air-drying of equipment is sufficient to eliminate established colonies.