Botryllidae

Susceptible crops: These organisms pose a significant threat to shellfish farming, particularly oyster and mussel aquaculture. They also heavily colonize the netting and cage infrastructure used in finfish farms, creating heavy biofouling that complicates maintenance and reduces water flow.

Biology and life cycle: Botryllids form colonies where individual zooids are embedded in a common tunic. Their life cycle includes a short-lived, free-swimming larval stage that is highly specialized for finding a suitable hard substrate. Once settled, they grow rapidly through both sexual reproduction and budding, forming extensive mats covering surfaces.

Character of damage and harm: The primary harm is caused by competitive exclusion and physical covering of the cultured hosts. By covering the shells of mollusks, they restrict feeding and respiration. The sheer weight of mature colonies can cause structural damage to cages and buoyancy devices, leading to economic losses in the farming sector.

Control measures:

• Regular mechanical cleaning of infrastructure using high-pressure sprayers.
• Application of non-toxic, antifouling coatings suitable for aquaculture environments.
• Exposure of farming equipment to air and sunlight to desiccate and kill adhering colonies.
• Strategic timing of harvesting and equipment maintenance to minimize the impact of peak spawning seasons.