Biofouling on pearl oysters, and the equipment used in culture of these oysters, is a major cost to the pearl industry throughout Australia. Rapid biofouling necessitates frequent cleaning, a process that is labour and capital intensive. The cost of cleaning, as estimated by the Pearl Produces Association, is approximately $15 to $20 per shell per year. The cost to the industry as a whole is likely to exceed $20 million/annum. Indirect costs include losses due to shell mortality, reduced growth rates and reduced pearl production from effects to nacre deposition.
Biofouling of oysters and equipment presents several problems if unattended. Invertebrates dominate fouling communities common to the pearl industry and these compete directly with pearl oysters for food. Several organisms, such as the sponge Cliona (red arse) and boring shellfish, directly attack the pearl oysters and result in shell damage or mortality. Excessive fouling of underwater surfaces also increases drag forces and increase the susceptibility of lines to storm damage. It is noteworthy that frequently cleaning is also problematic since evidence suggests that this type of handling reduces shell growth.