Hull fouling is difficult to control because organisms grow directly on the submerged parts of ships in ways that are hard to detect, access, and fully remove.
Key reasons
- Biofouling communities include many microscopic and small organisms that are easily overlooked during inspections, so ships can carry nonnative species even after apparent cleaning.
- Organisms settle in crevices, niche areas (sea chests, rudders, propellers, intakes), and rough surfaces that are physically hard to reach and clean effectively.
- A wide variety of species can attach and survive long voyages, and current regulations and maintenance practices are less standardized and less strictly enforced than for ballast water, leaving this vector relatively unmanaged.
