Biofouling Management

Biofouling management involves the inspection, cleaning, and prevention of marine growth on submerged port structures to protect infrastructure integrity, biosecurity, and ecosystem health (Hopkins et al., 2021). This may include, among others, scheduled inspection and cleaning of piles, seawalls, and pontoons, use of environmentally responsible cleaning methods, containment and disposal of removed material, application of low toxicity or non toxic antifouling coatings, coordination with vessel biofouling requirements, and monitoring for invasive marine species.

For DMC ports, biofouling management can prevent the spread of invasive species, protect marine biodiversity, maintain structural integrity and hydraulic performance, reduce the need for high impact repairs, and support national biosecurity objectives (Hopkins et al., 2021). Tropical and subtropical waters, which surround many DMC ports, can accelerate biofouling rates, making regular inspection and maintenance particularly important.

Biofouling is the accumulation of marine organisms on submerged structures, including barnacles, mussels, algae, tubeworms, and other sessile species. In ports, biofouling affects submerged infrastructure (piles, seawalls, pontoons, outfalls), mooring systems, buoys, and submerged maintenance equipment. Biofouling may increase hydrodynamic drag, accelerate corrosion, provide habitat for invasive species, and block water intakes and pipework (Hopkins et al., 2021).

Effective biofouling management requires, among others, scheduled inspection of submerged structures by divers, remote operated vehicles (ROVs), or unmanned surface vessels; cleaning using appropriate methods (mechanical scraping, high pressure water, ultrasonic, or chemical), selected to minimize environmental impacts; containment of removed material to prevent dispersal of invasive species and debris; application of antifouling coatings where appropriate; and coordination with broader port biosecurity management (Hopkins et al., 2021).

Sustainable antifouling coatings have evolved to reduce environmental impacts associated with traditional biocidal coatings . Modern options include, among others, silicone based foul release coatings that prevent adhesion rather than poisoning organisms, biomimetic coatings based on natural non fouling surfaces, and encapsulated biocide systems that minimize release to the water column.

International Maritime Organization (IMO) conventions, including the International Convention on the Control of Harmful Anti fouling Systems on Ships (AFS Convention; IMO, 2001), have progressively restricted the use of harmful biocides, such as tributyltin (TBT) and other organotins (Convention in force 17 September 2008) and cybutryne (not to be applied or re-applied from 1 January 2023).

Invasive species may disrupt native ecosystems, damage aquaculture and fisheries, and clog water intakes. National biosecurity frameworks in New Zealand, Australia, and other jurisdictions impose biofouling management requirements on vessels, and port operators may play complementary roles in managing biofouling on port infrastructure.

For DMC ports operating in tropical waters, biofouling rates may be higher than in temperate environments, requiring more frequent inspection and cleaning. The IMO 2023 Biofouling Guidelines (resolution MEPC.378(80)) address ships' biofouling and encourage States to provide information on the location and terms of use of inspection and cleaning services and facilities, and States and port authorities to avoid ships waiting offshore so that anti-fouling systems can operate effectively. Coordinating port and vessel biofouling management supports invasive species prevention.