Marine biofouling adversely affects your vessel's performance. Biofouling occurs when marine organisms attach to and grow on objects such as hulls, anchors, cables, fenders, cordage, tenders – in fact, just about anything that's in regular contact with the sea. Marine pests that hitch a ride into Australian waters can compete with native species, spread disease and devastate our marine environment. At least 250 introduced species are already established in Australian ports and waters, and an estimated three quarters of these arrived as biofouling organisms on vessels.
To help reduce the risk of biofouling entering Australian waters on your vessel the Department of Agriculture and Water Resources recommends that you apply the principles of the National Biofouling Management Guidelines for Recreational Vessels and that:
- your hull has an effective anti-fouling coating that is less than 12 months old
- you clean your vessel's hull and any equipment that has been in contact with seawater at your last port of call or within one week prior to arriving in Australia. (Note: Biofouling removal should take place at a registered haul-out facility using a high-pressure water cleaning system.
The Department of Agriculture and Water Resources recommends that you check your internal seawater systems, including your sea strainer and other on-board systems that use seawater, and clean any build-up of marine growth. Seek assistance from your mariner if required.

These areas are risks for biofouling on yachts because:
- Ancillary gear - During extended port stays biofouling can build up and attach to ancillary gear. Routine maintenance is recommended for al ancillary gear in contact with seawater.
- Internal Water System – Seawater is drawn into yachts for use in internal water systems such as engine cooling, toilet flushing and galley sinks. Port environments can provide the opportunity for marine species to enter internal seawater systems. It is recommended that inspection and maintenance be carried out regularly.
- Underwater hull areas – With prolonged exposure to seawater, areas on the hull pose the greatest risk from biofouling. The correct application and maintenance of antifouling paint is highly recommended to prevent build-up of biofouling. A regular maintenance program for the antifouling paint system will also reduce inspection time, when arriving in Australia.
The Department of Agriculture and Water Resources recommends that you establish a voyage history and biofouling maintenance log, which includes details of your last hull clean and anti-fouling renewal. Keeping these records will assist in best practice biofouling management and will also assist biosecurity officers during your first port pratique inspection.