Biofouling Guidelines

IMO Updates

IMO Biofouling Guidelines

At its 80th session (July 2023), the Marine Environment Protection Committee (MEPC) adopted the 2023 Guidelines for the control and management of ships' biofouling to minimize the transfer of invasive aquatic species (Biofouling Guidelines) (resolution MEPC.378(80)). While these Guidelines are not mandatory, they provide a globally consistent approach to the management of biofouling and include recommendations for:

1. Ship-specific assessment of biofouling risk profiles for hull and niche areas, including monitoring of relevant risk parameters during operation.                        

2. Scheduled inspections to determine the level of biofouling and the condition of the AFS, based on the ship-specific risk profile, with inspections also serving as contingency actions. 

3. Maintaining a ship-specific Biofouling Management Plan (BFMP) and a Biofouling Record Book (BFRB).

4. The AFS installation and maintenance, a fouling‑rating scale for inspection areas, and procedures for both proactive and reactive cleaning.

The BFMP and BFRB may be either standalone documents or partially or fully integrated into the vessel’s existing operational manuals and/or planned maintenance system.

Biofouling Management Plan (BFMP) 

The BFMP should be vessel-specific and should provide a description of the biofouling management strategy for the vessel with sufficient details to allow the vessel’s master, the designated ship’s officer, or crew members to understand and implement the biofouling management strategy. It should address, at a minimum, relevant parts of IMO Guidelines as follows:

1. Identification of the officer, or the position (e.g., chief engineer), responsible for the BFMP, confirming that the plan is properly implemented

2. Details of the AFS installed and where it is installed

3. Details of the recommended operating conditions which are suitable for the selected AFS to avoid deterioration of anti-fouling coating (AFC), including recommended conditions such as temperature, salinity and speed 

4. Details of expected AFC efficacy throughout its lifetime, including the need for inspection or maintenance, if relevant

5. Description of monitoring biofouling risk parameters

6. Regime for cleaning, if any

7. Details of hull and niche areas where biofouling may accumulate 

8. Schedule for fixed inspections of areas

9. Procedures for reactive cleaning actions should be performed if triggered by inspection results

10. Contingency action plan based on specific triggers from monitoring biofouling risk parameters

11. Regime for repairs, maintenance and renewal of AFS, when relevant, in accordance with the manufacturer's instructions 

12. Process for monitoring and maintenance of the marine growth prevention system (MGPS) as per the manufacturer's instructions to confirm their effectiveness in minimizing biofouling

13. Details of the documentation/reports required to document biofouling activities

     

Biofouling Record Book (BFRB)

The BFRB is recommended to be maintained for each vessel to record details of all inspections and biofouling management measures undertaken on the vessel. This is to assist the shipowner and operator in evaluating the efficacy of the specific AFS and operational practices on the vessel, and of the BFMP. The BFRB could also assist interested State authorities to quickly and efficiently assess the potential biofouling risk of the vessel and thus minimize delays to ship operations.

The BFRB is recommended to be retained on the vessel for the life of the vessel.

All biofouling management activities should be recorded in a BFRB, including the following: 

1. Details of repair and maintenance to the AFS, including date, location and areas of the ship affected, including the percentage of the ship that was recoated with AFC — this is in addition to recordings in the International AFS Certificate.

2. Details of repair and maintenance to the MGPS, including date, location and areas of the ship affected.

3. The initial date, final date, duration in hours/days and location of in-water inspections, including the inspection report.

4. The initial date, final date, duration in hours/days and location of cleaning (in water or in drydock), including a cleaning report. 

5. Details of when the ship has been operating outside its normal operating profile, including any details of when the ship was laid up or inactive for extended periods of time.

6. Details of relevant performance monitoring parameters used to determine inspection intervals.

7. A copy of the cleaning report.

8. Description of contingency actions taken, including date, time and location. 

During an inspection, niche areas in the ship-specific BFMP should be inspected as a priority, and all inspected areas should be allocated a fouling rating number in line with the extent of fouling as defined in Table 1.

Brazil

The Directorate of Ports and Coasts (DPC) of the Brazilian Navy issued Ordinance DPC/DGN/MB No. 476/26 dated June 3, 2026, which approved the third revision of the Maritime Authority Standards for the Prevention of Environmental Pollution Caused by Vessels and Platforms – NORMAM-401 Rev.3. Chapter 4 of NORMAM-401 establishes a comprehensive regulatory framework for biofouling control, aligned with the IMO Biofouling Guidelines (Resolution MEPC.378(80)).

Under NORMAM‑401, all vessels exceeding 24 meters in length intending to enter Brazilian Jurisdictional Waters (AJB) must:

• Maintain a Biofouling Management Plan (BFMP).
• Maintain a Biofouling Record Book (BFRB).
• Ensure the vessel’s hull condition does not exceed Biofouling Level 1 (microfouling) upon entry into AJB.

The minimum contents of the BFMP and BFRB are indicated in Annex H of NORMAM-401.

Where biofouling at Level 2 or above is identified, recommended actions include cleaning with capture of residues, enhanced inspection frequency, and, if deterioration of antifouling coating is observed, drydocking for maintenance. Vessels intending to conduct in‑water cleaning must obtain prior authorization from the local Maritime Authority agent, preferably a minimum of ten days in advance.

The biofouling level scale and respective cleaning practices are indicated in Annex J of NORMAM-401.

Annex I of NORMAM‑401 also divides the Brazilian coastline into three marine biogeographical regions (North, Northeast, South/Southeast) and vessels navigating between these regions must ensure ongoing compliance with the requirements described above.

Noncompliance

Ordinance DPC/DGN/MB No. 476/26 also defers the enforcement of penalties for noncompliance (including warnings, fines and operational restrictions) until January 10, 2028, following formal administrative procedures conducted under Law No. 9.605/1998 and NORMAM‑401. However, the requirement to request authorization for in‑water cleaning has been in force since June 2025.

Actions for Compliance

ABS strongly encourages operators calling at Brazilian ports, or planning operations in Brazilian waters, to:

• Review and update their BFMPs.
• Ensure BFRBs are complete and up to date.
• Conduct timely inspections and cleaning to maintain biofouling at or below Level 1.
• Coordinate early with local agents regarding any in‑water cleaning needs.
• Maintain all supporting documentation onboard for inspection.

Further details on Brazil’s requirements can be found in NORMAM-401.

Australia

The Australian biofouling management requirements for commercial vessels (ABFMR-CV) introduced biofouling requirements for all international vessels arriving in Australian territorial seas (i.e., within 12 nautical miles from the coast), including commercial ships, offshore support vessels and yachts.

Vessel operators are required to report whether they can demonstrate compliance with one of the following three proactive biofouling management options:

1. Effective Biofouling Management Plan (BFMP) and Biofouling Record Book (BFRB).

An effective BFMP and BFRB must meet the minimum standards, set out in Appendix A of ABFMR-CV, based on the IMO’s 2023 Guidelines for the control and management of ship’s biofouling to minimize the transfer of invasive aquatic species (resolution MEPC.378(80)). 

• An effective BFMP must be vessel-specific, included in the vessel’s operational documentation and detailed enough for the crew to implement the specified biofouling management activities.

• The BFRB should provide a complete and up-to-date record of all biofouling management activities undertaken on the vessel, maintained from the date the BFMP enters into force and retained for the life of the vessel. The BFRB may be electronic or in hard copy and must be available for inspection on request.

2. Biofouling Cleaning within 30 days of arrival.

If the vessel has been cleaned of all biofoulings within 30 days prior to arrival in Australian territorial seas, a cleaning report and supporting evidence (photographs and/or video) in accordance with the minimum standards in Appendix B of ABFMR-CV must be available on request.

3. Alternative Pre-Approved Biofouling Management Method

An alternative biofouling management method that appropriately manages the biosecurity risk associated with the vessel’s biofouling, supported by sufficient evidence, may be approved specific to the vessel and the voyage. The application must be submitted to marinepests@aff.gov.au no later than 30 days prior to arrival in Australian territorial seas. If approved, the written approval and any other documents specified in the approval must be available on request.

Reporting 

The information shall be provided through the mandatory pre-arrival report (PAR), via the Maritime and Aircraft Reporting System (MARS), between 96 and 12 hours before the estimated time of arrival of the vessel at its first port in Australian territory.  

In-Water Cleaning in Australian Waters

The approval process for conducting in-water cleaning or treatment in Australian waters is complex and varies between locations. Therefore, please ensure you contact the relevant authorities for permission well in advance of your proposed cleaning activity to allow sufficient time to consider your request.

Verification on Arrival

To confirm compliance, the Department of Agriculture, Fisheries and Forestry conducts inspections to verify that biofouling management procedures reported by vessels have been carried out. Biosecurity officers may ask questions and inspect documents to confirm the effectiveness of the management practices. If the department determines that the vessel’s biofouling has not been managed in accordance with these requirements, a further detailed biofouling assessment will be conducted. The department may also conduct inspections of vessels’ submerged hull and niche areas to inform assessments of whether the vessel presents an unacceptable biosecurity risk associated with biofouling.

Noncompliance

• Vessels that cannot demonstrate compliance with any of the proactive biofouling management options will be subject to further pre-arrival reporting questions through MARS. 

• Vessel operators who demonstrate compliance with one of the three proactive options are eligible for less intervention. If compliance with a proactive biofouling management option is reported, required documentary evidence must be available during the vessel inspection. 

Actions for Compliance 

ABS strongly encourages operators calling at Australian ports, or planning operations in Australian waters, to:

• Select one of the three proactive biofouling management options and ensure compliance:

1. Update their BFMPs and BFRBs, or 

2. Ensure the vessel has been fully cleaned of biofouling within 30 days prior to arrival in Australian territorial seas, or

3. Apply in advance for approval of an alternative biofouling management method. 

• Maintain all supporting documentation of the applicable method on board and readily available for inspection.

• Contact the relevant authorities well in advance of any intended in-water cleaning or treatment to allow sufficient time for assessment and approval.

• Provide biofouling management information on time through the mandatory PAR using MARS.

Further details on Australia’s requirements can be found here.

California

The California Code of Regulations (CCR), under Article 4.8, introduced the following biofouling requirements to minimize the transport of invasive aquatic species into the waters of the state of California, for all vessels of 300 gross tons and greater that can carry ballast water and that arrive at a California port.  

1. Biofouling Management Plan (BFMP).

Any ship that arrives at a California port shall maintain a ship-specific BFMP on board. This plan shall:

• Provide a detailed description of the biofouling management strategy for the vessel. 

• Be regularly reviewed and updated. 

• Maintain consistency with the IMO Biofouling Guidelines.

• Describe the BFMP and anti-fouling systems specifically used for the hull and each of the vessel's niche areas. For each anti-fouling system listed, specific required information shall be included, such as the manufacturer name, model name, product number (if applicable) and the date each system was installed or applied.

If a ship arrives at a California port for the first time since the most recent regularly scheduled out-of-water maintenance or since delivery (for newbuilds, if no such maintenance has occurred), without a compliant BFMP, a 60‑day grace period from the date of arrival shall apply, to allow development of the required documentation.

Upon request, the plan shall be made available for inspection and review.

2. Biofouling Record Book (BFRB).

Any ship that arrives at a California port shall maintain a BFRB on board. The BFRB shall:

• Contain details of all inspections and biofouling management measures undertaken.

• Maintain consistency with the IMO Biofouling Guidelines.

• Include a description of all completed niche area management practices.

If a ship arrives at a California port for the first time since the most recent regularly scheduled out-of-water maintenance or since delivery (for newbuilds, if no such maintenance has occurred), without a compliant BFRB, a 60‑day grace period from the date of arrival shall apply to allow development of the required documentation. During this period, records detailing all inspections and biofouling management measures undertaken on the vessel shall be maintained and made available to the California State Lands Commission staff upon request.

3. Mandatory Biofouling Management of the Vessel's Wetted Surfaces.

Any ship arriving at a California port shall manage biofouling on the wetted surfaces of the vessel, except those niche areas, in any of the following ways:

• Anti-fouling coating: The anti-fouling coating shall not be aged beyond its effective coating lifespan, as documented in the vessel’s BFMP. If the anti-fouling coating is aged beyond the effective coating lifespan, the BFMP shall describe how biofouling will be managed after the expected coating lifespan is exceeded. All management actions should be documented in the BFRB.

• Vessel not using an anti-fouling coating: The BFMP shall describe how biofouling will be managed in the absence of an anti-fouling coating. All management actions should be documented in the BFRB. 

Niche areas should be managed using one or more practices that are appropriate for the vessel and its operational profile, and may include sea chests, sea chest gratings, bow and stern thrusters, bow and stern thruster gratings, fin stabilizers and recesses, out-of-water support strips, propellers and propeller shafts, and rudders. Niche area management practices should be described in the BFMP, and the completed actions should be documented in the BFRB. If any of these practices are not conducted as planned, the reason(s) shall be documented in the BFRB.

4. Mandatory Biofouling Management for Vessels that Undergo an Extended Residency Period

Vessels that have remained in a single port for 45 or more consecutive days must comply with the following biofouling management requirements upon arrival at a California port:

• Biofouling in the niche areas must be managed in a manner consistent with the niche area management practices described in the vessel’s BFMP. 

• Any activities (including in-water inspection, in-water cleaning, in-water treatment or out-of-water maintenance) conducted to manage biofouling on niche areas, or any wetted surface that accumulates as a result of the extended residency, shall be documented in the BFRB.

5. Alternatives to the Requirements

Petitions for alternative management actions must be submitted in writing and may be approved by the Commission’s Marine Environmental Protection Division Chief before the vessel arrives at a California port, if they meet the purpose of the regulations. If the approved conditions are not met, the alternative measures may be withdrawn.

Reporting 

The Marine Invasive Species Program Annual Vessel Reporting Form (AVRF) must be submitted once per calendar year and at least 24 hours prior to a vessel’s first arrival at a California port through the web-based platform. It can be submitted earlier during the calendar year (e.g., submitted in January for the first arrival in March) by anyone affiliated with the vessel (e.g., ownership, management, crew, agent). It is recommended to retain the AVRF for at least two years.

Actions for Compliance 

ABS strongly encourages operators calling at California ports, or planning operations in California waters, to:

• Review and update their BFMPs.

• Ensure BFRBs are complete and up to date.

• Manage biofouling on all wetted surfaces, including niche areas, through appropriate measures such as effective anti-fouling coatings.

• Verify anti-fouling coating lifespan and confirm that coatings remain within their effective service life.

• Maintain all supporting documentation on board and available for inspection.

• Submit the required AVRF accurately and on time, at least 24 hours before the vessel’s first arrival at a California port in each calendar year.

Further details on California’s requirements can be found here.

New Zealand

The Craft Risk Management Standard (CRMS) for vessels outlines all biosecurity requirements for international vessels arriving in New Zealand, including biofouling. All vessels must provide evidence of biofouling management prior to arrival and ensure that when the vessel enters New Zealand’s territory, it has a “clean hull” in accordance with the thresholds below, based on its “category” (Short-Stay Vessel or Long-Stay Vessel). 

To meet the biofouling requirements, one of the following methods, along with relevant documentation, may be implemented:

1. Continual Hull Maintenance Using Best Practices (short-stay vessels)

This includes:

• Application of anti-fouling coatings

• Implementation of a BFMP and maintenance of an up-to-date BFRB

• Operation of marine growth prevention systems

• In-water inspections with biofouling removal

Verifiable evidence, such as the BFMP and BFRB, dates and reports of drydocking, current anti-fouling system certificates, vessel operational history, evidence of independent inspections and ongoing maintenance, etc., shall be available.

2. Clean Before Arrival (recommended for long-stay vessels)

A vessel that has had its hull and niche areas inspected and cleaned within 30 days before arrival in New Zealand shall maintain evidence, such as hull cleaning, drydocking reports or a vessel’s biofouling inspection report*.

*Vessel biofouling inspection reports need to comply with the requirements of the CRMS for vessels. For a commercial vessel that has a 5-year drydocking cycle and has not operated outside of its profile, vessel inspections should be conducted annually for the first two years, then every six months. If a vessel falls outside its operational profile, then vessel inspections should be more frequent.

3. Clean Out-of-Water on Arrival (recommended for vessels coming to New Zealand for refit or repair)

The vessel must have a confirmed booking at a Ministry for Primary Industries (MPI)-approved haul-out facility to remove biofouling, with entry to this facility within 24 hours of arrival in New Zealand. This option is available for smaller vessels, as large drydocks currently do not exist in New Zealand. Evidence of booking with the provider will be available. 

4. Treat on Arrival

This refers to the application of available approved treatments listed in the Approved Biosecurity Treatments. This does not include biofouling removal at an approved haul-out facility. In‑water cleaning of international vessels in New Zealand is allowed only through approved providers. Currently, a system in Auckland has been provisionally approved and can be used for arriving vessels, including cruise ships.

If the vessel can't meet the standard using one of these measures, operators may develop a Craft Risk Management (CRM) plan that details alternate but equivalent measures to manage biofouling and submit via email to standards@mpi.govt.nz, for MPI’s consideration of approval.

Cruise vessels should comply with long-stay requirements or operate under an MPI-approved system to manage topside and biofouling risk.

Reporting

An operator, or person in charge, of a vessel must ensure that the information required under section 1.4 of the CRMS is received by MPI at least 48 hours prior to the vessel’s entry into New Zealand territory. This information may include vessel details, voyage details and biofouling information (some of which may be held on board and presented to MPI if requested by an inspector).

Noncompliance 

On arrival, information regarding the vessel’s biofouling maintenance history and records of biofouling management or hull cleaning will be requested. If verifiable evidence of the application of the compliance methods above cannot be provided, the MPI may:

• Require a hull inspection on arrival to New Zealand (if directed to undertake a hull inspection on arrival, the operator can choose the inspection provider)

• Restrict the vessel’s itinerary in New Zealand

• Restrict entry of the vessel to New Zealand

• Require the vessel to be cleaned within 24 hours by an approved provider in New Zealand

These measures will be at the expense of the vessel owner or operator and may result in significant delays.

Actions for Compliance 

ABS strongly encourages operators calling at New Zealand ports, or planning operations in New Zealand waters, to:

• Review and update their BFMPs and BFRBs

• Implement hull maintenance practices, such as anti-fouling coatings, Marine Growth Prevention system (MGPS), timely and regular inspections, and cleaning of the hull

• Maintain all supporting documentation on board in accordance with MPI requirements, such as reports and photos from a recent hull inspection or recent hull clean, anti-fouling certificates, records of contingency planning, BFMP and BFRB

• Self-assess their vessel using the MPI Biofouling Compliance: Self-Assessment Tool

• Submit the required pre-arrival report to MPI accurately and on time, along with all the required documentation

• Inspect and, if necessary, clean the hull and niche areas within 30 days before arrival in New Zealand (recommended for long-stay vessels), and ensure that the relevant documentation is available

   

Further details on New Zealand’s requirements can be found here.

ABS Support

ABS has published the Guidance Notes on Biofouling Management Plans, which provides practical assistance to interested parties on the development of biofouling plans. 

In addition, ABS can provide support in the following areas: 

• Development of the Biofouling Management Plan

• Guidance on selecting the appropriate anti-fouling coating for new construction projects 

• Evaluation of planned maintenance schemes

• Assessment of the suitability and lifespan of applied coatings and fouling control systems

Should you require assistance in understanding these requirements or assessing the compliance status of your fleet, ABS remains available to support you.