Vessels above 24 meters must plan and record proactive biofouling management measures to document a ‘clean hull’ on entry into Brazilian waters, or undertake reactive in-water hull cleaning to achieve the same. While enforcement of associated sanctions has reportedly been deferred to 10 January 2028, the ‘clean hull’ requirement is already in force, and compliance is expected to be monitored.
Updated 17 June 2026
Published 10 July 2025
Protecting Brazil’s marine and coastal biodiversity
In June 2025, the Brazilian authorities amended NORMAM-401/DPC, the regulations governing the prevention of environmental pollution from vessels and platforms, to include a dedicated section on biofouling management. The amendments aim to safeguard Brazil’s marine biodiversity by further reducing the risk of vessels introducing invasive aquatic species into its waters.
To protect the diverse and distinct ecosystems along Brazil's extensive coastline, the amended regulation also defines three domestic marine biogeographic regions (see image below) and imposes additional biofouling requirements on vessels operating between them.
Arriving in Brazil with a clean hull
According to our local correspondent Representações Proinde Ltda., Brazil’s biofouling management regulation aligns with the IMO 2023 Biofouling Guidelines (MEPC.378(80)). It applies to vessels above 24 meters in length and affects both vessels entering Brazilian waters and those operating between the domestic biogeographic regions. Affected vessels are required to:
Implement and retain onboard a vessel-specific Biofouling Management Plan and Biofouling Record Book in line with the IMO guidelines, supporting a proactive maintenance and cleaning regime that takes into account operational risk factors such as changes in trading area or periods of inactivity.
Maintain a clean hull at all times, where ‘clean’ means no biofouling other than a slime layer (microfouling) and only minimal presence of visible fouling species (macrofouling). This corresponds to a fouling rating 1 or lower, as defined in Annex J of the regulation.
Arrange reactive hull cleaning where necessary, i.e. where fouling reaches a rating 2 or higher. In-water hull cleaning in Brazilian waters must be requested at least 10 days prior to the planned operation using the application form found in Annex K of the regulation.
Key terminology
Biofouling is the accumulation of aquatic organisms such as microorganisms, including pathogens, plants and animals on surfaces and structures immersed in or exposed to the aquatic environment.
Fouling rating is the allocation of a number for a defined inspection area of the ship surface based on a visual assessment, including description of biofouling present and percentage of macrofouling coverage.
In-water cleaning is the removal of biofouling from a ship's hull and niche areas while in the water.
Invasive aquatic species are non-native species to a particular ecosystem which may pose threats to human, animal and plant life, economic and cultural activities and the aquatic environment.
Microfouling is biofouling caused by bacteria, fungi, microalgae, protozoans and other microscopic organisms that creates a biofilm also called a slime layer.
Macrofouling is biofouling caused by the attachment and subsequent growth of visible plants and animals on structures and ships exposed to water. Macrofouling is large, distinct multicellular individual or colonial organisms visible to the human eye such as barnacles, tubeworms, mussels, fronds/filaments of algae, bryozoans, sea squirts and other large attached, encrusting or mobile organisms.
Mitigating measures
While the operational requirements of the new Brazilian biofouling management regulation took effect on 17 June 2025, our correspondent indicates that enforcement of the sanction and penalty phase under Chapter 4 of NORMAM-401/DPC has been deferred, with a current start date of 10 January 2028. However, authorities are nevertheless expected to monitor technical and operational compliance during this period of grace and vessels trading to or within Brazilian waters are therefore advised to:
Update onboard procedures accordingly, taking guidance from relevant IMO instruments on biofouling management (MEPC.378(80)) and in-water cleaning (MEPC.1/Circ.918). Proinde’s Practical Gude on Ballast Water and Biofouling Management in Brazil may also serve as a useful resource for ensuring compliance.
Contact local agents and port authorities well in advance to arrange reactive hull cleaning where required, noting that in-water cleaning may not be available or permitted in all Brazilian ports. Confirm any regional or local restrictions and consider inspections and cleaning prior to arrival in Brazil.
Document all hull cleaning activities and compliance efforts carefully.
Review and, where necessary, amend charterparty clauses to clearly allocate responsibilities for underwater inspection and hull cleaning in light of applicable regulatory thresholds.
It is also worth noting that Brazil defines its “jurisdictional waters” as including internal waters, the territorial sea, and the exclusive economic zone (EEZ), extending up to 200 nautical miles from coastal baselines, as well as waters overlying the extended continental shelf.
We are grateful to our Brazilian correspondent, Representações Proinde Ltda., for drawing our attention to these regulatory developments and refer to its website for further details.
Biofouling management outlook
The IMO has now agreed to deveop a legally binding framework for the control and management of ships' biofouling to minimize the transfer of invasive aquatic species, a “biofouling management convention”. The work on such a convention will commence in 2026, and a draft legal framework and recommendations on the way forward not finalised until 2029. Ratification to the agreed level will then be required for entry-into-force.
An international convention will provide a unified framework for addressing biofouling management globally and help avoid the patchwork of national regulations that can be impractical for the industry. It will also help ships gain access to in-water cleaning in more places than today. Meanwhile, the following Gard articles may be of interest:
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