Op-Ed: Biofouling—A challenge the industry can’t ignore

Nick Cowley.

By Nick Cowley, president of Cathelco

The relationship between biofouling management and the maritime industry is a complicated one. Despite the proven benefits of limiting biofouling growth—including emissions reduction, protection of ecosystems, and improved vessel performance—it remains an overlooked solution for shipowners.

The 83rd session of the International Maritime Organization’s (IMO) Marine Environment Protection Committee (MEPC) in April focused heavily on reducing greenhouse gas emissions. However, another key decision was also made, to begin work on a legally binding international convention on the control and management of ships’ biofouling. 

As a result, biofouling is finally being recognized and treated as a key driver of fuel consumption and emissions, rather than just a gateway for invasive species. Although the framework’s implementation will not begin until 2026, with a convention unlikely to be finalized before 2029, acknowledging the problem is a good first step. It’s up to vessel owners now to steer the course.

Why biofouling should be taken seriously

Unmanaged hulls contribute to vessel damage, increased drag and fuel consumption. As well as resulting in decreased speeds and reduced fuel efficiency, biofouling is one of the main culprits for the transportation and introduction of invasive species in vessels, according to the U.S. Environmental Protection Agency. With levels of increased fuel consumption reaching as high as 20% with light slime, and by up to 85% with heavy calcareous fouling, this isn’t a minor issue to turn a blind eye to.

The conversation about biofouling has been treated as a relatively trivial topic in comparison to other decarbonization measures such as the Carbon Intensity Indicator (CII) and the Energy Efficiency Existing Ship Index (EEXI). This suggests that the industry is overlooking the environmental benefits of adopting biofouling management strategies.

In reality, practical approaches to combat biofouling offer several operational benefits, such as lowering emissions, preserving marine ecosystems, and return on investment. The IMO’s new framework following MEPC83 means that prioritizing biofouling management measures will ensure that vessel owners align with requirements and avoid legal obstacles and costly penalties.

California sets the bar for biofouling regulation

The international landscape is currently a patchwork of regional, national, and local biofouling regulations. This fragmented approach creates inconsistent compliance burdens, restricts access to in-water cleaning, and adds layers of complexity for shipowners, operators, and managers.

California stands out as one of the most stringent jurisdictions. Since October 2017,  vessels calling at its ports have been subject to the California Biofouling Management Regulations, which go beyond the IMO’s voluntary guidelines by making biofouling controls legally enforceable. The framework requires advance reporting, a vessel-specific Biofouling Management Plan, and detailed record keeping. It also mandates that antifouling coatings remain effective throughout their service life, and places additional requirements on vessels that remain in port for more than 45 days.

Inspections are carried out by the California State Lands Commission, which reviews roughly a quarter of vessels arriving each year. Penalties for non-compliance escalate quickly, from written violation notices to fines of up to $10,000 for repeated record-keeping failures.

This regulatory model highlights the direction of travel, while the IMO’s convention on biofouling may still be years away, jurisdictions like California are already setting enforceable standards. For shipowners, it’s a reminder that waiting for global rules is not an option, compliance with stringent regional requirements is already a reality.

Leading the way

Although it’s undeniable that the conversation around biofouling control has suffered from a lack of attention, some organizations have recognized its importance. The U.S. EPA’s Vessel Incidental Discharge Act (VIDA) is a national framework for the regulation of discharges incidental to the normal operation of a vessel, intended to prevent or reduce the discharge of contaminants from these vessels into U.S. waters, and to supplant the patchwork of existing federal, state and local requirements for the commercial vessel community.

At Cathelco, we understand the importance of acting fast. Our technologies are designed to tackle biofouling before signs even appear. Our Marine Growth Prevention System (MGPS) protects seawater pipework and cooling systems, preventing blockages before they fracture operations, meanwhile our USP DragGone also utilizes ultrasonic technology to prevent biofilm and hard fouling from attaching to hulls, reaching fuel savings of up to 13%.

Where to go from here

Even if the IMO’s framework will take time to come into fruition, that isn’t an excuse for vessel operators to stall in executing their own biofouling management strategies. Lower emissions, higher fuel savings and improved vessel performances are all capabilities that shipowners have been looking for, yet the solution remains unappreciated. It’s time to change perceptions and take a closer look at the merits of antifouling solutions.