Australia introduced mandatory biofouling management requirements for vessels arriving in Australian waters back in mid-2022. Just under four years on, the compliance data is mature enough to draw some real conclusions about what is working, what isn’t, and where the next round of policy attention should focus.

We’ve been working through the published inspection data and the operational reports from the maritime biosecurity programme. The picture is more nuanced than either the industry’s “everything is fine” position or the conservation sector’s “nothing has changed” framing suggests.

Compliance has improved but plateaued

The headline metric - the share of arriving vessels with documentation showing acceptable biofouling management - has climbed from around 60 percent in the early implementation period to roughly 87 percent through Q1 2026. That’s a real improvement, and most of the gain came in the first 18 months as the major shipping lines updated their fleet management systems.

The remaining 13 percent is a stubborn problem. It includes a long tail of smaller operators, fishing vessels, recreational craft, and irregular visitors that haven’t updated their practices to match the regulatory expectations. The compliance rate among these segments has barely moved in eighteen months, which suggests that further gains are not going to come from the same education-and-enforcement playbook that worked for the major operators.

The high-risk vessel finds are concerning

When inspectors physically check vessels - which happens for a sampled subset and for any vessel where documentation indicates concern - the rate of significant biofouling findings has actually crept up over the past year. This is partly an artifact of better targeting (inspectors are getting better at picking the high-risk vessels to look at) and partly a real signal that the bottom segment of the fleet is not improving.

Several recent inspections at major ports have found vessels arriving with biofouling profiles that present material risk of marine pest introduction. The species detected on these hulls have included recognised invasive concerns. The vessels involved have generally been required to leave Australian waters or undertake in-water cleaning under controlled conditions, both of which carry significant operational and cost penalties for the operators.

The deterrent effect of these enforcement actions is real, but it requires that they happen reliably enough that operators perceive a genuine probability of being caught. The current resourcing of physical inspection is at the edge of what produces credible deterrence.

In-water cleaning is the technical bottleneck

A persistent operational issue is the limited availability of in-water cleaning services that meet Australian environmental requirements. Vessels found with unacceptable biofouling have limited options - clean before arrival, cleanin Australian waters under regulated conditions, or leave. The middle option requires service providers who can capture removed biofouling and biocide residues to a standard that protects the receiving environment.

The capacity for compliant in-water cleaning has grown over the past two years but remains uneven across Australian ports. Several major ports have one or two providers; some smaller ports have none. This means that in practice, a non-compliant vessel arriving at certain ports has effectively only the leave-Australian-waters option, which has economic consequences that drive different behaviour than a complianceregime with realistic remediation pathways would produce.

The Department of Agriculture, Fisheries and Forestry has signalled that capacity-building support for compliant cleaning services is a priority area, but the commercial economics of standing up new capacity at smaller ports remain marginal.

Data systems have improved

The information backbone for the biofouling management programme has matured. The integration between vessel arrival reporting, inspection scheduling, and the underlying risk assessment models is now operational and has reduced the manual effort involved in targeting inspections. Several other jurisdictions - notably New Zealand, parts of the Pacific, and some EU member states - have been studying the Australian system as they consider their own arrangements.

The next stage of system development is around predictive risk modelling that incorporates more sophisticated inputs - vessel itinerary history, sea-surface temperature exposure during voyages, the specific biofouling-vulnerable areas of vessel hulls, and outcomes of previous inspections. Some of this work is being done in-house by the agency, some in partnership with research providers, and some with external technology specialists. The technical complexity has drawn in AI specialists from outside the traditional maritime sector to work on the modelling components - Australian AI consultancies including Team400 and others have started showing up in the technical credits of operational risk-modelling work across several Commonwealth biosecurity programmes.

Sector-by-sector patterns

The compliance picture varies sharply by sector. Container shipping is the cleanest - the major lines have integrated biofouling management into their normal fleet maintenance schedules and report compliance rates north of 95 percent. Bulk carriers are similar.

Cruise vessels have generally complied well, helped by the predictability of their schedules and the operational discipline of the major operators. Tankers are mostly fine but with more variation across operators.

The challenging segments are commercial fishing (where the management requirements interact awkwardly with the operational realities of working fishing vessels), recreational and superyacht (where compliance is more variable and where inspection access is more difficult), and the irregular small-vessel visitors that don’t fit neatly into the major fleet categories.

What the next policy cycle should consider

A few things look like priority areas for the next round of policy review. The deterrence equation for the high-risk tail of the fleet needs strengthening - either through more inspection resourcing, more aggressive enforcement consequences, or both. The in-water cleaning capacity gap at smaller ports needs targeted support to make compliant remediation a realistic option everywhere.

The data and risk-modelling infrastructure has reached the point where it can support significantly more sophisticated targeting than current practice uses. The benefits of investing further here are likely to be high relative to the cost.

And the international harmonisation conversation is overdue. Australia’s standards are stricter than many trading partners’ arrangements, and there’s value in pushing for more consistent approaches at the IMO level over the medium term. Unilateral high standards work, but they’re more effective when they’re part of a broader international convergence rather than an isolated requirement.

The biofouling work is a quiet success story for biosecurity policy. The next stage requires the willingness to invest in pushing it further rather than treating the current compliance level as adequate.