Scientists working with the Australian Antarctic Program have tested an environmental DNA approach that could strengthen biosecurity efforts aimed at keeping invasive marine species out of sub Antarctic islands and Antarctic waters. Biofouling organisms can travel unnoticed on vessel hulls, and once a non native species establishes in a cold adapted ecosystem, eradication is often unrealistic. The research is positioned as a practical monitoring tool that can complement existing procedures such as hull cleaning and visual inspections.

 

How eDNA Turns Seawater Into a Species Checklist

 

Environmental DNA refers to genetic material shed by organisms into their surroundings through cells, waste, and tissue fragments. By collecting water samples and analysing the DNA they contain, researchers can infer which organisms have been present in the local environment or have recently passed through it. In this study, the team applied a DNA barcoding method to match the recovered genetic signatures to known species, allowing a rapid scan for potential biofouling hitchhikers without relying only on what divers can see.

 

Field Trial on a Voyage to Macquarie Island

 

The trial was carried out during a 2022 voyage from Tasmania to sub Antarctic Macquarie Island aboard MPOV Aiviq. The sampling design focused on capturing a before and after picture around hull cleaning, with seawater collected in Hobart prior to cleaning and then again during and after the cleaning process. The team also sampled alongside the vessel at Macquarie Island to test whether hull associated species could be detected as the ship entered a highly sensitive environment.

 

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A Simple Sampling Method with a High Detection Payoff

 

To capture eDNA, researchers used small sponges placed inside perforated plastic balls, allowing seawater to flow through and deposit genetic material onto the sponge surface. This low complexity approach is important in polar operations where equipment must be robust, easy to deploy, and repeatable across voyages. The method aims to produce a consistent sampling routine that can be built into standard biosecurity checks without requiring extensive additional ship time.

 

Comparing eDNA Results with Diver Inspections

 

Divers conducted visual surveys of the hull so that eDNA detections could be compared against what was physically observed. The results showed a clear difference in sensitivity. A visual survey identified 24 species, while eDNA analysis detected 41, spanning groups such as worms, sea stars, molluscs, sponges, algae, crabs, and sea squirts. When sampling was conducted at Macquarie Island, 27 hull associated species were detected, and 14 of these had previously been visually identified in Hobart, suggesting the technique can track signals that align with known biofouling presence.

 

What the Data Can and Cannot Prove

 

The researchers stress that a positive eDNA detection does not automatically confirm that live organisms are being transported, because dead organisms can still shed DNA that remains detectable. That limitation matters for biosecurity decisions, because management responses depend on whether a species is alive, viable, and capable of establishing. The study’s framing is that eDNA works best as an early warning and validation tool that can guide follow up actions such as targeted visual checks, additional sampling, and risk assessment rather than serving as a standalone proof of live transfer.

 

Why This Matters More as Access Increases

 

Sub Antarctic islands and Antarctica are often described as among the few remaining marine regions without confirmed established non native species populations. That status is under pressure as vessel visitation rises and ocean conditions change. The research argues that improved monitoring tools are needed to verify whether biofouling controls are working and to build baseline datasets that help detect changes over time. The team has continued to collect eDNA samples during later voyages, including work linked to Denman Glacier and Heard Island, adding data that could support future environmental monitoring programs and more defensible biofouling management standards.