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A land girt by sea could be particularly vulnerable to grey-zone warfare tactics designed to break the ecosystem or civilian relationship with that sea.
With that in mind, Australia should be asking the question whether that relationship can be abused by adversaries to create a dual ecological and strategic problem.
Australia could be vulnerable to an adversary stationing a large but not military, distant-water fishing fleet operating just outside Australia’s 200-nautical mile exclusive economic zone (EEZ) and utilising grey-zone warfare tactics to economically cripple the country’s migratory fish stocks on an industrial scale.
For this example, we use the People’s Republic of China’s (PRC) global fishing fleet. China’s global fishing footprint could number as many as 57,000 industrial fishing vessels and account for more than 44 per cent of the world’s visible fishing activity between 2022 and 2024, according to non-profit ocean conservation organisation Oceana.
To legally station such a civilian armada off Australia’s northern approaches or even along its coastal areas could have profound consequences for the economy and even Australia’s national spirit, which is tied to the fishing ecosystem, beaches and national icons, such as the Great Barrier Reef.
These vessels can legally target tuna, billfish, mackerel and shark species that routinely cross between Australian waters and the high seas. While Australia’s fishing sector is among the most sustainably managed globally, no management system can withstand a heavily concentrated foreign fleet removing enormous volumes of fish the moment they move beyond our jurisdiction.
“It is critical that we have eyes on the seas, paying close attention to the world’s largest fishing fleets, especially from China, which have been linked to illegal, unreported, and unregulated fishing and human rights abuses at sea. The sheer scale of China’s distant-water fleet has a profound impact on marine ecosystems worldwide,” said Dr Max Valentine, Oceana illegal fishing and transparency campaign director and senior scientist.
“Transparency at sea is essential, not just to track distant-water fleets, but to hold bad actors accountable, protect vulnerable communities, and safeguard the sustainability of our ocean for future generations.
“To protect our oceans and fisheries, we must know who is fishing and where.”
Oceana’s analysis of China’s apparent fishing activity over a three-year period from January 2022 to December 2024 reportedly showed that 57,000 fishing vessels, primarily trawlers, flagged to China, appeared to fish for more than 110 million hours during the recorded period.
China’s fishing vessels were most active in South Korea (11.8 million hours), Taiwan (4.4 million hours), Japan (1.5 million hours), Kiribati (almost 425,000 hours), and Papua New Guinea (over 415,000 hours), according to the NGO.
A commercially focused fishing blockade is almost-certainly a cost-effective solution for the PRC to achieve hidden strategy goals. Fishing vessels are considered to be civilian, not military assets, and can bypass traditional military monitoring and law enforcement.
Australia is already struggling to address challenges associated with its oceanic boundaries. The country has suffered a sudden panic attack when Peoples Liberation Army-Navy Task Group 107 transited through international waters and conducted a live-firing exercise off in Australia’s exclusive economic zone off Tasmania in February this year.
Another taskforce is already potentially making its way south with a Chinese naval flotilla involving a frigate, destroyer, landing helicopter dock ship and replenishment vessel, monitored by the Australian Defence Force, making its way through the Philippines earlier this month.
In respect to readiness, other nations, particularly in South America, can offer cautionary tales to learn from.
Argentina has regularly faced annual confrontations with huge swarms of Chinese squid-jigging vessels gathering just outside its EEZ. At times, the Argentine Navy has allegedly intercepted and blocked hundreds of Chinese fishing vessels operating near their boundary line, switching off their transponders, slipping into Argentine waters under cover of darkness and overwhelming local fish stocks. The Argentine government has deployed its navy, fired warning shots and even seized vessels in a dramatic illustration of how quickly an ecological dispute can escalate into a security crisis.
Peru has encountered similar pressures. During multiple seasons, a vast Chinese fleet has parked along the edge of Peru’s rich Humboldt Current System, targeting migratory squid and pelagic species that sustain local coastal communities. Peruvian authorities have repeatedly warned that the fleet’s intense, prolonged presence just outside their waters risks undermining national conservation efforts and destabilising regional marine ecosystems.
These episodes show how legal loopholes and sheer scale enable China’s fleet to operate with near-impunity while draining the resources neighbouring nations depend on.
They also reveal how difficult monitoring becomes when hundreds of foreign vessels cluster near an EEZ boundary, engaging in transponder “dark” operations and exploiting the ambiguity of high seas fishing rules.
Final thoughts
For Australia, the message is clear: that even without a single breach of our maritime borders, the ecological and cultural damage could still be severe.
The Australian government has traditionally struggled around other boating predicaments, such as the controversy surrounding the continued passage of asylum seeker vessels to the country, and it would need an overhaul of stronger high seas governance mechanisms, expanded satellite and aerial surveillance, deeper cooperation with Pacific partners, and a diplomatic approach that treats fisheries depletion as both an environmental and strategic challenge.
Australia cannot stop foreign fleets from fishing in international waters. But it can learn from other international examples, such as Argentina and Peru, to recognise that in the future, the lines may blur between commercial deception and military strategy.
