Foreign intelligence agencies are affixing sensor equipment to fish and turtles to steal sensitive maritime data, according to China’s Ministry of State Security.
In a social media post Friday, the MSS warned of a continuing “unseen covert war” beneath the waves, in which unnamed foreign spies were deploying buoys, “sensor-fitted marine animals,” wave gliders and shipborne electronic devices to Chinese-controlled waters.
Such equipment is being used to gather information such as the acoustic signatures of Chinese submarines, data on marine traffic, including naval vessels, and seabed topography, all of which, in the hands of an adversary, could pose “a serious threat to China’s national security,” MSS said.
In at least one incident, “spy turtles and spy fish” were found “to be equipped with sensors, swimming in a specific area to collect sensitive marine environmental data such as water temperature, salinity and ocean currents in real time, and then transmitting the data overseas via satellite.”
In another, “a new type of wave glider” propelled by ocean currents and powered by solar energy, was discovered in Chinese waters, transmitting “military-related marine environment and ship activity information to overseas regions.”
For years, China has been ramping up warnings about foreign espionage, urging citizens to be on the lookout for spies in all areas of their lives. Last July, MSS publicized a case in which a provincial government worker fell into a “meticulously designed honeytrap” while travelling overseas.
“Unable to resist the seductive beauty of the foreign intelligence agent,” Mr. Li was blackmailed with “intimate photos” into handing over official documents, MSS said. After his actions were discovered, he was sentenced to five years in prison for espionage.
Beijing is particularly sensitive when it comes to maritime security, with continuing disputes with multiple countries over the South China Sea, where it has built up reefs and islets into military bases.
In 2024, the MSS said it had detected underwater “lighthouses” in Chinese-controlled waters that could be used to guide foreign submarines and “pre-set the field for battle.” Since 2018, fishing vessels operating in coastal areas have been offered generous cash prizes for any spy devices they find and turn in to the authorities.
Friday’s warning comes amid renewed tensions between China and the Philippines over disputed territories in the South China Sea. Beijing has long blocked Manila from accessing reefs and islands, which a 2016 international ruling said belonged to the Philippines.
Speaking in Singapore last month, Philippine Defence Secretary Gilberto Teodoro said Manila would not accept any loss of “our territory and maritime rights, which we are mandated to defend, not only for us but for subsequent generations of Filipinos.”
China responded by sanctioning Mr. Teodoro, with the country’s Foreign Ministry saying he was barred from entering China, over his “erroneous remarks” which undermine “China’s legitimate interests and sabotages China-Philippines relations.”
While it is unclear whether MSS was referencing the Philippines in its latest claims about maritime spying, the use of marine mammals for espionage is not unheard of. In 2023, British intelligence said Russia had deployed trained dolphins to detect enemy divers near a sensitive base in the Black Sea.
“Imagery shows a near doubling of floating mammal pens in the harbour, which highly likely contain bottle-nosed dolphins,” the Ministry of Defence said. “In Arctic waters, the navy also uses Beluga whales and seals.”
An alleged Russian spy whale attracted global media coverage after he was spotted in Norwegian waters in 2019 wearing a camera harness with Russian labelling. Hvaldimir, as he was dubbed by locals, became something of a local celebrity for retrieving items people dropped into the water, before he was found dead in 2024, most likely killed after a stick lodged in his mouth prevented him from feeding properly.