China claims foreign agencies use 'spy turtles' and 'spy fish' in underwater espionage

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China's Ministry of State Security has claimed that foreign intelligence agencies are using marine animals fitted with sensors, including "spy turtles" and "spy fish," to collect sensitive data in Chinese waters as part of what it called an "invisible secret war. " In a post on the WeChat social media platform on Friday, the ministry said large marine animals had been found "attached to sensors" while swimming in Chinese waters. The animals were collecting real-time data on water temperature, salinity and ocean currents and transmitting it overseas via satellite, the ministry claimed. The ministry did not provide specifics about where the animals had been found or which nations it suspected of overseeing the alleged espionage.

Devices can act as 'sentries' or 'lighthouses'

The ministry said foreign spy agencies had for years tried to analyse Chinese naval activities, create underwater maps of the country's maritime coastline and monitor its offshore oil and gas deposits. It described several categories of "maritime spies." Some act as underwater "sentries," lurking on the seabed for extended periods to collect hydrographic information and data on vessel activity. Others function as drifting "secret agents" that move with ocean currents. A third category acts as underwater "lighthouses," which the ministry claimed could guide foreign submarines through Chinese waters while concealing their movements. The ministry also said it had found buoys deployed by an overseas marine research institute equipped with meteorological sensors capable of tracking the acoustic signatures of Chinese submarines in real time. It also cited a new type of "wave glider" powered by wave motion and solar energy, which it said was transmitting military-related maritime environmental data and information on vessel activities.

Technical characteristics outlined

National security agencies said the devices share three characteristics: advanced technical performance allowing long-term automatic operation or remote control; complex and powerful functions including data storage, analysis and transmission; and a high degree of equipment integration with self-destruct mechanisms that activate after completing their missions. The government offers financial rewards to fishermen who discover suspected spying equipment in national waters. Incentives reportedly range from 50,000 to 500,000 yuan (£5,500 to £55,000), depending on the significance of the find.

Similar claims made in the past

China regularly makes claims of espionage efforts taking place in nearby waters including the South China Sea, the East China Sea and the Taiwan Strait, which are among the most militarily sensitive and heavily contested waterways in the world. In 2024, China said it had identified "lighthouses" hidden on the ocean floor that could guide the transit of foreign submarines and "pre-set the field for battle." Allegations of marine animals being used for military purposes are not new. In 2023, British intelligence said Russia was stepping up security at its Sevastopol Black Sea fleet base by deploying trained bottlenose dolphins to counter enemy divers. In 2019, a beluga whale turned up on the Norwegian coast wearing a harness that appeared to have a mount for a small camera, sparking speculation that it had been trained to spy for the Russian navy. Moscow never issued an official response. As with previous statements from Beijing, no external agencies have confirmed the existence or use of animal-mounted tracking systems in Chinese waters.