Hundreds of fishing vessels – mainly Chinese – are reportedly switching off tracking systems to pillage fish from Argentinian waters.
The report, from environmental charity Oceana, suggests that the distant-water fleets are fishing for shortfin squid, a vital part of the diet of species such as tuna.
Oceana tracked vessels using Automatic Identification System (AIS) data from Global Fishing Watch, an independent nonprofit founded by Oceana in partnership with Google and SkyTruth.
AIS devices transmit information such as a vessel’s name, flag state and location.
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Oceana documented more than 6,000 "gap events", where AIS transmissions were interrupted for more than 24 hours, suggesting vessels may have disabled tracking devices.
These vessels were invisible for more than 600,000 total hours, hiding fishing vessel locations and masking potentially illegal behaviour such as crossing into Argentina’s national waters to fish.
The Chinese fleet was responsible for 66% of these incidents.
Beth Lowell, Oceana’s deputy vice president of US campaigns, said: “Illegal, unreported, and unregulated (IUU) fishing threatens the health of the oceans. The vessels that disappear along the edge of the national waters of Argentina could be pillaging its waters illegally.
“IUU fishing is wreaking havoc on our oceans, coastal communities, and people who depend on the oceans for their livelihoods.
“A recent study found the United States imported an estimated $2.4bn [1.7bn] worth of seafood derived from IUU fishing in 2019."
She added: “The United States can take action to address IUU fishing by requiring that all seafood imports have catch documentation to demonstrate it was legally caught, implementing full-chain traceability, and making transparency a condition of import.
“AIS, when used continuously, can provide managers, governments, and the public more visibility of what is happening beyond the horizon and deter illegal activity.
“The United States and all governments should take action to ensure all seafood is safe, legally caught, responsibly sourced, and honestly labeled.”
The South China Morning Post reported that in recent months, hundreds of Chinese boats had clustered around countries such as Argentina and Ecuador.
Vessels have been criticised and have also had run-ins with local authorities, it reported.
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