The dark truth behind supermarket tuna

The FT connected abuses in some of these fleets to UK supermarket shelves using fishery details provided by retailers, data from the Ocean Disclosure Project — where companies voluntarily publish seafood sources — research into products in supermarkets, publicly available paperwork and interviews with workers.

One of the Chinese longline fisheries where workers reported abuses has been used by Wm Morrison, Tesco and Waitrose, while the other has supplied Morrisons, Asda, J Sainsbury and Tesco.

The supermarkets said they are urgently looking into the claims. Sainsbury’s added it had not sourced any own-brand products from Chinese or Taiwanese vessels for the last three years.

“Retailers are committed to upholding high standards of welfare for all people who work in their supply chains, and these allegations must be swiftly investigated,” said Sophie De Salis, sustainability policy adviser for the British Retail Consortium.

She added that although supermarkets are already working with external organisations to improve standards, they also want human rights and environmental due diligence to be made mandatory by the government to ensure an equal playing field.

China’s department of agriculture said it takes any allegations regarding its vessels seriously and is planning to investigate the claims. The country “resolutely opposes any form of forced labor” and has “strict regulatory requirements for the employment of crew members by fishing enterprises”, it added.

The South Korean longline fishery containing vessels spending extended periods of time at sea without visiting port is used by seven UK retailers, including Marks and Spencer.

Kang Dong-yang, a director at South Korea’s ministry of oceans and fisheries, said measures are being taken to improve conditions. These include ensuring a minimum of six hours’ consecutive rest each day and a period of port leave every 12 months. From next year, fishermen will receive a two-month break every 10 months, he added, with punishment for vessels violating rules.

Dongwon Industries, owner of the South Korean vessels, said it already guarantees crews six hours’ consecutive rest and five days’ annual port leave. Two of its vessels tracked by the FT have recently been sold, the company added.

The owners of Bunanda’s purse seine vessel said they “deeply regret” his health issues but denied they provided inadequate medical care or delayed treatment. They also said he was advised to seek medical attention before departure but declined. “The company acted strictly according to medical advice and regulatory compliance,” the owners added, paying for all costs related to his medical treatment and repatriation. They also denied he had his ID taken and said the payment of wages and fees were the responsibility of his Indonesian recruitment company. “The company remains committed to upholding human rights and social responsibility in overseas fisheries,” they added.

Taiwan’s Fisheries Agency said an investigation into the case concluded that there was no evidence delayed medical treatment led to Bunanda’s paralysis. There was also no evidence he was charged recruitment fees, that he was made to take out a loan, that he was misled about pay or that he had his ID taken.

Beyond certification

While international conventions on workers’ rights exist, enforcement is weak and major fishing nations — including China, Taiwan, South Korea, and the US — have yet to sign. The ILO, the UK and France want all countries with fishing fleets to ratify an ILO convention guaranteeing rights. Indonesia has committed to sign in 2026, and South Korea has indicated a phased introduction. New ILO guidelines for migrant fishermen were agreed at a meeting last month.

But rights groups say action can already be taken without such agreements — if existing international and national laws are enforced. Flag states, already legally responsible for vessel conditions, should ensure protections for migrant crews; home countries of migrant workers should tackle abusive recruiters; coastal states overseeing fisheries should monitor and deny access to offending vessels; and port states should inspect ships and hold violators accountable.

Consumer markets should also tighten port checks to stop seafood linked to forced labour from reaching consumers. Broader use of electronic and satellite monitoring would also strengthen enforcement and transparency, they say.