About 2,000 crew members withdrew labour over pay and conditions, as well as citing serious breaches of overfishing rules by Spanish and French companies.

The waters of west Africa and the Indian Ocean boast some of the world’s largest, healthiest populations of tropical tuna, and that makes them havens for industrial tuna fishing fleets, owned by countries vastly richer than the nations whose borders form these coastlines.

In order to protect the fish populations of poorer African nations from rapacious overfishing by richer countries, EU tuna vessels are bound by agreements centred on the sustainability and “social empowerment” of third countries. Last week, however, in an unprecedented action involving 64 vessels and roughly 2,000 crew from Senegal and Ivory Coast, 80% of the EU fleet in the Gulf of Guinea and the Indian Ocean went on strike.

Not only were they protesting over poor pay and working conditions in one of the world’s most dangerous jobs, they also said the agreements from the EU aren’t worth the paper they’re printed on. They accused the EU fleet of unsustainable practices, and urged the EU commission to listen to NGOs and investigate.

Some fishers from Senegal and Ivory Coast employed on French and Spanish-owned vessels are paid as little as $219 (£174) a month, or $54 (£42) a week, according to the International Transport Workers’ Federation (ITF), which backed the strike. Their wages, far less than the monthly minimum of $658 (£522) set by the International Labour Organisation (ILO), contravene longstanding agreements between the EU commission and African countries to promote sustainable fishing and employment, unions said. These agreements, which represent up to €5m (£4.2m) a year, are “massively lucrative” for the French and Spanish firms whose vessels are licensed to fish tuna in African waters, according to the federation.

Johnny Hansen, the chair of the ITF’s fisheries sector, said: “It beggars belief that superprofitable companies and the government authorities, benefiting from highly advantageous fishing agreements negotiated for them by the EU commission, think it is acceptable to disregard the clear provision for the ILO seafarers’ basic minimum wage.”

Yoro Kane, the general secretary of the fishers’ union UDTS, Senegal, said the agreements between the EU commission and African countries are “massively lucrative for the French and Spanish firms whose vessels are licensed to fish for tuna”, but the ILO minimum salary of $658 is not being observed, with some paid a third of that figure.

Opagac, a Spanish organisation representing producers of frozen tuna, denied claims crew are paid less than the ILO minimum or that any breach of fisheries agreements, known as sustainable fisheries partnership agreements (SFPA), had taken place. The fishers have told unions that the EU vessels are under-reporting catch in order to reduce crew’s catch bonuses, and that fishing observers, the “eyes and ears” of vessels responsible for checking catch data, are absent. These requirements also form part of the SFPAs.

Stocks of the tropical tuna species yellowfin and bigeye are overfished in the Indian Ocean, where the EU fleet harvests a third of tropical tuna. The four-day strike has been suspended pending a proposal brokered by the Senegalese and Ivory Coast authorities.

A letter to Ivory Coast’s director general for maritime affairs, sent by a lawyer for the fishers and UMPCI and SYMAPECI unions for the Ivory Coast fishers, said the strike was lifted after a proposal to pay intermediate monthly salaries equivalent to £390 to the crew, plus bonuses. Dated 8 June, the letter said that some fishers had been arrested and imprisoned, and called for their release. A settlement needed to be agreed within 15 days, to “calm tensions”, it said. The interim payment was agreed on the understanding that substantive negotiations on payment of the ILO minimum would begin with employers within three weeks.

Alfonso Daniels, the author of a report by the Financial Transparency Coalition that named the huge Spanish tuna company Albacora SA as among the world’s top 10 companies involved in alleged IUU (illegal, unreported and unregulated) fishing, said: “There are grounds to believe these companies are not acting sustainably, and now there are concerns over labour rights. The EU, having signed these agreements, should investigate these companies.”

An EU Commission official said fishers are entitled to the ILO minimum wage but the definition of basic salary differs from country to country, in particular in relation to bonuses. ILO guidance refers to national laws to rule the matter, the official said, adding that the commission is “following closely the strike affecting some EU vessels”, and will “strongly push” for working groups to address issues concerning fishers’ pay and conditions.

Julio Morón, managing director of Opagac, which represents Albacora, Nicra and Petusa, three Spanish companies owning vessels operating under SFPA sustainable agreements, said the EU tuna fleet “strictly complies with national and international legislation, and all sailors earn more than the ILO minimum wage.” He denied accusations of non-compliance with fisheries agreements. He added: “A period of six months of negotiation has been opened between African employers and unions that we hope can be resolved in a positive way for all.” The ITF union has submitted the fishers’ wider concerns to a body responsible for a review of the SFPA between the EU and Ivory Coast in 2024, with the hope they can be addressed by French and Spanish vessels before the signing of any agreement.