Pew warns of fish aggregating device threat to bigeye tuna

Researchers from Pew Charitable Trusts have said that the already vulnerable stocks of bigeye tuna, widely used in sushi products, face a threat from weakly regulated fish aggregating devices (FADs) in the ocean.

These buoyed devices lure in large schools of fish, and often result in juveniles being caught before they have the chance to reproduce. According to the charity, the number of FADs in the ocean is unknown. The devices allow large fishing nets, known as purse seines, to catch huge quantities of fish at once, but often ensnare juveniles of endangered species, such as bigeye and yellowfin tuna.

Pew global tuna conservation programme officer Dave Gershman said: “FADs have increased the mortality of juvenile bigeye, so they’re being caught before they have a chance to reproduce and grow into adult fish. You can be dealing with 100 tonnes of tuna in that one school, so it’s difficult to separate out the fish by species.”

In 2016, Japan caught the most adult bigeye tuna, fishing up 12,610 metric tonnes. South Korea, Taiwan and China all followed, with the US ranking fifth.

Environmental groups such as Greenpeace have advocated for an outright ban on FADs.

Pew said it did not oppose their use, suggesting that they improve the efficiency of skipjack fishing and help those in the industry to provide more food quickly for consumers.

“Like with any other fishing gear, FADs need to be managed appropriately. And the international organisations … have been slow to look at the impacts of FADs and manage them appropriately,” said Gershman.

He also commented on Western and Central Pacific Fisheries Commission’s (WCPFC) temporary closure period to stop the deployment of FADs. The commission withdrew the ban after receiving encouraging data on bigeye tuna stocks last year. Gershman said the WCPFC ‘went too far in relaxing controls’ and ignored scientific advice calling for stricter catch limits. He suggested one solution could be limiting the number of times a fishing vessel is allowed to use FADs.

Since 2016, the United Nations proclaimed 2 May to be World Tuna Day in order to raise awareness of the global importance sustainable tuna fishing, and its associated challenges.

UN secretary-general deputy spokesperson Farhan Haq said: “The day seeks to recognise the critical role of tuna to food security, economic opportunity, and the livelihoods of people around the world. Tuna species account for 20% of the value of all marine capture fisheries and over 8% of all globally traded seafood, and as a result, the fish are threatened by an overwhelming demand.”

In January, tuna producer Princes Foods announced its aim to obtain all of its tuna from responsible sources by the end of 2019.