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Granddaddy Tuna Caught Again After 13 Years On The Run

A bigeye tuna that was caught and tagged an astonishing 13 years ago as part of a scientific experiment has been re-captured at the grand age of at least 15 years old and a weight of 100 kg.

Caught 1000 km east of Fiji, the tag was found by crew member Samuela Ratini of Taiwanese vessel, San Sai FA No 12. The conventional yellow plastic dart tag was returned to scientists in Noumea who said it is remarkable that it was found very close to its release position.

Scientists say that 13 years on the run is close to a record period of freedom in the Secretariat of the Pacific Community’s (SPC) tuna-tagging program that was launched in the 1970’s, and in 2006 became the biggest tuna tagging operation in the world, with over 60,000 of 400,000 tagged fish having been re-captured.

At the age of maturity (about 3-4 years and weight 25 kg) in the Pacific Ocean bigeye spawning occurs mostly northeast of the Philippines. Female bigeye tuna can be weighing between 270 to 300 kg and may produce as many as 10 million eggs per spawning season. Bigeye tuna has an annual batch fecundity of 4 to 60 million eggs, but nevertheless the Pacific stock is of some concerns, especially due to the high taking of juveniles as by-catch in the FAD fisheries on skipjack tuna. Generally it is assumed that that bigeye have a lifespan of at least 12 years.

Bruno Leroy, a fisheries scientist with SPC said: “This is a great find. Recovering the tags is crucial to the success of our program because they provide information of growth, movements, natural mortality and fishing mortality of tuna, and helps us to estimate the status of tuna stocks and the impact of fishing.”

Tuna fishing is the biggest industry in the Pacific, providing employment to 10 million people living in the region as well as food and income, and is worth USD 5 billion per year. Bruno Leroy added: “This is the world’s biggest tuna fishery and Pacific countries have to manage the fisheries to keep them sustainable.”

With funding and operational support from Papua New Guinea, the French Global Environment Facility, Australia, the European Union, France, New Zealand, the United States, Korea, the Western and Central Pacific Fisheries Commission and Heinz Australia, the program has tagged fish in Indonesian waters to the west across to French Polynesia in the central Pacific.

SPC helps to train observers who are stationed on foreign vessels in the Pacific, where their job is to count, measure and identify all tuna taken by the vessel. The tag from the bigeye tuna was recorded by the onboard observer, Sitakio Semisi, from Tonga.