Binh Dinh fishermen in bumper catch

The off-season catch was sold for VND110,000 (US$4.84) per kilogramme.

Tran Quang Bao, captain of the boat, said tuna prices had increased by around VND12,000 (53 cents) per kilogramme since last month.

"The price is quite high and so fishing boats and their crews have high incomes. We are quickly stocking up on food and water to return to the sea."

According to the provincial Department of Agriculture and Rural Development, so far this year the fishermen have caught 8,511 tonnes of tuna, up 18.6% compared to the same period last year.

On average, a boat earns VND70-80 million (US$3,077-3,517) per trip.

Nguyen Viet Nghia, deputy director of the Institute for Seafood Research, said 485,600-502,900 tonnes of tuna are caught off central provinces every year.

The boats are mainly from Phu Yen, Khanh Hoa and Binh Dinh, and their catches comprise yellow fin tuna, big eye tuna and skipjack tuna, he said.

Binh Dinh was the first province to use new technologies and skills to supply fish to Japan, especially tuna.

By 2014 the province’s fishermen had modern equipment and technologies worth US$1 million to catch, preserve and transport tuna.

In September that year the first tuna was exported to Japan and sold at three times the price the fish fetches in the Vietnamese market.

The province has around 3,200 fishing boats.