Dwindling in numbers, whale sharks are protected in China - and black market salesmen are punished with hefty fines.

But when fisherman Cai Chengzhu, 48, spotted this 16-foot-long, two-tonne beast, he could not resist having a go.

He heaved it to shore and dragged it to the street.

Then, incredibly, he dumped it onto a truck - and drove it for half-an-hour to the nearest market.

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All in a day's work: Cai Chengzhu was fishing in Xianghzhi, eastern China, when he found this 16ft-long whale shark - before lugging it onto his tractor and driving it for half-an-hour to a market in nearby Shishi

Regulation states the valuable whale sharks, which can live for up to 100 years, should be set free immediately if caught.

But Cai, from Xianghzhi, in the far-eastern province of Fujian, admitted he planned to sell the creature from 10,000 to 20,000 yuan (around £1,000 to £2,000).

He claims the fish was already dead by the time they reached the market in Shishi, 10 miles away, after accidentally getting caught in his fishing net.

Trapped: The endangered mammal had broken into his fishing net and started eating all the fish he had caught

Despite strict laws against selling whale sharks, Cai could sell his (for £1,000) because it was already dead

He told local media he did not know it was a whale shark.

'The giant creature broke our net and got inside to eat the fish we caught,' he explained.

'As you can see it had eaten a fair few but after being trapped in the net, it had died.

Valuable: The enormous creatures can live for up to 100 years and weigh around 20 tonnes at full maturity

Fascinated: Passers-by were astounded to see Cai, 48, trundling through the village with the whale shark

'By the time we managed to free it, sadly it was too late.

'It was really unfortunate and we did our best to free it, but having caught it and because it was already dead, it seemed a shame to waste it.