Giant 7ft tuna fish spotted in a British river 30 miles from the sea is so big its finders first thought it was a cow

This was the extraordinary moment a 7ft long tuna fish was spotted in a British river 30 miles from the sea.

The huge tuna – which are usually found in oceans – was found washed up on the banks of the River Severn as experts have said it may have been chasing salmon upstream.

Kevin Brady, 33, was paddle boarding with friends Steve Burgess and Alec Foster when they came across the dead fish near to the village of Minsterworth in Gloucestershire.

He said: ‘Steve spotted it on his jetski and came to myself and Alec Foster on paddle boards shouting, “I’ve found a 7ft fish”.

‘We didn’t believe him, thinking it must have been a cow or something. It wasn’t until we got right up next to it we realised it was a fish.’

The adventurer, who took a month to swim the 220-mile River Severn last year, showed off the rare sighting on social media.

It had been washed up onto the side of the river, which is better known for salmon and elvers.

Dai Francis, of the Severn and Wye Smokery, said the giant fish may also have been tempted in to British waters by rising temperatures.

He said: ‘This last week we have had some massive tides so it’s probably followed the salmon and everything else up the river.

‘You do not usually get tuna in British waters but as the water temperature increases, they are getting spotted more and more.

‘The water temperature in the River Severn is about 17C, which is really warm for this time of year.

‘That means all the fish from the West coast of France, the Bay of Biscay for instance, come around the corner and into the Bristol Channel.’

He added: ‘Basically the big fish follow the smaller fish and climate change means they come in further.’

The World Wildlife Fund’s website claims if the tuna fish was a car, it would be the Ferrari of the ocean world as they are sleek, powerful, and speedy.

There are 14 species of tuna, but the Atlantic bluefin can reach 10ft in length and weigh as much as 1,500 lbs, more than a horse, and can swim up to 43 miles per hour across long distances.

The WWF website says: ‘Some tuna are born in the Gulf of Mexico, cross the entire Atlantic Ocean to feed off coast of Europe, and then swim all the way back to the Gulf to breed.’

Large bluefin catches can sell for as much as £1million in Japan, where a single 500lb fish could make 10,000 servings of sushi.

Bluefin tuna are rarely seen in the English Channel although they were once common in the Mediterranean and Atlantic.

Expert Mr Francis said in years gone by North-East ports were known for excellent tuna fishing, and the rich would go there on their yachts to try and catch the species that are now more likely to be found in a can.

He said although the fish in the Severn looked like a whopper, it was probably not close in size to a 526lb tuna once reportedly caught off the coast of Scarborough.