Moscow: President Vladimir Putin’s opponents on Monday gleefully sought to prove the Russian strongman had massively exaggerated the weight of a pike he caught on a recent fishing expedition to Siberia.

The Kremlin on Friday had announced that Putin managed to catch a 21 kilogramme pike while on a trip to the region of Tuva, providing television footage and pictures of the president stripped to the waist as he cast his line.

The images were clearly aimed at proving that Putin at the age of 60 is still comfortable in raw nature and has the physical energy to catch a huge fish and lead his nation in changing times.

But the catch immediately sent the opposition — whose scrutiny on the internet of Putin’s stunts becomes ever more thorough each year — scurrying to their fishing manuals to prove the Kremlin wrong.

And prominent opposition bloggers claimed on Monday that Putin had fallen into the classic amateur fisherman’s trap of exaggerating the size of his catch.

Blogger and author Alfred Kokh calculated the length, diameter and volume of the fish and said it could only have weighed “10-11 kilogrammes” and not the 21 kilogrammes as claimed by the Kremlin.

Pro-opposition journalist Oleg Kashin added that a fish weighing 21 kilos and the size of the one caught by Putin would be so dense that it would simply have sunk to the bottom of the lake.

“A pike that heavy just could not swim,” Kashin wrote on Twitter. “She would sink to the bottom! In fact this pike was made from granite.”

Putin’s spokesman Dmitry Peskov rubbished the claims, which he blamed on “it being summer, there’s nothing to do, people need to talk”.

“I personally saw the scales and was present at the weighing. The pike really weighed more than 20 kilogrammes,” he told the Russian News Service.

The opposition Novaya Gazeta newspaper meanwhile asked why it had taken the Kremlin until Friday to release the images from a trip that appeared to have taken place over the July 20-21 weekend.

“Maybe they had to agree the weight of the pike themselves? Maybe they also had to weigh up the possible propagandistic effect, a plus or a minus?” the paper wrote.

The footage was loaded with political symbolism, with Prime Minister Dmitry Medvedev popping up on the excursion to take pictures and even sample the grilled pike in what seemed a bid to lay to rest rumours of a split with Putin.

Some bloggers alleged that the man who caught the fish was not Putin but a double or that the footage dated from a past trip to Tuva in 2007 given the president seemed to be wearing the same watch and clothes.

“The clothes are not old clothes, they are new clothes,” said Peskov. “As for the watch, it is the same one as he wore then,” he acknowledged.

The pro-Kremlin mass-circulation daily Komsomolskaya Pravda showed no such suspicions, devoting a whole page to pictures of Putin in his camouflage outfit and fawning commentary.

“Many people think that catching such a trophy is a pure accident,” a fishing expert named Vitaly Maximov told the newspaper.

“Be sure, it’s not by chance! You need to have the psychology of a victor and a risk-taker.”

The stand-off between pro-Kremlin media and bloggers recalls a similar controversy last year when Putin took to a hang-glider to fly with endangered cranes on their migration.

It later emerged that the cranes had failed to migrate and had ended up being transported by plane to fenced enclosures in nature reserves.

In a widely ridiculed stunt in 2011, Putin “discovered” ancient Grecian urns while diving in the Black Sea but the Kremlin later admitted the treasure had been placed in shallow waters for him to find.