An Iranian fisherman has been filmed 'surfing' on top of a huge whale shark in the Persian Gulf prompting criticism from a scientist who branded the stunt "not very clever".

The video surfaced on Instagram in early July. It depicts the fisherman, known only as Rahmat, easing himself onto the animal as it swims alongside his boat just below the water's surface.

The young man seamlessly transfers his weight onto the large fish, which does not seem to resist his company, and travels for around 20 metres at a sedentary pace.

The clip provoked anger from internet users while others pointed out that the opportunistic surfer had not actually harmed the animal.

France 24 Observers spoke to Maryam Mirzaloo, an Iranian researcher in paleoceanography about her fellow countryman's feat.

She said: "The animal we see in the video is not a whale, as the surfers originally thought, but rather a whale shark. They eat plankton and small fish, and live mainly in areas such as the Persian Gulf, the Gulf of Oman, off India, Australia, or the Philippines.

"They are very friendly fish, and many divers manage to approach them because they do not fear human presence. They can be up to 13 meters long, and weigh up to 30 tons, but it is obvious that it is not very clever to climb on them.

"Keep in mind that animals should not be touched in their natural environment. There are rules on how to approach whale sharks and how to preserve their habitat.

"Even though the man did not want to hurt the animal, it could have caused a stressful situation that disorientated it and that is not good for its health," she added.

The whale shark is classified as a vulnerable species. There are approximately 10,000 left in the world's seas and oceans.

Whale shark surfing
The fisherman demonstrated excellent balanceScreengrab / Youtube