The whale shark that knew it was being rescued (2)

It took thirty seconds for the diver to cut the whale shark free - during which time it lay completely still

The stunning underwater footage was filmed as part of the nature series called 'Secrets of Shark Island'

The heroic diver celebrates cutting the shark free from the rope wrapped around its body

The breathtaking moment was recorded in waters off Socorro Island, part of the Revillagigedo Archipelago, 200 miles off the coast of Mexico.

It was filmed as part of the nature series 'Secrets of Shark Island', which is being screened on the Smithsonian Channel.

Despite their colossal size, whale sharks are incredibly docile fish and pose little threat to humans.

They are the largest living fish on the planet and because they have long lives (estimates say they live over 70), mature late not producing offspring until over 30, and give birth to relatively few offspring during their lifetime, they are especially threatened by human exploitation.

Threats to the whale shark include fishing, habitat loss which results in loss of prey species, coastal development resulting in marine pollution, collision with boats, and disturbance or harassment by boats and divers engaged in irresponsible tourism activities.