Dolphins butchered for shark bait in illegal hunt off the coast of Peru

The dead dolphin, before being cut up and slaughtered. Credit: Jim Wickens/Ecostorm/ITV News

For more than a decade scientists and environmentalists have been warning of a mass slaughter of dolphins around Peru.

Hundreds of fishing boats have been accused of killing the animals and using their fatty bodies as bait to catch sharks.

The killings, as many as two or three per hunt, by hundreds of fishing boats around the country, add up each year to make it the biggest illegal slaughter of dolphins in the world, according to environmentalists.

ITV News has obtained footage that shows fishermen harpooning dolphins for bait. It's the first time this secret hunting has been filmed.

Science Editor Lawrence McGinty's report contains images you may find disturbing

The footage, shot undercover by British journalist Jim Wickens, shows the hunting taking place, hundreds of miles off the coast of Peru.

The dolphin is harpooned, brought on to the boat, then cut up and used as bait for shark fishing.

The carcass of the dolphin is then tossed over the side of the boat, and can often wash up on beaches in shores around Peru.

The dolphin meat is cut into strips and put on lines to catch sharks. Credit: Jim Wickens/Ecostorm/ITV News

Though illegal under Peruvian law, the slaughter is an "open secret" within fishing communities, according to marine conservation group Mundo Azul.

Previously there has been no evidence to support the claims made by environment groups, as fishing communities and officials denied it was going on.

Around 500 boats in involved in shark fishing, meaning as many as 10,000 dolphins could be hunted in this way, every year. Credit: Jim Wickens/Ecostorm/ITV News

Working undercover with Mundo Azul, British journalist Jim Wickens spent a week on board a shark fishing boat 100km off the coast of Peru, enduring rough seas and a near-death shipwreck incident in order to film the hunt.

The dolphin, once caught with the harpoon, bleeds heavily, attracting sharks. Credit: Jim Wickens/Ecostorm/ITV News

It is estimated that 500 boats are involved in shark fishing, which means as many as 10,000 dolphins could be hunted each year and used as bait. Journalist Jim Wickens, who filmed the footage, said:

The dolphin is hauled on to the ship, to be cut up. Credit: Jim Wickens/Ecostorm/ITV News

The practice of hunting is increasingly common as dolphin meat is a cheap alternative to other forms of bait.

Using dolphins in this way allows small scale fishermen, often poorly paid for their arduous work, to save money needed for fuel and other necessities.

The meat is also traded in exchange for petrol or fishing lines, according to a fisherman who previously took part in the hunt. Jose, not his real name, said a culture of secrecy surrounded the practice.

The meat is also traded between fishermen, illegally. Credit: Jim Wickens/Ecostorm/ITV News

Alison Wood from Whale and Dolphin Conservation said the practice was completely unnecessary, as well as inhumane.

Read: Fishing for secrets: My stormy mission to expose the 'world's biggest dolphin hunt'