SEAWORLD has long battled claims about the conditions its captive killer whales are kept in, including allegations they suffer such acute stress they become ill, aggressive and die early.

This week it came under fire again after TripAdvisor announced it would no longer sell tickets to SeaWorld and other parks that breed, import or capture whales, dolphins and porpoises.

10 One of SeaWorld's star attractions is their killer whale shows Credit: Copyright 2017 The Associated Press. All rights reserved.

The travel website's announcement comes shortly after Virgin Holidays' decision to do the same.

It's incredibly welcome news for many, who argue the 36ft pools the killer whales are kept in are inhumane.

Former SeaWorld trainers John Hargrove and Jeffrey Ventre agree and have told The Sun Online that is just the tip of the iceberg.

They claim whales at the popular theme parks were routinely drugged and deprived of food and even self-harmed as a result of the psychological trauma they suffered.

Jaw-popping and self-mutilation

Jeffrey Ventre, now 55, was initially delighted when he landed the role of SeaWorld trainer in 1987, saying: “My day to day activities were performing for the public and taking care of whales and dolphins.

"I was initially happy as it's pretty hard to do because so many wanted to be trainers, and I felt honoured to be working with marine mammals."

10 Jeffrey Ventre was one of SeaWorld's killer whale trainers Credit: Jeffrey Ventre

However, over the next eight years, he discovered the horrifying truth.

He says: “The job is more akin to a stunt man or clown performing with captive animals using food deprivation as a motivator."

Jeffrey came to notice the whales displayed signs of extreme distress.

They would grind their teeth or chew concrete out of boredom, causing dental damage, and "raking" - scratching each other with their teeth - was common.

He says: “There was a lot of self-mutilation. Jaw popping was regularly seen - it's a threat display between two orcas."

Jeffrey claims the whales were medicated daily for medical conditions - but also to control their behaviour.

10 Orcas at SeaWorld San Antonio. PETA claims it shows one orca who has holes drilled into the pulp cavities its broken or worn teeth in order to prevent infection, while the other orca has a completely collapsed dorsal fin. Credit: PETA

“The whales and dolphins were stressed and this caused stomach ulcers," he explains.

"So they got meds for that. They also got chronic infections, so they got antibiotics. They were also sometimes aggressive or hard to control so they could be given Valium to calm their aggression.

“All whales were getting vitamins packed in their fish. Several got daily antibiotics, including Tilikum, for chronic teeth infections.”

Inbreeding was also common, with John recalling a whale called Taku - Tilikum's son - mating with his own mother.

10 Jeffrey worked at SeaWorld Orlando for years before becoming a whistle blower Credit: YouTube

John began his killer whale training in 1993, when he was 20, and resigned in 2012.

He remains deeply affected by what he saw, explaining captivity cut the whales' lives short.

He adds: "I worked with some whales that were on medication every day of their life and have personally watched whales die at very young ages from disease.

“It was the most difficult decision in my life to have to walk away from the whales I loved to be able to become a whistle-blower and expose the industry."

10 Jeffrey Ventre worked at SeaWorld, and has since spoken out about their practices

Killed and dismembered

SeaWorld killer whale Tilikum was connected to the death of three people, and he became the focus of 2013 documentary Blackfish.

On February 24 2010 trainer Dawn Brancheau, 40, who had worked at SeaWorld for 16 years, died at the Orlando park after Tilikum pulled her into the water by her ponytail.

She suffered “multiple traumatic injuries” and was held under the water until she drowned.

John was devastated by her death.

He says: "I was personal friend with Dawn Brancheau for nine years before Tilikum killed and dismembered her."

Dawn is not the only human casualty.

10 John Hargrove resigned in 2012 over the conditions of the whales

Before he arrived at SeaWorld, Tilikum was involved in the death of another trainer.

The incident happened at Sealand of the Pacific, a marine park that has since closed down in British Columbia, Canada, in 1991, with the trainer accidentally falling into a tank with Tilikum and two other whales.

Then in 1999, trespasser Daniel Dukes was found dead after entering Tilikum’s tank at night.

10 Credit: Reuters

Dawn died while swimming with a killer whale at SeaWorld

'A whale grabbed me and held me under'

Jeffrey claims attacks on trainers were common because stress made the orcas hyper-aggressive - but many of the incidents weren't reported.

“I was involved myself and witnessed other trainers getting dunked, and shoved by the whales, and Taku rammed me underwater," he says.

"This was never reported. But 'stuff' like this was a common occurrence."

John adds: "I worked with 20 different orcas in my career and swam with 17 of them.

"The three I didn’t swim with were because they were classified as 'non-waterwork whales' and no trainer swam with them.

"I had 10 major 'waterwork aggression' incidents during my career where whales grabbed me in their mouth and held me under."

10 Recent reports suggested up to 100 large sea mammals were being kept in small 'whale jails' in Russia before being sold on Credit: Masha Netrebenko/The Siberian Times

Jeffrey claims trainers were forced to lie to the public about the whales, passing off injuries they sustained from captivity as normal.

One of those is dorsal fin collapse, where the dorsal fin leans to one side.

The reason this happens isn't totally known, but scientists have suggested it's due to stress and reduced activity.

Jeffrey explains: “We were also given scripts for educational shows that were filled with errors that were actually public relations talking points.

"For example, when we spoke to kids we were told to tell them that killer whales live 25 to 30 years on average. This is not true.

"We also told the public that dorsal fin collapse was genetic or a fairly regular occurrence in the wild, which is isn't.”

In the wild, killer whales live to between 50 and 80, where in captivity their life expectancy is around 17 years.

10 Dorsal fin collapse is common in captive whales but only one in five orcas have it at sea Credit: Magnolia Pictures

Still feel guilt

Jeffrey left the job in 1995 and John quit in 2012, with both realising the negative impact the industry was having on both trainers and whales.

John now campaigns for better conditions, saying: "By speaking out it helps with the guilt I still keep buried inside me for being able to walk away and go on with my life when those whales I loved more than anything, could not."

Jeffrey, a medical doctor and specialist in physical medicine and rehabilitation, now lives in Washington. He campaigns against keeping orcas in captivity, and in 2016 SeaWorld announced they were ending their breeding programme

The last bred killer whale, a female calf called Kyara, was born in April 2017. She died just three months later from suspected pneumonia.

10 SeaWorld's breeding programme proved controversial Credit: AP:Associated Press

Twenty-two orcas now remain at the park's Orlando, San Antonio, and San Diego attractions. The youngest Amaya was born in 2014.

Jeffrey says: “It's hard to significantly improve their lives in small pools as most of the issues of deconditioning, broken teeth, hyper-aggression, mortality and morbidity are a function of captivity.

“A step in the right direction is to a protected sea pen where they have an entire cove to play, interact with kelp and fish, be together and not performing shows, but also an area where they can get teeth flushings and medical care.”

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'Abusement' parks

PETA Director Elisa Allen says: "In the open ocean, orcas travel more than 100 miles each day, feeling the currents, seeing other marine life, accompanied by family, and raising and teaching their offspring – but in captivity, they can do little else but swim in endless circles.

"This life of frustration, stress, and loneliness takes an enormous toll, and orcas in captivity die far short of their natural life expectancy.

"Anyone with a heart can only be moved by their plight and stay far, far away from these 'abusement' parks."

Dr. Chris Dold, SeaWorld’s Chief Zoological Officer said: "We are disappointed by TripAdvisor’s new position that ignores the educational value and conservation mission of professionally accredited zoos and aquariums. "SeaWorld believes deeply in the mission of these organizations. As a member of World Association of Zoos and Aquariums (WAZA), certified by American Humane, and accredited by Association of Zoos & Aquariums (AZA) and Alliance of Marine Mammal Parks and Aquariums (AMMPA), as well as numerous other certifications and accreditations from leading accrediting bodies, SeaWorld maintains the highest standards of care for all animals, including cetaceans.

"And regardless of TripAdvisor’s position, SeaWorld will continue to advance education and animal conservation efforts along with our millions of supporters, professional scientists and other science based organizations around the world.”