HOLLYWOOD - The director of Oscar-winning documentary "The Cove" said the recent death of a trainer at SeaWorld in Florida proved whales and dolphins should not be held in captivity.

Speaking after collecting his Oscar at the Kodak Theater, Louie Psihoyos said the death of trainer Dawn Brancheau last month supported claims made in his film that cetaceans should not be used in amusement parks.

"There's never been a wild dolphin or an in the history of man known to have killed a human being in the wild," Psihoyos said.

"And you have one killer whale here killing three human beings in one lifetime. This teaches us that these animals don't belong in captivity.

"Jacques Cousteau said the educational benefit of watching a dolphin in captivity would be like learning about humanity only by watching prisoners in solitary confinement.

"If you take a captive animal out of the wild and you force him to do stupid tricks for our amusement, it says more about our intelligence than it does theirs."

In late February Tillikum killed SeaWorld trainer Dawn Brancheau after grabbing her ponytail and pulling her into the pool. In 1991, he was one of three whales at Oak Bay’s Sealand of the Pacific involved in the drowning of 20-year-old trainer and marine biology student Keltie Byrne after she slipped into the pool.

Tillikum was also in the Orlando SeaWorld pool in 1999 when 27-year-old Daniel Duke apparently climbed into the water after staying inside the attraction after it closed for the night. His body was found the next morning draped across Tillikum's back.

Psihoyos's film centers around the bloody annual cull of dolphins in the Japanese coastal town of Taiji, where the animals are herded into a naturally fortified inlet before being sold to amusement parks or killed for meat.

The main protagonist in the film is activist Rick O'Barry, the man who trained dolphins for the hit 1960s television series "Flipper."

O'Barry attempted to unfurl a small banner on stage at the Oscars on Sunday before television producers abruptly cut away to show audience members.

Psihoyos said the banner urged people to send a texted phone message DOLPHIN to 44144 to register support for the campaign.

He later denied his movie was an example of "Japan-bashing" and was intended as a public health warning to Japanese who are sold dolphin meat contaminated by unsafe levels of mercury.

"This movie is a love letter to people in Japan," Psihoyos said. "I myself have had mercury poisoning from eating the wrong kind of fish.

"Our hope is the Japanese people will see this film and decide themselves whether animals should be used for meat and for entertainment.

O'Barry added: "We like the Japanese people and there's no Japan bashing from this film. The Japanese people have a right to know.

"This film will do what the Japanese media failed to do, and that is inform the people so they can make up their own mind about what they want to do. We're not telling the Japanese people what to do."