“I would not be on a set that had any kind of abuse toward animals,” he said, adding that he was not present when the scene was shot in Winnipeg, Manitoba, in October 2015.
The German shepherd, a 2-year-old named Hercules, is now “happy and healthy,” Amblin Entertainment, the film’s producer, and Universal Pictures, its distributor, said in a joint statement last week. Hercules was supplied and trained by Birds and Animals Unlimited, a company that frequently works with the film industry.
The American Humane Association, which monitors animals on movie sets and had a representative present during filming, said on Tuesday that the video was “misleading and edited.” Production was stopped after Hercules showed signs of stress, and he was not forced to swim, it said.
Several of the association’s findings were echoed by Gavin Polone, the film’s producer, in a column in The Hollywood Reporter, and by Birds and Animals Unlimited on its website. Mr. Polone said he was not present for the scene but had watched unedited footage of the day’s filming.
Mr. Polone, a vegan who said his will was set up to donate all of his money to animal charities when he dies, said Hercules was eager to swim during rehearsal, at one point “desperate to jump in.” The dog had to be held back by a trainer so he wouldn’t go in too soon, he said.
The footage seen in the TMZ video was taken after someone requested that Hercules jump in from the other side of the pool, according to both Mr. Polone and Birds and Animals Unlimited. At that point, the dog squirmed in the trainer’s arms and was visibly uncomfortable.
Birds and Animals Unlimited said that after “less than one minute,” Hercules was brought to the other end of the pool “from which he’d been conditioned to enter, and he did so happily.” Hercules had trained for months for the swimming scenes, the company said.
“He was chosen for the film based on his love of the water,” the company said.
In the second scene in the leaked video, the dog is seen submerging underwater. Birds and Animals Unlimited said “the current carried him closer to the wall at end of the pool than it had in previous takes.”
Mr. Polone said the dog was underwater for four seconds before a diver and handlers lifted him out of the pool. That scene was filmed after Hercules had willingly jumped in, though the footage might give the impression that he had been forced in earlier, Mr. Polone said.
Both of the episodes seen in the video remained “inexcusable,” Mr. Polone said. The trainer should have stopped trying to get Hercules to go in once the dog looked uncomfortable, and Hercules should never have gone underwater, the producer said.
“Seeing that distraught dog in the video did not comport with what I had observed in the prior weeks of production,” he said.
After Hercules went underwater, handlers put him in a warming tent and he did not show signs of stress, the American Humane Association said. The association requested a full veterinary checkup to ensure that the dog remained healthy, it said.
It remains to be seen what effect the defense will have on the box office numbers. People for the Ethical Treatment of Animals has maintained its call for a boycott of the film.
In emails to Mr. Polone, Lisa Lange, a senior vice president of PETA, suggested that he “pledge to never use live animals in films again.” A PETA spokeswoman said the organization believed that live animals should be removed entirely from movies and television.
Mr. Polone rejected the suggestion. He said Hollywood should focus on improving its protection of animals on set, and he criticized the American Humane Association’s ability to monitor animals on set.
“I say that we build a better method of protecting animals on sets through a better animal-protective service,” he wrote.
The A.H.A. said last week that it put its employee who was present during filming on administrative leave. A full investigation by an independent animal cruelty expert will be done by the end of the week, it said.
“We take extraordinary steps to ensure the safety of animals, starting long before a film starts shooting with a rigorous script review, detailed inspection of the sets and environment where animals will be, and on-set monitoring by trained certified animal safety representatives,” Mark Stubis, a spokesman, said in a statement.