Around a dozen members of the group were outside the East Wintergarden building in London’s Canary Wharf ahead of the convention, including some dressed as orcas.
Some wielded picket signs with slogans including "animal abuse is bad business" and "life in a concrete box is no life".
The charity is urging Abta to add facilities and attractions that exploit dolphins, whales and orcas to its list of unacceptable practices.
"Abta’s animal welfare guidelines lists wild-animal performances among its unacceptable practices," a Peta spokesperson said. "But why is it OK with letting marine mammals endure a life of misery in watery prisons?"
