The California Coastal Commission has granted SeaWorld planning permission to expand its Orca facility in San Diego on the basis that it cannot add any new whales from the wild to its tanks and that none of the park’s orcas will be allowed to breed.

SeaWorld has been under immense pressure from wildlife advocates, who want all of the park’s cetaceans released into sea pens to live out the rest of their lives. The company’s profit margin has dropped by more than three quarters as it struggles to regain its reputation, tarnished by the 2013 documentary Blackfish, which alleged a SeaWorld orca killed its trainer because it was traumatised by its living conditions. The expanded facility was a way to counter this, though the breeding and importation ban effectively means the San Diego park’s 11 orcas will be the last to ever inhabit the park.

In a statement, SeaWorld said it was disappointed with the ruling arguing that breeding is “a natural, fundamental and important part of an animal's life”, adding that depriving a social animal of the right to reproduce was “inhumane”.

In Canada, following a similar ruling by the Vancouver Park Board – which allowed whales and dolphins to be kept in captivity but prohibited breeding or otherwise promoting reproduction among captive mammals – Vancouver Aquarium took the body to court in July 2014, contesting that, short of sterilisation, the breeding ban was an “impossible task and would be psychologically damaging to the highly social animals”. The case collapsed as the outgoing board tried to push the ruling through at the last minute, meaning the breeding ban was abolished.

The park’s US$100m (€88m, £66m) developments will triple the size of its tanks in San Diego, with further plans for similar expansions at its other US parks. The ban only applies in the state of California, meaning SeaWorld’s other 13 whales at its attractions in San Antonio and Orlando are not included in the decision. SeaWorld officials have not said whether the company is planning litigation, stating only that “all options are being considered.”