​The last orca to be born at a SeaWorld park, which popularised killer whale shows in the 1960s but faced growing opposition in recent years, has been born at SeaWorld San Antonio in Texas.

Veterinarians at the park have not yet determined the gender of the calf, but said the baby and its mother Takara were in good shape and being monitored closely.

Attendance at SeaWorld's theme parks has been falling amid negative publicity and criticism from animal rights activists upset by the treatment of captive marine mammals.

Takara was already pregnant when the company said last year that it was suspending its captive breeding program and phasing out killer whale shows at its three parks in Orlando, San Diego and San Antonio.