 Aquariums have tried housing other species of whales in captivity . The success of belugas turned attention to maintaining their relative , the narwhal , in captivity . However , in repeated attempts in the 1960s and 1970s , all narwhals kept in captivity died within months . A pair of pygmy right whales were retained in an enclosed area ( with nets ) ; they were eventually released in South Africa . There was one attempt to keep a stranded Sowerby 's beaked whale calf in captivity ; the calf rammed into the tank wall , breaking its rostrum , which resulted in death . It was thought that Sowerby 's beaked whale evolved to swim fast in a straight line , and a 30 metres ( 98 ft ) was not big enough . There have been attempts to keep baleen whales in captivity . There were three attempts to keep gray whales in captivity . Gigi was a gray whale calf that died in transport . Gigi II was another gray whale calf that was captured in the Ojo de Liebre Lagoon , and was transported to SeaWorld . The 680 kilograms ( 1 @,@ 500 lb ) calf was a popular attraction , and behaved normally , despite being separated from his mother . A year later , the 8 @,@ 000 @-@ kilogram ( 18 @,@ 000 lb ) whale grew too big to keep in captivity and was released ; it was the first of two gray whales , the other being another gray whale calf named JJ , to successfully be kept in captivity . There were three attempts to keep minke whales in captivity in Japan . They were kept in a tidal pool with a sea @-@ gate at the Izu Mito Sea Paradise . Another , unsuccessful , attempt was made by the U.S. One stranded humpback whale calf was kept in captivity for rehabilitation , but died days later . 
