The second marine mammal park, then called an oceanarium, was established in St. Augustine, Florida in 1938. It was initially a large water tank used to exhibit marine mammals for filming underwater movies, and only became later a public attraction. Today Marineland of Florida claims to be "the world’s first oceanarium".
In November 1961, Marineland of the Pacific on the Palos Verdes Peninsula, near Los Angeles in California was the first park to display an orca in captivity, although the orca died after two days. The Vancouver Aquarium was responsible for the first orca ever held alive in captivity, Moby Doll, for 3 months in 1964.
Between the 1970s and the 1990s, technical advances and the public's increasing interest in aquatic environments prompted a shift to large marine mammal parks with cetaceans (mostly orcas and other species of dolphin) as attractions. Within this time SeaWorld USA evolved as the most prominent chain of marine mammal parks, with operations in Orlando, Florida, San Diego, California, San Antonio, Texas, and Aurora, Ohio (which has since closed down).
Many animal welfare groups, such as the WSPA, consider keeping whales and dolphins in captivity a form of abuse. The main argument is that whales and dolphins do not have enough freedom of movement within their artificial environments. The existence of marine mammal parks is thus very controversially discussed.