The orca whale was portrayed by an animatronic whale, filmed off the coasts of Malta and Newfoundland, and stock footage taken at Marine World in Redwood City, California. The stock footage orca whales were named Yaka (a female) and Nepo (a male). They had both been captured in 1969. Nepo died in 1980 whilst Yaka died in 1997.
In the mid-1970s, executive producer Dino De Laurentiis considered a sequel to King Kong (1976) that may have had him go head-to-head with his own other animal monster movie of Orca (1977). The sequel, King Kong Lives (1986), did not eventuate until the mid-1980s though.
Many movie posters for the film featured a long text preamble that read: "THE KILLER WHALE! The killer whale, is one of the most intelligent creatures in the universe. Incredibly, he is the only animal other than man who kills for revenge. He has one mate, and if she is harmed by man, he will hunt down that person with a relentless, terrible vengeance - across seas, across time, across all obstacles".
The word "Orca" is derived from the classic Latin language, a zoological term, "Orca orcinus" [as stated in the film], or more accurately, it is referred to as "Orcinus orca". The phrase, "Orca orcinus", according to the film, translates into the English language, as "bringer of death".
"Orca" was also the name of Quint (Robert Shaw)'s fishing boat from Jaws (1975). The "Orca" vessel in that movie was named after the only natural enemy of the deadly white pointer shark species. The Orca (1977) major motion picture was made and released about two years after Jaws (1975).
According to website Wikipedia, "Producer Luciano Vincenzoni was first assigned to give the film a head start after being called by [executive producer] Dino De Laurentiis in the middle of the night in 1975. Upon admitting that he had watched Jaws (1975), Vincenzoni was instructed by de Laurentiis to 'find a fish tougher and more terrible than the great white' [shark, as in Jaws (1975)]. Having had little interest in sea life beforehand, Vincenzoni was directed to killer whales by his brother Adriano, who had a personal interest in zoology. Filming took place largely in Newfoundland during the fishing season. Most filming took place in the town of Petty Harbour, about 15 kilometres south of the capital city, St. John's".
Many film posters for the movie featured a long text preamble that read: "AN ANGRY THUNDERBOLT OF TERROR EXPLODES OUT OF THE OCEAN'S DEPTHS! Orca, the killer whale, destroys sharks, ships and men! He rules the ocean. He terrifies the earth. He is without mercy and without equal! Orca - the most powerful, the most fantastic animal in all the world.!"