Orca can be found in Hawaii's waters during all seasons, but sightings re extremely rare with an estimate of only 400 individuals in the entire Hawaiian archipelago (Baird et al). Orca are known to feed on both fish and marine mammals here in Hawaii, with Holo Holo Charters being the first to observe a family of five Orca attack, kill, and eat a juvenile Humpback Whale in Hawaiian waters.
The Orca or Killer Whale (Orcinus orca) is not a whale, but the largest species of the oceanic dolphin family (Delphinidae). They are sometimes referred to as blackfish, a group including pilot whales, pygmy and false killer whales, and melon-headed whales. It is the second-most widely distributed mammal on Earth (after humans) and is found in all the world's oceans, from the frigid Arctic regions to warm, tropical seas. It is also a versatile predator, eating fish, sea turtles, sea birds, pinnipeds, elasmobranchs, sirenians and even other cetaceans. This puts the Orca at the pinnacle of the marine food chain. Orcas have been known to attack baleen whales, in particular Gray and Blue Whales.
Orcas are distinctively marked, with a black back, white chest and sides, and a white patch above and behind the eye. They have a heavy and stocky body and a large dorsal fin with a dark gray "saddle patch" at the fin's rear. Males can be up to 9.5 m long (31 ft) and weigh in excess of 6 tons; it has been reported that especially large males have reached nearer 8 tons. Females are smaller, reaching up to 8.5 m (28 ft) and a weight of about 5 tons.
Large male orcas are very distinctive and are unlikely to be confused with any other sea creature. When seen from a distance in temperate waters, females and juveniles can be confused with various other species, such as the False Killer Whale or Risso's dolphin.