Captive orcas
Dozens of orcas (killer whales) are held in captivity for breeding or performance purposes. The practice of capturing and displaying orcas in exhibitions began in the 1960s, and they soon became popular attractions at public aquariums and aquatic theme parks due to their intelligence, trainability, striking appearance, playfulness, and sheer size. As of 24 March 2024, around 55 orcas are in captivity worldwide, 33 of which were captive-born.[1][2] At that time, there were 18 orcas in the SeaWorld parks.[3]
The practice of keeping orcas in captivity is controversial, due to the separation from their familial pod during capture, and their living conditions and health in captivity.[4] Additionally, concerns have been raised regarding the safety of animal trainers entering the water to work with captive orcas, which have been responsible for numerous attacks on humans—some fatal. Attacks on humans by wild orcas are rare, and no fatal ones have been reported.
Captivity conditions[edit]
Tank size and water conditions[edit]
Legal requirements for tank size vary greatly from country to country. In the US, the minimum enclosure size is set by the Code of Federal Regulations, 9 CFR 3.104, under the Specifications for the Humane Handling, Care, Treatment, and Transportation of Marine Mammals.[77] In 9 CFR 3.104, Table III classifies killer whales as Group I cetaceans with an average length of 24 feet (7.3 m). Based on length, Table I states up to two killer whales may be held in a pool with a minimum horizontal dimension (the diameter of a circular pool of water) of twice that length or 48 feet (15 m) and a minimum depth of 12 feet (3.7 m), giving a minimum volume of 21,700 cubic feet (615 m3) for two killer whales. Each additional killer whale requires a pool with an additional 10,900 cubic feet (308 m3) of volume. 9 CFR 3.104 also requires a minimum of 680 square feet (63 m2) surface area per killer whale in Table IV (the example with a cylindrical tank 48 feet (15 m) in diameter for two whales provides 905 square feet (84.1 m2) of surface area per killer whale). Swiss regulations require a larger minimum volume: 400 square metres (4,300 sq ft) × 4 metres (13 ft) deep for two killer whales, or 1,600 cubic metres (57,000 cu ft). The Alliance of Marine Mammal Parks and Aquariums (AMMPA) goes further, and recommends 1,918 cubic metres (67,700 cu ft) for two killer whales.[78] The US exhibitors of captive killer whales belong to the AMMPA, but exhibitors in other countries do not.[79]
The Miami Seaquarium has been criticized for the small size of the tank holding their sole killer whale, Lolita, which is less than two of her body lengths wide at any point.[80] The tank used by Marineland of Canada for Kiska was an estimated 40 metres (130 ft) x 20 metres (66 ft) wide. Kiska would complete 879 laps around her tank every day which was a total distance of about 100 km, the minimum distance most wild orca pods travel daily. Kiska developed ritualistic, repetitive behaviours (such as repeatedly rubbing her skin against the tank until injured, thrashing, and floating motionless in one spot) that indicate stress and are abnormal for wild orcas.[81]
Nutrition and medical care[edit]
On average, an adult killer whale in the wild may eat about three to four percent of their body weight daily,[82] or as much as 227 kg (500 lb) of food for a six-ton male. Their diet in the wild depends on what is available, and may include fish, walruses, seals, sea lions, penguins, squid, sea turtles, sharks and whales.[83] According to SeaWorld, each of their adult orcas receives 140 to 240 pounds of food per day, primarily herring, capelin, salmon and mackerel. To maintain their alertness, the killer whales are fed at sporadic intervals throughout the day (as would happen in the wild) and feeding is often combined with training and shows. Each batch of fish is carefully tested to determine its nutritive composition, and each killer whale's weight, activity and health is carefully monitored to determine any special dietary requirements.[84]
Killer whales have been the subject of extensive medical research since their first capture, and much is known about prevention and treatment of the common viral and bacterial infections, including vaccination and use of antibiotics and other medicines.[85] Allometric principles and therapeutic drug monitoring are used to accurately determine the doses and avoid toxicity.[86]
Training[edit]
Whales are trained using positive reinforcement; usually by giving the killer whale food when they perform the desired tasks. If the animal is unsuccessful, it is asked again. Food withdrawal is only used in facilities considered to be improper. Food rewards are often called "least rewarding scenarios" as many whales find fish boring or are simply not hungry.[87] Secondary reinforcement—things not essential to life, such as play time, tactile rewards and fun games—can also be used as rewards.[88]