Okinawa Churaumi Aquarium has constructed a new large containment net as a research facility for our foundation, and to facilitate the growth and breeding of large species of elasmobranchs including whale sharks. This large offshore containment net is 46 m in length, 35 m in width, 20 m in depth. It contains 32,200 m³ of water, which is four times larger than Okinawa Churaumi Aquarium’s Kuroshio Sea Tank. This large containment net will allow us to continue to provide animal welfare while we undertake conservation research and study the breeding of whale sharks and mantas.

TManatees are very cautious, and we don’t want to disturb them with even the slightest light or sound during the night. So that we can observe their breeding behavior at night, we installed a special monitoring camera in the manatee pool that can record in the dark. This camera is linked with our aquarists’ phones so the manatees can be monitored in real time. Not only has it made it possible to monitor them both day and night, but it has also improved security, and the immediate assessment and appropriate rapid response to an emergency.  This initiative is part of the ongoing digital transformation (DX) to improve the quality of animal welfare.

The ecology of giant mantas is mostly unknown, as they had never been reared in Japan or overseas. During the world’s first successful exhibit at our facility in 2018, we were able to observe its behavior, and conduct blood tests and ultrasounds to better understand giant manta physiology and ecology. We noticed unusual behavior such as unstable swimming and feeding during the colder months. By adjusting the food given in colder months, and reducing interference from other animals, the problematic behavior stopped, creating a good environment all year.

In recent years, we have learned that wild whale sharks swim up and down between warm surface waters and cold deep-sea waters to adjust their body temperature. As global sea temperatures rise, Okinawa Churaumi Aquarium has installed a water temperature adjusting system, so whale sharks are better able to regulate body temperature, in this improved living environment.
Studies of thermoregulation of whale sharks can be viewed here.

Pygmy killer whales in the wild can be aggressive toward other dolphins. Aquarium staff had observed these aggressive behaviors toward other dolphins, while social behaviors such as swimming and playing together were limited. At Okinawa Churaumi Aquarium, efforts were made to control aggressive behavior using behavior modification methods (equivalent to psychotherapy in humans), to encourage social behavior with other dolphins. By repeatedly rewarding dolphins who didn’t show aggressive behaviors with toys, it reduced aggression, and increased socialization.

Aggressive behaviors occur when rearing several hawksbill turtles in the same tank. To reduce aggressive behaviors of hawksbill turtles and create a comfortable environment, Okinawa Churaumi Aquarium studied variations in rearing environments while monitoring blood corticosterone concentration, a stress indicator in sea turtles. The results showed that adding chunks of limestone or rocks in the tank reduces turtle stress and decreases aggressive behaviors. The sea turtle pool now includes chunks of limestone, and aggressive behaviors between hawksbill turtles is rarely seen.