visitors reaching 50 million in 2019. In 2020, the number of tourists in Okinawa Prefecture decreased significantly due to the COVID-19 pandemic. Aquarium The public aquarium is a part of the Ocean Expo Park located in Motobu, Okinawa. The aquarium is made up of four floors, with tanks containing deep sea creatures, sharks, coral, and tropical fish. The aquarium is set on 19,000 m2 of land, with a total of 77 tanks containing 10,000 m3 of water. Water for the saltwater exhibits is pumped into the aquarium from a source 350 m offshore, 24 hours a day. The Kuroshio Sea The main tank, called the Kuroshio Sea, is long, wide and deep. It holds of water and features an acrylic glass panel measuring with a thickness of , the largest such panel in the world when the aquarium was opened. Whale sharks and manta rays are kept alongside many other fish species in the main tank. Since 2015, the aquarium has also had a reef manta ray with a black body. Since 2018 they also keep giant oceanic manta ray. The world's first birth of a manta ray in captivity was at the aquarium in 2007. This species and the giant oceanic manta ray were only recognized as separate species in 2009; they were both classified as Manta birostris until then. By the time the mother died in 2013, seven puppies were born and four survived. There is a record that the male reef manta ray, which lived in captivity in 1992, lived for about 23 years. The first attempt of keeping whale sharks in an aquarium was in 1980, and it remains one of the few aquariums that maintains the species. Most were obtained from incidental catches in coastal nets set by fishers (none after 2009), but two were strandings. Several of these were already weak from capture or stranding and some were released, but initial survival rates were low. After the initial difficulties in maintaining the species had been resolved, some have survived long-term in captivity. The record for a whale shark in captivity is an individual that, as of 2021, has lived for more than 26 years in the Okinawa Churaumi Aquarium from Okinawa Ocean Expo Aquarium. Okinawa Churaumi is trying to breed whale sharks in captivity, which has never been achieved by an aquarium. Their oldest male reached sexual maturity around 2012 and began to show