A female bottlenose dolphin has died at a Japanese aquarium only weeks after breaking a national record of more than four decades in captivity, an official said Thursday. Nana, thought to be around 47 years old, was discovered drowned on Tuesday at a natural cove of Shimoda Aquarium in Shizuoka, central Japan, said official Kiyoshi Sakamoto. The death came less than a month after Nana reached 42 years and 10 months under human care, beating the previous record held by another dolphin at Kamogawa Sea World, southeast of Tokyo. The aquarium will conduct an autopsy on the dolphin as the exact cause of its death could not immediately be established, said Sakamoto, adding that Nana had recently lost her appetite.