A female bottlenose dolphin under human care for around 43 years, the longest in Japan, has died at an aquarium in central Japan, according to the facility operator.

(Shimoda Aquarium)

Nana, whose age was estimated at somewhere between 45 and 47, had lost her appetite since Oct. 4 and was found drowned in the facility's natural cove on Tuesday, according to Shimoda Aquarium in Shizuoka Prefecture.

After being hunted off the coast of Ito city in November 1974, Nana lived in the aquarium in the city of Shimoda. By 1994, she had given birth to eight calves.

On Oct. 4, her days in captivity reached 15,666, surpassing the previous longest record held by Kamogawa Sea World in Chiba Prefecture, east of Tokyo.

"We feel sorry as we were hoping she would live longer. We will use the experience gained by rearing her for this long period to take care of other dolphins," said an aquarium official.

At Shimoda Aquarium, the life-span of the majority of the bottlenose dolphins is between 10 and 15 years, according to the operator.