First dolphin conceived with frozen sperm in Japan...died in Tokyo!

Japan's first dolphin conceived from frozen sperm died at an aquarium outside of Tokyo, keepers said.

Will, a 2.3-metre, 170-kg bottle-nosed dolphin conceived by artificial insemination and born in September last year, died early Tuesday, Kamogawa Sea World said in a statement.

"We're all overcome by grief," said Kazutoshi Arai, a spokesman for the aquarium, in Chiba prefecture (state).

Keepers transferred Will to a special treatment pool last week with his mother, Norma, after the young dolphin suddenly stopped eating, according to the statement.

Preliminary autopsy results suggested Will suffered from volvulus, or an abnormal twisting of the intestines, the aquarium said.

Scientists have been trying to improve insemination methods in an attempt to reduce inbreeding in captivity and preserve endangered dolphin species. It is unclear whether Will's death had anything to do with the method of his conception.

The world's first artificially conceived dolphins were born in 2001 in Hong Kong.