TOKYO - A giant manta ray baby that was believed to be the first born in captivity died Thursday after being abused by its father, Japanese keepers said.

A baby giant manta ray swims inside a huge fish tank at the Okinawa Churaumi Aquarium in Motobucho, Okinawa Prefecture (State), southwestern Japan, Saturday, June 16, 2007. [AP]

The female baby manta was born Saturday at the Okinawa Churaumi Aquarium, more than a year after its parents mated.

The baby manta, which was more than 6 feet wide, was pronounced dead Thursday morning after living only 4 1/2 days, the aquarium said in a statement.

"To our greatest regret, (the baby) didn't last very long, despite our meticulous care," it said.

Keepers believe the baby died of bruises and cuts, apparently caused by its abusive father that constantly chased after the baby, often slamming into it, the aquarium said.

The reason for the father's violence was not immediately known, and the baby's death was still under investigation, the aquarium said.

Okinawa is about 1,000 miles southwest of Tokyo.