Zoo officials in Des Moines say the facility's 27-year-old harbor seal has died.
Television station KCCI reports Blank Park Zoo announced the seal named Red died during a procedure Friday.
Officials say the seal stopped breathing while under anesthesia and could not be resuscitated. He was undergoing a procedure following signs of weight-loss and abdominal pain.
The station reports Red came to the zoo in May 1986 from Sea World in California.