The aquarium released results of a necropsy from the University of Georgia College of Veterinary Medicine on Ralph, who died Jan. 11.
In a statement, aquarium executive director Jeff Swanagan said the whale shark's stomach "appeared abnormal, because it was thin-walled and perforated. This likely caused peritonitis, which led to Ralph's death." He said physical examinations of the aquarium's other male whale shark, Norton, have not revealed the same condition. Peritonitis is an inflammation of an important membrane in the abdomen.
Mr. Swanagan said Ralph began losing his appetite last year after a series of treatments was prescribed to the Ocean Voyager exhibit to suppress a parasitic leech commonly found on aquatic animals.
After several treatments, he said, the appetites of Ralph and Norton declined, and they eventually stopped eating.
Alice and Trixie, the two female whale sharks, were not exposed to the same number of treatments and have not shown the same behavior.
Mr. Swanagan said the whale sharks were given therapeutic food, fluids and medicine, their water was monitored and the method of treating the leeches was changed.
"There is no evidence that anything in the Ocean Voyager's environment led to Ralph's death," he said in the statement.