A baby beluga whale rescued in Alaska's Bristol Bay last month had multiple infections, according to necropsy results announced Wednesday.
"On postmortem exam we found that the beluga whale had infections in multiple sites, including his heart and lungs," Alaska SeaLife Center veterinarian Dr. Carrie Goertz said in a statement emailed to The Associated Press.
"Early tests had confirmed our initial suspicions that his immune system was not fully developed and that he was at risk of acquiring a life threatening infection. Despite our efforts to support his immune system, this was the unfortunate outcome," Goertz wrote.
The Alaska SeaLife Center was notified June 18 of the calf which had been separated from its mother, likely in a storm.
The center's stranding coordinator, Tim Lebling, flew to South Naknek from Seward, and brought the 5-foot-long beluga back in a small airplane in dry transport -- basically on an air mattress, covered constantly with wet towels.
It was believed to be the first beluga calf rescue in the United States, at least since federal record keeping began in 1972, SeaLife Center President Tara Riemer Jones said last week before the whale died. Other attempts at rescue resulted in calf deaths or, in one case, the calf being returned to its pod.
When the male calf arrived in Seward, it had its own pool at the center and around-the-clock care.
Since the event was so rare, beluga specialists from around the country came to Alaska to help care for the whale, including from the Georgia Aquarium in Atlanta, Shedd Aquarium in Chicago and SeaWorld in San Diego.
The calf had some gastrointestinal problems, and caregivers said the whale's immune system wasn't developed because it hadn't received any of its mother's milk.
Last week, the Alaska staff worked with other aquariums to provide supplements to help develop the whale's immune system.
Brett Long, the husbandry director at the center, said at the time: "It's a waiting game."
The calf was able to put on weight, gaining 5 pounds during his stay to weigh in at 115 pounds. He never officially was named, but most caregivers called him "Naknek."
But the whale's condition deteriorated over the weekend, and he died early Monday.
"Stranded cetaceans have a very low rate of survival, so his passing wasn't unexpected," Jones said. "We consider every day he survived a 'win.' "
Jones added, "But also, we do hope that the insights and learning we developed through his care will help future stranded animals like him."