A rare deep diving whale rescued from a Maui beach earlier this month has died after spending two weeks at a dolphin and whale hospital on Hawaii's Big Island, federal officials have said.
Tests showed that the male Blainville's beaked whale had moderate pneumonia, a severe gastrointestinal problem, and kidney disease, said David Schofield, a marine mammal response co-ordinator for the National Oceanic and Atmospheric Administration.
Each of these diseases could have killed the animal, he said.
It was not clear how the whale contracted the illnesses, although a viral infection was one possibility.
"We're sending tissues out for analysis to learn why it perished so quickly," Mr Schofield told reporters.
The Coast Guard flew the whale to Hilo from Maui so it could be cared for at the Hawaii Cetacean Rehabilitation Facility. The 11ft 6in (3.5m) long, 1,800lb (800kg) animal was found stranded at a Kihei beach on August 16.
Scientists rarely have chance to study beaked whales because they are frequently diving in deep waters, hunting for squid. Mr Schofield said the whales spend only about 3% of their time at the surface.
Few beaked whales have survived more than a few days after being rescued from a stranding. The longest one has lived after being rescued is four weeks, Mr Schofield said.
"If you have a deep diving animal that's coming in from far off shore, it's spending a lot of time deteriorating. By the time we get it, it's in really bad shape," he said.
Beaked whales have been known to be more vulnerable to the harmful effects of Navy active sonar than other whales. Scientists are not sure why, but one theory is that sonar may startle the deep diving whales, causing them to surface too rapidly and suffer ear damage.
But Mr Schofield said there was no sign that this animal was affected by sonar.
A test conducted in Hilo showed the whale was hearing normally. Officials also planned to conduct a CT scan on the whale's head to learn more.
The whale was the second animal taken to the marine mammal hospital at the University of Hawaii at Hilo since it opened in February.
Earlier this year, a striped dolphin died after just 18 hours at the facility. Veterinarians believe it was suffering from an acute viral infection.
The facility takes care of sick or injured whales and dolphins which might otherwise have to be destroyed.
According to NOAA, there are an estimated 1,200 to 2,200 Blainville's beaked whales in Hawaiian waters. The Northern Gulf of Mexico stock is about 100 animals. There is no current estimate for the Western North Atlantic Stock. The species is protected under the Marine Mammal Protection Act.