Two pygmy killer whales that were euthanized after stranding at a Maui beach last week were likely battling some kind of infection, federal wildlife officials said.
Both were adult males, according to Kristi West, associate researcher at the University of Hawaii, and both had abnormal, inflamed lymph nodes, indicating they were likely fighting some kind of infection at the time of the stranding,
In addition, they were both in poor body condition and had some unusual food items in their stomachs, including a Moorish idol in the esophagus of one. Usually, the whales, which are deep sea animals, feed on squid beaks and deep water fish.
Early on the morning of Sept. 24, National Oceanic and Atmospheric Administration officials responded to two whales that had stranded themselves on shore near Sugar Beach in Kihei, Maui.
NOAA officials believed the two were part of a group of six that they had been monitoring two weeks prior because they were milling and exhibiting unusual behavior at Maalaea Bay.
Based on drone footage from the Pacific Whale Foundation, David Schofield, NOAA’s regional marine mammal response coordinator said it appeared to be four healthy animals accompanying two debilitated individuals.
This, he said, was possibly caregiving behavior by the four whales for the two that were sick.
For another week after the two whales were euthanized, Schofield said the remaining four hung out at Maalaea Bay, but appeared to gradually range for longer distances. At the end of last week, Schofield said only three whales remained.
Today, there were no sightings of those remaining three whales, he said.
“We’re cautiously optimistic that they went out to sea and are out where they should be,” he said.
The Sept. 24 stranding of two whales occurred within a month of an earlier mass stranding at the same beach on Aug. 29.
In that incident, a group of 10 pygmy killer whales had stranded themselves on shore that morning, while a whale calf died nearby later that afternoon. NOAA officials euthanized four, and after numerous attempts, refloated six back out to sea.
Necropsy results for the four that were euthanized found that they had lung abnormalities and enlarged lymph nodes, as well, indicating they were fighting off some kind of infection. The calf was confirmed to have pneumonia.
West said she did not have lung results yet for the two most recently euthanized whales. What the seven whales examined, including the calf, have in common, so far, are inflamed lymph nodes.
She is also awaiting histopathology results, and will focus on screening for diseases such as morbillivirus and toxoplasmosis. She has also conducted a specialized, inner ear test that will help determine whether the animals were exposed to acoustic trauma prior to stranding.
Results take anywhere between several weeks to six months or more to get back.
Researchers do not know much about pygmy killer whales, which are typically found in deep waters. They are known to form social bonds from birth, and travel in groups of up to 50 individuals.
NOAA asks the public to keep a safe distance from marine mammals, and to report injured or stranded animals to its emergency hotline at 888-256-9840.