Researchers begin necropsies on dead pilot whales on Kice Island
There’s one question on everyone’s minds after two sets of pilot whales beached themselves in Southwest Florida this week: Why?
The answer won’t come so easy. While officials say it could take weeks or months for samples of the whales’ bodies to be tested, experts say they are unable to find a cause for about half of all mass strandings worldwide.
“It’s very difficult to prove things in science, in general,” said Laura Dias, of the National Oceanic and Atmospheric Administration. “It’s not like math where we can say two plus two is four.”
Scientists still know relatively little about pilot whales. Joseph R. Geraci, a national expert in marine mammal strandings, told Newsday in a 2002 article that “pilot whales live such complex lives in such an inaccessible habitat that I don’t think even a hundred years from now we’ll know everything about their lives with absolute certainty.”
Dias said pilot whales have a huge home range and are not as easy to observe as land mammals.
“It’s more difficult to study an offshore species,” she said.
A team of researchers spent Friday performing necropsies, or animal autopsies, on 25 beached whales on Kice Island, a barrier island south of Marco. The team found 16 females and nine males. One of the females was pregnant, and two were lactating. All were dead by the time they were discovered Thursday morning.
Although military sonar is thought to be responsible for certain strandings of marine mammals, the NOAA has made contact with the Navy, which said it has not been doing any sonar training in the area, according to NOAA spokeswoman Kim Amendola.
Samples taken Friday from the whales will require a full lab analysis. As part of their investigation, biologists are looking at whether the whales might have been struck by the measle-like morbillivirus, an epidemic that’s blamed for killing more than 1,000 migratory bottlenose dolphins along the U.S. Eastern Seaboard last year.
The virus was ruled out as a cause for the whale stranding and deaths last month in the Everglades and the Florida Keys.
Officials have decided to leave the dead whales on Kice Island in their current location and let nature take its course. They stressed that it’s a felony to touch or interfere with the whales, saying wildlife officers and other agencies would be patrolling the area to keep violations at bay.
Thursday’s discovery of the 25 pilot whales brought the death toll to 33 in Southwest Florida in recent days. A separate stranding near Lovers Key State Park in south Lee County left eight whales dead.
Researchers performed necropsies on the Lee County whales but, like the Kice Island whales, why they beached themselves is a puzzle.
NOAA officials said the two groups of whales might be part of the same pod. Pilot whales often travel in groups of 30 to 50.
Mass strandings happen most frequently in south Florida, New Zealand, Scotland and Cape Cod, Mass., according to Regina Asmutis-Silvia, executive director of the Whale and Dolphin Conservation in Massachusetts.
It’s not necessarily unusual for there to be multiple strandings in a short time period, she said. “There tend to be stranding seasons. It could also be that there are additional pods of animals in the area that also strand, or that members of the same pod strand over a series of days.”
Viruses, noise, fishing entanglements, natural causes and boat strikes can all cause marine mammals to become stranded, Asmutis-Silvia said. Changes in the tide can also contribute.
One study published in 2009 in the Environmental Pollution journal suggested coastal pollution affects the brain development of marine mammals, leading to strandings. Hearing loss has also been shown to contribute to strandings, although researchers don’t believe it is a factor in the Kice Island incident.
Russ Rector, a longtime marine mammal activist from Fort Lauderdale, has closely watched the news unfold on the whales coming ashore and dying here. He said the story may not be over, especially with more cold fronts on the way, which he believes may be one of the causes.
“There is going to be more,” he said. “Just get ready for it, you can count on it. It looks like to me it’s going to be a bad year for pilot whales.”
Members of the necropsy team said they’re also concerned about upcoming strandings.
“Trust me,” said scientist Gretchen Lovewell, of the Mote Marine Laboratory in Sarasota, “we’ve talked about it.”
Officials with the Rookery Bay National Estuarine Research Reserve said they would give an update about the Kice Island whales after test results come back, but Dias warned the tests might be inconclusive.
“Sometimes, you know, a stranding happens and you can’t find an answer,” she said.