More than 30 dolphins mysteriously washed up dead in the Lowcountry this spring. The big spike in strandings alarms federal researchers enough that they are conducting extensive tests on the remains.
From late February through early May, 32 bottlenose dolphins stranded, mostly in Charleston and Beaufort counties. That's three times as many as normally would be expected during those months.
"Right now we don't know why they died," said Wayne McFee, National Ocean Service marine mammal stranding program scientist. "Most of the animals we've had have been really decomposed." The testing will take months, he said.
The National Oceanic and Atmospheric Administration has designated the strandings as a "unusual mortality event," because they were unexpected and involved a relatively large number of animals. The designation gives forensic researchers funding to do detailed testing of remains, because of potential environmental and human health threats.
A dolphin that dies because of contamination or a virus can be bad news for people who live along the coast. Because the sea mammals are so close to humans in some ways, they are a prime "canary in the coal mine" of trouble in the water.
Marine mammal strandings along the South Carolina coast tend to spike in the spring and fall each year, when migrating animals are on the move. But in the past few years, strandings have spiked in mid-winter. The most likely explanation is the same winter cold snaps that led to mass bait fish kills along the beaches.
The cold depletes the shallows of food -- fish schools for the dolphin.
Dolphins that already are sick can't catch enough to sustain themselves, so they weaken and gradually die, sometimes of pneumonia.
More than 10,000 bottlenose dolphin are thought to roam along the Southeast coast. Some 40 dolphins strand on South Carolina beaches each year.