That leaping dolphin, one of the most beloved animals of the South Carolina coast, might be dying off in front of our eyes.

Nobody knows how many are really out there. More dolphins are dying tangled up in yards of crab pot lines and other marine gear. They are backing away from their usual behaviors as beachgoers and boaters crowd them.

The local population of the sea mammals is smaller than many people realize. Some people think the waters around Charleston are home to thousands of dolphins, said Lauren Rust of the Lowcountry Marine Mammal Network.

But the last survey by a federal team was done more than a decade ago, in 2008. It found only 350 living in Charleston area waters.

That survey team has been working in the Gulf of Mexico ever since, in the oily wake of the 2010 Deepwater Horizon spill.

Meanwhile, there are more people than ever haunting Charleston waters.

Dolphin deaths from crab pot entanglements alone have increased year to year — from one in 2013 to eight in 2018, said Wayne McFee, a National Ocean Service marine mammal stranding program scientist based in Charleston.

Dolphins wash up dead by the dozens each year, most of them malnourished, emaciated and sick. Researchers have found toxins in the blubber of dolphins in Charleston Harbor including some of the worst concentrations of man-made carcinogens ever found in the animals.

A virus that broke out from 2013 to 2015 along the East Coast killed more than 1,600 dolphins, including most of the 178 found washed up dead in South Carolina, according to NOAA.

"If you have animals already stressed or sick, one more factor could put them over the edge," Rust said. "It would not take a lot for 350 animals to disappear in a hurry."

'Devastating'

While most bottlenose dolphins seen in Charleston waters tend to live here, it's not widely realized that many more dolphins are migratory, swimming up and down the East Coast. 

NOAA researchers have identified at least 50 "stocks." The total population of the western Atlantic bottlenose isn't known, but it has been estimated in the range of 100,000 animals. Of those, more than 1,600 died during the recent virus outbreak.

Few, if any, deaths involved local Charleston dolphin. But migrating dolphins come inshore in the fall to mate with local dolphins in Charleston waters and elsewhere. A more serious die-off could have been devastating to both, biologists have said.

Chad Hayes can tell when the migrating mammals show up: They are generally larger than the pod of dolphin in the Kiawah River that he knows individually after 16 years of studying them.

Hayes, a trained wildlife biologist and a former S.C. Department of Natural Resources fisheries biologist, has tracked the Kiawah dolphin pod — which he can tell apart by quirks in their individual dorsal fins. He is compiling a data set on their reproduction and striking behaviors that include strand feeding.

To strand feed, the mammals work in a group to corral fish, drive them ashore and then leap after them to eat. The spectacle is "Planet Earth" stuff. It's what a lot of people want to see who boat, take dolphin tours or group up on the inlet beaches to wait.

Hayes, who also runs Kiawah Charter Company, has thrilled customers by showing them these feedings for years — careful to keep a safe distance away. Not everybody else does, Hayes and others say.

More people than ever are reaching to feed or pet them from boats or docks, crowding feeding spots so close that at times they go virtually toe-to-nose with the chomping dolphin. The Marine Mammal network currently helps sponsor volunteers to back away people at Kiawah and other beaches.

Rust said her group has had to fend off more than 100 people per day.

"They could stop feeding at Capt. Sam's Spit (on the Kiawah River) if people don't quit the constant harassment," she said.

The dolphins are strand feeding at their old spots less often, Hayes said.

"Ten years ago, we saw strand feeding a lot more than we're seeing now. It's a huge difference. The past few years, the dolphins seem extremely stressed," he said. 

Washed up dead

It's a crucial time for Charleston dolphin, local researchers say.

"We could see a lot of these animals begin to suffer or disappear," Hayes said.

But not a lot is known about how to manage wild dolphin. Most studies have been with captive animals.

Research is suffering, too.

McFee is the last full-time staffer in the federal stranding program in Charleston that once had 15 employees. His job, forensics on animals that wash up, can be the first indicator of health problems with marine mammals, such as the virus.

Already, 16 marine mammals have washed up dead this year, including 14 dolphins. Most were emaciated, malnourished and sick. A dolphin that dies because of contamination or a virus can be bad news for people who live along the coast. They eat fish, and humans eat fish. They live in the sea, and humans regularly visit it.

Meanwhile, cuts are being made to NOAA across the board and the current proposed Trump Administration budget does away with most of the research at the National Centers for Coastal Ocean Science at Fort Johnson — cutting edge work such as ecosystem toxicology and shallow coral reef destruction. That includes McFee's job.

The work will be more in the hands of people like Rust and Hayes. 

To try to fill gaps in what's known about the local pods, Rust has launched Dolphin Count, a cellphone app for people to file sightings and behavior of the animals they encounter.

"I think, so far, the local dolphins are holding their own," she said, but nobody knows for sure. She cited viruses, rope entanglements and crowding, adding, "I think all these things are going to work against the species."

Dolphins "are resilient animals. They're extremely intelligent animals," Hayes said. "They're going to adapt to survive because they're going to have to."

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Reach Bo Petersen at @bopete on Twitter or 843-937-5744.

Science and environment reporter. Author of Washing Our Hands in the Clouds.