dolphin

Male dolphin Number 864 still swims around Fort Sumter, a decade and a half after he was trapped in a crab pot line, rescued, then took part in a federal dolphin health survey. Provided by Patrick Harwood

Some of the worst concentrations of man-made carcinogens ever found in dolphins were in the blubber of animals pulled from Charleston Harbor a decade and a half ago.

One of those dolphins tested was called "Number 864" by scientists. 

So it delighted Eric Zolman, a National Ocean Service biologist, to learn Number 864 had been spotted and photographed recently missing a few nips out of his dorsal fin, but really not much worse for wear at 36 years old — elderly for a male dolphin. 

"The animals around here certainly do carry a not-so-insignificant amount of contaminants. Thirty six, that's impressive," Zolman said. "I wish I could have seen him go by. Just being out there and swimming around, that's something."

This is a dolphin Zolman knows well. It was spotted in Charleston Harbor, just off Fort Johnson on James Island, where Zolman works, and where he freed it from a tangle of wire dragging along a crab trap in 2003. It's also where 864 was captured for the contaminant testing a few months later.

"It definitely looked healthy and big, too," said Patrick Harwood, a South Carolina State University communications instructor, who saw the animal break nearby and shot a photo.

Harwood became curious about the distinct 864 numbering that had been branded on the dorsal for the study. He was put in touch with Zolman.

Dolphin 864 is big. At nearly 9 feet long, it's one of the biggest dolphins to be recorded in the Charleston Harbor area.

Zolman thought he might have his hands full in 2003 when he waded into the waist deep water with another staffer to try to free the animal from the crab trap line. It was so exhausted it didn't struggle.

When they freed 864 they grabbed hold of the flippers and eased it to deeper water. The dolphin began to pick up his strokes as they went and swam tiredly away.

Fifteen years later, "it's great to see he's still out there alive and kicking," Zolman said.

Number 864 is one remarkable marine mammal. The average yearly life span of a bottlenose dolphin in the wild has been studied to range from the 20s to the early 40s, according to sources including SeaWorld and the National Oceanic and Atmospheric Administration.

Males don't tend to live as long as females.

"Around here, 36 is pretty old for a dolphin, so he's doing pretty well," Zolman said

With development and pollution problems escalating in the Lowcountry, Zolman considers it a heartening sign that a long-lived mammal like this one can make it in the mess of contamination researchers have detected.

The study, done at the Center for Coastal Environmental Health and Biomolecular Research at Fort Johnson, is one of a number of ongoing research projects into estuary and ocean health and the impact on humans.

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 considered a prime "canary in the coal mine" warning of trouble in the water.

They eat fish; humans eat fish. They live in the sea; humans swim in it.

For 864 to turn up when he did (during spring) is notable, too. Dolphins tend to calve in early spring, Zolman said, adding as a joke he might well have dropped by for his birthday.

Reach Bo Petersen Reporter at Facebook, @bopete on Twitter or 1-843-937-5744.

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