Scientists Explore Cause of Dolphin Deaths Scientists at the National Oceanic and Atmospheric Administration are trying to figure out what's been causing deaths of bottlenose dolphins over the last two decades. Elizabeth Shogren joins the scientists on an expedition near Charleston, S.C.
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Scientists Explore Cause of Dolphin Deaths

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Scientists Explore Cause of Dolphin Deaths

Scientists Explore Cause of Dolphin Deaths

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This is MORNING EDITION from NPR News. I'm Steve Inskeep.

The federal government is concerned about the number of bottle-nosed dolphins dying over the past two decades. In the late 1980s, several hundred dolphin deaths were documented, and now scores of dolphins are dying off the coast of Florida. The National Oceanic and Atmospheric Administration has launched several studies to find out why, and NPR's Elizabeth Shogren went offshore with the researchers.


The day starts with a search. The researchers and their helpers are in four small boats scattered across Charleston Harbor. They're looking for dolphins and exchanging tips by radio.

(Soundbite of boats)

Unidentified Man #1: Well, which way is the animal going?

Unidentified Man #2: Right now he's going east. He's kind of been back and forth a little bit, and he is staying down.

Unidentified Man #1: You want the animal if we can catch it?

Unidentified Man #2: Yes.

SHOGREN: They encircle the dolphin with a large net. A dozen people jump into the water. Some of them wrap their arms around the thrashing animal. Veterinarian Greg Bossart is one of two lead researchers. He's chest-deep in water overseeing the capture.

Dr. GREG BOSSART (Veterinarian): It's a little girl, who's being very feisty and jaw-popping, which is unusual for a female.

SHOGREN: Researchers maneuver a stretcher underneath the dolphin and hoist her on to the deck of a small boat. The crew lifts a canvas awning over the dolphin to protect her. Kneeling just inches from the dolphin's snout, Bossart orchestrates the elaborate exam. Eight other veterinarians join in. Some are crowded around the dolphin on the deck, and others stand in the water close by. One vet uses a hand-held sonogram to measure the dolphin's blubber thickness and check the health of her organs. Another measures her. The doctors work quietly. The dolphin's breathing is one of the loudest sounds.

(Soundbite of birds; dolphin breathing)

Dr. BOSSART: Go ahead and take a look at her mouth real quick. Let's see this. OK.

(Soundbite of water splashing; dolphin breathing)

Dr. BOSSART: Look at the color of her tongue. You look for any tongue tumors. We're seeing a lot of cancer in the tongues of these animals.

SHOGREN: Bossart has examined more than a hundred and seventy wild dolphins over three years in Charleston Harbor and in Florida's Indian River Lagoon. He's alarmed by the frequency of tongue and genital tumors on the animals, some cancerous and some viral, especially in the Florida dolphins. He believes it's a sign of a new disease or diseases perhaps caused by pollution, but this dolphin looks good.

Dr. BOSSART: Her tongue right now looks absolutely normal.

SHOGREN: They douse her with water regularly because dolphins can't sweat to cool themselves.

(Soundbite of water splashing)

SHOGREN: This exam is way more thorough than anything most humans would put up with. For the good of her kind, this wild dolphin is subjected to all kinds of intrusive procedures. Bossart guides a tube down her throat to test her stomach fluids. Another vet takes samples of urine and feces. Then he injects a local anesthetic into her skin and slices off a small chunk of blubber.

Dr. BOSSART: The biopsy's very important because we're looking for contaminants and, in fact, a lot of these contaminants are human pollutants, like PCBs and chlorinated hydrocarbons, things that man has introduced in the environment that these animals can concentrate and give to their young as well as impact their own body's health.

SHOGREN: Throughout the exam, the dolphin is quiet but seems very interested in what's happening to her.

Dr. BOSSART: She's curious. She's looking at what everyone's doing.

SHOGREN: After less than a half-hour, the doctors put her back in the water, but they're not quite done. One of the vets holds her, another applies branding irons, chilled in liquid nitrogen, to each side of the dolphin's dorsal fin.

Unidentified Man #3: Six on...

SHOGREN: Freeze branding each number takes a good 10 seconds.

Unidentified Man #4: Five, four, three, two, one, off.

SHOGREN: This dolphin gets number 865. The markings show up as a darker shade of gray. They'll last forever so researchers can identify her.

(Soundbite of drill)

SHOGREN: One of the doctors drills a hole through the fin to attach a radio transmitter. It will help them track her. The samples of blubber, urine and blood go immediately to a lab set up on the deck of a research vessel that's anchored alongside the examination boat. There are a couple dozen scientists and technicians working frantically. Pat Fair is in charge of this floating laboratory.

Ms. PAT FAIR (Researcher): It's protocol that these samples are processed immediately here, especially the blubber samples and the blood samples and all the biological samples.

SHOGREN: Fair is concerned about high levels of perchlorinated compounds, chemicals used as flame retardants, that she's found in the dolphins caught in Charleston. She says it's one of many ways that human activities onshore are hurting dolphins. She hopes that in two years when the five-year project is completed, they'll have some clear answers about what humans can do for dolphins.

Ms. FAIR: Things aren't all well with them and, you know, maybe hopefully we can make some corrections to our environment to try to do what we can to improve their conditions.

SHOGREN: Fair pauses from her work just for a moment to watch the dolphin swim away back into the wild.

(Soundbite of water splashing)

SHOGREN: Elizabeth Shogren, NPR News.

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