Dolphin death leads to review of breeding program

National Aquarium plans artificial insemination, isolating nursing pairs

August 08, 2004|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

Stung by the death of a 4-month-old dolphin that was roughed up by two older males, the chief scientist at the National Aquarium in Baltimore has launched a review of the dolphin breeding program that he expects will lead to major changes.

"I am evaluating this entire colony in terms of what kind of breeding program we will have. It is going to be restructured. There's no doubt about that," said Dr. Joseph R. Geraci, the aquarium's senior director of biological programs and an international authority on marine mammals.

To start, he plans to segregate nursing pairs from male animals and use artificial insemination.

The death was the second in the aquarium's dolphin pool this year. On April 27, a 10-day-old male died of bacterial meningitis.

Geraci said his review was precipitated by the latest death July 25 of a female named Bridgit. In addition to the bullying the animal suffered, initial necropsy results showed signs of infection.

But it's still unclear what caused Bridgit's death. A final report from the Johns Hopkins University's comparative anatomy lab is expected this week.

The deaths have shocked and disappointed aquarium personnel, who had watched the dolphin colony successfully raise all three calves born in 2001.

"I think we have stated that the wind was in our sails then," Geraci said. "We were hopeful we could continue that."

In that hope, a large male named Bob was shipped to Baltimore in March last year from the Living Seas exhibit at Walt Disney World in Florida. Bob bred with two of the aquarium's three eligible females.

But both calves born this spring are dead. So far, the deaths have not provoked outside investigations.

Marine mammal displays are regulated by the Animal and Plant Health Inspection Service, a division of the U.S. Department of Agriculture.

After a Sun inquiry, Dr. Robert A. Willems, the agency's acting regional veterinarian, called aquarium officials.

He determined "there was no violation of the Animal Welfare Act, so we are not doing an investigation," said APHIS spokeswoman Susan Hall.

American Zoo and Aquarium Association spokeswoman Jane Ballentine said the group's accreditation commission is waiting for final necropsy reports on the latest fatality in Baltimore. The aquarium is regarded as a leader in the industry, she said, and is not scheduled for an inspection until March 2006.

Potential problems

The well-being of Baltimore's dolphin colony is no small matter.

The National Aquarium draws more tourists to Baltimore than any other attraction except the Orioles. Aquarium officials said their dolphin shows -- six daily in summer -- are one of the biggest draws.

Visitors rarely see evidence of it, but infection and aggression are common hazards for marine mammals in the wild and in captivity. The former is unavoidable, said Ken Ramirez, vice president of marine mammal programs at Shedd Aquarium in Chicago.

"You'll find the water quality [in aquariums] is very good," he said. But dolphins live in the same water they urinate and defecate in. They eat fish that are frozen, but they're not sterile. "A normal, healthy animal is not going to have a problem with it, but if they become immune-compromised, they become susceptible."

Detecting illness can also be difficult. Wild animals tend to mask their symptoms to avoid attracting predators.

Calves pose additional problems, in part because their human handlers aren't as attuned to their behavior as they are to adult dolphins.

The calf that died in April succumbed to meningitis, an infection of the lining of the brain caused, in this case, by a common streptococcus bacterium.

The inflammation affects the central nervous system, causing neurological and behavioral changes.

"In cattle, they refer to it as `stupid calf syndrome,' where the calf can't really find the place to nurse," said Brent Whitaker, the aquarium's director of animal health. "That's what we were seeing with this calf. It was trying to nurse, but it just wasn't getting it right. At the time, we didn't really know how to interpret it."

Social order

Geraci is investigating what led to Bridgit's death last month. In addition to infection, there appears to be a complex interplay of male aggression and poor mothering -- the stuff of soap operas, only in a glass-walled tank.

"This is an animal colony that is dynamic," said Geraci. "Changes are going on all the time. ... They're continually working toward establishing some kind of dominance or social order."

The National Aquarium has nine dolphins. They include three juveniles (Spirit, Maya and Raven, born in 2001); three breeding females (Nani, 32, Shiloh, 22 and Chesapeake, 12); and three males (Shadow, 13, Cobie, 13, and Bob, 23).

With the females ready again to be bred, and with Shadow and Cobie too young, the aquarium turned to outside help.

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