Baltimore (August 19, 2004) – National Aquarium in Baltimore officials have concluded their review of the circumstances of the death last month of 4-month-old dolphin calf Bridgit, and initiated changes to strengthen the marine mammal program.
Led by Dr. Joseph Geraci, veterinarian and senior director of biological programs, Aquarium veterinary staff and Johns Hopkins University veterinary pathologists conducted a necropsy – an animal autopsy. As suspected, preliminary pathology results indicate that she was septic with bacteria circulating in her blood and that the primary cause of death was pneumonia. Aquarium veterinary staff indicate that the pneumonia and subsequent sepsis may have been caused or worsened by the aspiration of water during roughhousing from the other dolphins days or weeks prior to the animal’s death. The necropsy showed no signs of internal trauma, such as bruising or broken bones.
“Essentially, this dolphin calf suffered from a serious infection that weakened her,” explains Dr. Geraci. “There’s no test we can do to determine which was the primary cause, but we can conclude that both the infection and the roughhousing contributed to her death.”
The morning she died, Bridgit was in the main pool with the dolphins slated to join the 11 a.m. show, including her mother Chesapeake, and Raven, Shiloh and Maya. The other five dolphins – Bob, Cobie, Shadow, Nani and Spirit – were separated in a back pool. When it was apparent that there was a problem with Bridgit, mother and calf were separated from the first group into another pool, and the decision was made to intervene with medical attention. The calf was removed from the pool and veterinary staff performed CPR and other life saving measures.
Two elements of dolphin behavior complicated Bridgit’s situation and an early diagnosis of infection. Dolphins create their own social hierarchies and use assertive behaviors to continually reinforce or change their position in the group, and the Aquarium respects the dolphins’ social order. As well, animals typically mask illness to protect themselves from predators, which complicates diagnoses. Intervening with a dolphin calf in terms of social hierarchy or to complete medical tasks has long-term impact.
As part of the Aquarium’s continual efforts to provide the best possible situations for the animals in its care and to stabilize the dolphin colony, Dr. Geraci has initiated changes to the dolphin breeding plans and to program management:
- Aquarium officials are looking closely at alternate breeding methods, including artificial insemination; the breeding program is under close review and may be reestablished in another form.
- Depending on the form the breeding program takes, the role of the breeding male may change. As well, since males typically break away from colonies as they mature, experts are weighing appropriate options for the young male dolphins – soon to reach maturity – for long-term relocation.
- With this evolving emphasis on breeding, the marine mammal department has been reconfigured and placed under the leadership of the director of animal training and marine mammals.
“Dolphin breeding has uncertain outcomes, and we’ve enjoyed tremendous results with five successful calves since 1992,” adds Dr. Geraci. “However, there are always risks, and we’re taking this time to assess those risks and reevaluate what’s best for our dolphins.”
The Aquarium’s dolphin breeding program has yielded five healthy dolphin calves: Cobie and Chesapeake (Bridgit’s mother) were born in 1992; Spirit, Maya, and Raven were born in 2001. All five are thriving at the Aquarium. Bridgit was the second dolphin calf lost at the Aquarium this year. The first, an unnamed male, died a few days after birth of bacterial meningitis.
The National Aquarium in Baltimore, a non-profit organization, is Baltimore’s leading attraction, hosting more than 1.6 million visitors per year. The Aquarium’s mission is to connect people with aquatic life in order to create a better world for both. Its impact extends well beyond the walls through more than a dozen programs that serve the environment and the community.
