Aquarium Medicine: An Ocean of Possibilities

In veterinary school, Bill Van Bonn, DVM, aspired to be an equine surgeon, a dream he followed into practice. But after a few years, another interest called to him — aquatic medicine — sparked by his years growing up on the Great Lakes. Dr. Van Bonn pursued training in aquatic animal health
and worked for several years with the Navy Marine Mammal Program in San Diego. In 2005, collaboration with a colleague at Chicago’s Shedd Aquarium led to a job offer, which Dr. Van Bonn accepted. Aside from a sabbatical in 2009, he has worked at the aquarium ever since.

The Circuitous Path

Dr. Van Bonn’s indirect route to his current position as vice president of animal health at the Shedd Aquarium is not unusual in the world of aquarium medicine. Greg Bossart, VMD, PhD, senior vice president of animal health, research and conservation at the Georgia Aquarium in Atlanta, started out in small animal practice before embarking on
a career path that included stints at the University of Miami Miller School of Medicine, Miami Seaquarium and Florida Atlantic University’s Harbor Branch Oceanographic Institute in Fort Pierce. Leigh Clayton, DVM, director of animal health and welfare at the National Aquarium in Baltimore, also started in small animal medicine before moving on to zoo medicine. Her experience in avian medicine secured her current position.

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As Dr. Clayton’s story well illustrates, aquarium medicine involves much more than fish. Most large aquariums also feature birds such as penguins
and puffins, various reptiles and amphibians, and mammals ranging from otters and sea lions to beluga whales. Many exhibit terrestrial mammals, as well. “There are so many opportunities to learn new things and work with new animals and apply our knowledge in new and different ways,” Dr. Clayton said. “That always keeps our job interesting.”

The scope of aquarium medicine can be almost overwhelming, considering the species diversity as well as the sheer number of animals on exhibit. “We have about 1,500 different species at Shedd Aquarium,” Dr. Van Bonn said, “and the ballpark total number of animals is around 32,000 — although the reality is, we really don’t know. I could come in tomorrow and there could be 600 new seahorse babies.”

Most aquarium veterinarians spend little time interacting directly with their facility’s collections. That is left to the husbandry departments, which oversee specific animal populations and act as the medical staff’s eyes and ears, notifying them when an animal appears ill.

In certain circumstances, the husbandry staff at Shedd Aquarium train animals to be willing participants in their own health care. “We definitely
rely on the cooperation of the animals,” Dr. Van Bonn said. “Come over and say ‘ah,’ come over and give us your fluke so we can take a blood sample — that sort of thing. And it’s not limited to marine mammals. We have sea turtles that are trained
to get on a scale every month so we can check their weight, and we even have octopuses that are trained to let us inspect their tentacles.”

Training also allows curators and veterinary staff to better understand the animals, Dr. Van Bonn added. Whales, for example, sometimes exhale forcefully — a coughlike behavior known as chuffing. Veterinarians can learn much about a whale’s health and physiology by collecting the chuff and measuring hormone levels and other vital functions.

An aquarium veterinarian’s daily responsibilities are both similar to and very different from those of a community veterinarian, say those in the field. Routine examinations and general animal care take up much of their time but by no means all of it. “Common problems range from vomiting and diarrhea to seizing animals to nutritional problems — issues you would see in a general practice,” Lance Adams, DVM, staff veterinarian at the Aquarium of the Pacific in Long Beach, California, said. “We see a lot of reproduction problems, because trying to manage reproductive issues in a managed population
is a little difficult. We might not have the right sex ratios or the right water quality or the seasonal changes that the animals need to reproduce normally, and that can lead to problems. We try to stay on top of that and be selective with the animals that we acquire.”

Injuries resulting from interactions
in mixed-animal exhibits are another
common issue, according to Dr. Adams.
“During encounters, they sometimes
injure themselves or each other,” he
said, “so we deal often with scrapes,
infections, eye damage — things like
that.” In 2007, a shark almost snapped
off a sawfish’s rostrum at the Aquarium
of the Pacific, requiring the veterinary staff to suture the bite wounds and splint the rostrum until it healed. “It turned out really well,” Dr. Adams said. “That was an exciting case.”

Aquarium veterinarians, like community practitioners, deal with geriatric issues, a happy result of quality care. “In captivity, fish and other animals are protected from food shortages, predation and disease, so we see geriatric problems that we would never see in the wild,” Dr. Adams explained. “For example, animals with arthritis that can’t swim as well are not going to survive very long in the wild, but in captivity, they do. So we deal with issues ranging from arthritis to vision problems to tooth wear.”

Emergent issues are also in a day’s work at the nation’s public aquariums, and some cases become memorable. Dr. Van Bonn once performed complicated knee surgery on a bullfrog (the patient recovered nicely), and Dr. Clayton recalls performing exploratory thyroid surgery on a knob-tailed gecko that resulted in removing a large cyst. The patient was then placed on a thyroid supplement, with the dosage determined by heart rate and shedding frequency because the animal was too small to provide a relevant blood sample.

Among Dr. Bossart’s most memorable experiences: the time his staff worked on an electric eel. “That was interesting because it required considerable care in handling the

animal and putting it under anesthesia,” he said. “Our patients could electrocute us — that was a fascinating concept.”

Indeed, aquarium medicine can be perilous. “Our animals are quite challenging to work with,” Dr. Adams said. “Some of them can be big; some can be strong; some can be dangerous because they are venomous.”

Because little may be known about their patients’ health and physiology, aquarium veterinarians frequently find themselves extrapolating and innovating on the spot. Entire books cover the subject specific to dogs, cats and birds, but no textbooks exist for treating beluga whales, manta rays or electric eels. As a result, aquarium veterinarians commonly confer, sharing information within their small community as it becomes available.

The unusual physiology of the varied species found at most aquariums also requires specialized equipment. For example, a drug called tricaine methanesulfonate, or MS-222, is commonly used to anesthetize fish and amphibians so they can be examined. “This is a critical component to our daily practice and something that most community veterinarians aren’t going to have,” Dr. Clayton said. “In addition, we borrow liberally from all the technology that is used in human and veterinary medicine, and modify it so we can use it on really small creatures and really large creatures.”


Because patients can weigh hundreds or even thousands of pounds, special equipment must be devised for hoisting and transport. At the other end of the spectrum, veterinarians use magnifying devices to examine and work on their smallest patients. Darting equipment, commonly known as jab sticks, is sometimes used to administer medication to species that are difficult to catch or would be too stressed by the attempt.

To promote innovation, Shedd Aquarium partners with the Northwestern University McCormick School of Engineering in Evanston, Illinois, challenging students to create custom equipment that would benefit its animals, such as an enrichment device for otters. When a trainer tosses in a special hollow ball stuffed with shrimp, the otter learns to slide the ball through the plexiglass maze to an opening at the bottom.

Vast Research

Unsurprisingly, research is an integral component at most aquariums, with vast areas of study. Shedd Aquarium’s micro- biome laboratory, for example, has a DNA sequencer that promises to shine new light on unseen organisms, such as bacteria and fungi, that share space with the aquarium’s collections. The National Aquarium received a grant from the American Association of Zoo Veterinarian’s Wild Animal Health Fund to provide the first systemic description of

the blood of horseshoe crabs, an important project because almost nothing is known about the health of these living fossils. The Aquarium of the Pacific is working to help save the severely endangered Guam kingfisher, as well as exploring ways to promote shark reproduction in captivity.

Getting involved

Opportunities for veterinarians with an interest
in aquatic medicine are broad, including large public aquariums, state fish and wildlife agencies, and community veterinary practices that provide services to fish enthusiasts. Interested students and practitioners are encouraged to attend meetings and conferences that emphasize aquatic medicine, and explore opportunities to shadow working aquarium veterinarians.

“This is a great time to become involved in aquatic medicine because there are more and more opportunities,” Dr. Van Bonn said. “It’s a very exciting area of practice.”