Giving a fish a physical exam at the National Aquarium

Vet to sick stingray: "Say 'Ahh"? Not exactly.

How do you give a fish a physical?

If your "patient" is a reticulated stingray with a nearly five-foot-long tail that's covered with needle-sharp barbs, the answer is —

Very, very carefully.

This was the challenge confronting staff members at the National Aquarium on a recent summer morning as they prepared to check the blood work and give an ultrasound to the ray in question, a fetching young female covered with leopard-like spots known as Number 512020.

Each year, about 500 of the 20,000 critters living at the Aquarium get the same kind of annual wellness exams given to humans — though the animals, at least, don't have to put on paper gowns that flap open at the back. Nor could Kat Hadfield, the examining vet, ask Number 512020 to stick out her tongue and say, "Ahhh."

But the vets scan the kidneys and livers of marine animals from dolphins to sea horses to skates. The Aquarium has probes small enough to perform diagnostic tests on fish no larger than your fingernail, and some "lucky" staffers even give dental exams to sharks — a process which can involve mild sedation, turning the animals upside down to make them easier to handle, and special tools that pry their mouths open. (Cue the music for "Mack the Knife.")

Needless to say, some of these procedures involve the approximate level of planning of a minor military campaign.

Before number 512020's exam began, a team of seven marine animal specialists in wetsuits gathered around a small blue tub resembling a child's wading pool. They listened intently as they were briefed by Hadfield and Holly Bourbon, the curator of large fish exhibits.

"Her tail has quite a long reach," Hadfield told the assembled group. "We've taken out the venom, but there are still a lot of short little spikes on that tail. You want to be aware of where it is. Also, she's feeling better than she was the last time we checked her, so she might be a lot more active than she was then."

Bourbon added: "She's stronger. Much stronger."

Everyone glanced over at Number 512020, who was floating several feet below the team inside a triangular-shaped underwater pen. The stingray kept her nose pressed to the gate leading to her watery home inside the Aquarium's Shark Alley, while that dangerous tail pointed in the direction of the humans talking above.

Everything about her body language seemed to say, "Don't mess with me."

As Hadfield tells it, it was a liver and bladder inflammation that got the ray into this pickle. In April, her keepers noticed that she was off her feed. A bit of a diva, 512020 is a picky eater under the best of circumstances, turning up her snout at the fish heads that her less-pampered cousins in the wild happily gobble up.

But when she began losing weight and seemed restless, blood samples were taken and the infection was discovered. The stingray began receiving intravenous injections administered underwater by divers. After she began eating again, meds were mixed into her food. Now, three months later, 512020 was about to be subjected to a follow-up exam.

"It's pretty straightforward," Bourbon said, finishing up the briefing. "We've all done this before. Any questions?"

At 9:05 a.m., Bourbon and aquarists Jackie Cooper and Katie DiCioccio climbed down a ladder and into the pool where 512020 was glumly floating. Bourbon and DiCioccio walked toward the stingray on either side of an oversized blue and yellow stretcher, while Cooper closed off any possible escape routes with what appeared to be a miniature hockey net.

Carefully, Cooper and DiCioccio slipped half of the stretcher under the stingray, and then wrapped the remaining half of the mat over her body, creating the equivalent of a stingray pita pocket. Wooden poles were slipped through flaps on the front and back of the stretcher to stabilize it, and then the entire contraption was chained to an H-shaped metal lift.

"Very nice, very nice, lovely," Hadfield said. At 9:15 a.m., she gave the signal to raise the stretcher.

As soon as 512020 felt her body leave the water, she launched a determined bid for freedom. She struck out with her tail and flopped this way and that, trying to ooze her pancake-flat body out of the small open gaps on the stretcher's sides.

If at times she seemed to have eyes on the top of her head, that's because she does. Rays have oval, otherworldly orbs that lie atop their bodies. When open, each eye looks a bit like a pearl nestled inside an oyster. This positioning allows the rays to keep a lookout for predators even while they're lying on the bottom of the ocean floor, buried in sand.

The team had figured that 512020 could safely be in midair for 30 seconds, which is the time it took the water to drip out of the perforated stretcher, leaving Fishes Research Specialist Alan Henningsen what seemed like an impossibly small window with which to take her vital signs.

"Ninety kilograms," Henningsen said, taking a reading from the scale attached to the stretcher. Hadfield nodded with satisfaction — the ray was gaining weight.

DiCioccio stretched a long tape over the top of the ray and read off her measurements: 147 centimeters wide and 127 centimeters long.

"She's still growing," Hadfield said.

As soon as 512020 was lowered into the blue tank, she quieted right down, though the tub was barely larger than she was. Indeed, her tail trailed for several feet outside the enclosure. DiCioccio occasionally splashed water over the tail to keep it hydrated.

Cooper sat inside the tank with her, her legs resting beneath the ray. She felt along the outside of the animal's jaw. "C'mon, baby girl," she crooned to her.

"Do you remember when we used to do this and you were not such a big girl, and you used to fit into the cookie cutter tub? Do you remember when we used to think we could flip you? We can't flip you now."

Then a second later: "Her teeth feel fine."

DiCioccio wrapped a purple towel around the part of the tail where the most stingers were concentrated, and used it as a kind of handle to turn the fish this way and that as Hadfield ran a probe beneath the ray's belly.

When 512020 passively tolerated these indignities, Cooper planted a kiss on top of her slimy speckled head.

"What a good girl you are," she said. "What a good baby."

By 9:45 a.m., Hadfield announced that she had finished her exam. "We got a respectable amount of blood," she said.

The ray was placed back into the stretcher, hoisted out of the tub and lowered back into her underground pen — this time, without theatrics.

"Good job," Hadfield told the team.

"Her body condition is just right. When we looked at her in May, she had a lot of inflammation in her gall bladder and bile ducts, and that's all gone away. She still has these little areas of scarring in her liver. Those aren't going to get better, but overall, she's doing quite well."

For her part, Number 512020 seemed pleased to be back in her underwater enclosure. She drifted slowly toward the bottom of the pen, blinking her extraordinary eyes.

mary.mccauley@baltsun.com

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