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How Tampa’s stingrays and penguins died is still a mystery. It may stay that way.

ZooTampa and the Florida Aquarium say they’re still looking for answers. But the public won’t see the ones they’re sending to the accrediting agency.
Among the most popular animal attractions in Tampa are the African penguins at the Florida Aquarium, left, and the stingrays at ZooTampa. The institutions are still investigating mass deaths of the animals in recent weeks.
Among the most popular animal attractions in Tampa are the African penguins at the Florida Aquarium, left, and the stingrays at ZooTampa. The institutions are still investigating mass deaths of the animals in recent weeks. [ Florida Aquarium (2011), Times (2004) ]
Published Aug. 10, 2021

TAMPA — Animals aren’t supposed to die suddenly at zoos and aquariums.

They get constant care from top veterinarians in state-of-the-art habitats. Generally, their life expectancy is higher than their counterparts living in the wild.

But in late May, all 12 stingrays at ZooTampa at Lowry Park died. Seven weeks later and six miles away, seven African penguins at the Florida Aquarium died over the course of a few days.

Together, the incidents snatched away two of the Tampa Bay area’s most popular animal attractions.

Even one episode where multiple deaths might occur would be considered rare.

“I’ve been an animal protection lawyer for 10 years, and I can’t think off the top of my head of a single instance where there was a sudden mass animal death at a facility,” said Christopher Berry, a managing attorney with the Animal Legal Defense Fund.

ZooTampa brought in outside experts and sent water and tissue samples overseas to investigate what killed the stingrays on May 27. They found overnight oxygen levels rose so dramatically in the water that tiny gas bubbles formed in the animals’ bloodstream. It’s called a “supersaturation event,” similar to the bends in humans.

It’s largely unknown, and may always be, what caused the event to occur. ZooTampa’s top aquarist said the tank’s life support systems needed updating but he didn’t blame them for the deaths.

How the African penguins died may also remain a mystery, the Florida Aquarium said, though its veterinary team continues conducting medical tests and evaluations to determine a possible cause. The aquarium has said nothing publicly about the deaths since an initial news release July 8, but answered questions from the Tampa Bay Times last week.

Only three penguins survived, the aquarium said. It didn’t happen all at once. And the deaths put on hold plans to open a new outdoor penguin exhibit — one the aquarium had touted just weeks before on its Facebook page.

Neither ZooTampa nor the Florida Aquarium are obligated to say anything further.

In the case of the penguins, an endangered species, the Florida Fish and Wildlife Conservation Commission is conducting a separate investigation whose findings will be open to the public. Otherwise, the two institutions answer to their nonprofit accrediting agency — the Association of Zoos and Aquariums, based in Silver Spring, Md.

ZooTampa has submitted a report to the association’s Accreditation Commission. Members typically have 30 days to file after an incident. The Florida Aquarium was still working on a report, the association told the Times on Thursday.

ZooTampa declined to make its report available to the Times. The Florida Aquarium said it will release only “documentation of the investigation” and warned that such reviews can take weeks or months.

The Association of Zoos and Aquariums won’t share the reports either, calling them “privileged communication” with its members.

Danielle Horton, a member of the Florida Aquarium, celebrated her daughter’s third birthday with the penguins in September and has always taken note of how the staff deals with them.

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“You can tell those caretakers love and adore these animals,” Horton said.

But as a member of the aquarium, she said, she wants to hear more about what happened.

“I think that they need to come out and say something.”

The animals were already dying

The youngest stingrays were just under a year old. They were named Brownie and Bella.

They were pups of Tracy or Martha, two female Southern stingrays who arrived at ZooTampa from the Florida Aquarium in 2016. They were roughly 7 when the gas bubbles killed them.

Nothing seemed wrong at first. The first caretakers in at around 8:30 a.m. May 27 changed the water like normal.

“It was a typical day,” Tyson Facto, ZooTampa at Lowry Park’s head aquarist said.

But later, when their caretakers came into the exhibit, the stingrays didn’t come to greet them nor eat their shrimp breakfast. When the veterinarians entered a panicked Stingray Bay, the animals were already dying.

In the hours that followed, ZooTampa tried but couldn’t determine the cause of death. The water readings appeared as they should. So water and tissue samples were sent to the Triton laboratory in Dusseldorf, Germany, and the gas bubbles were detected, Chief Zoological Officer Larry Killmar said.

Some type of system malfunction occurred in the hours when no one was there to watch the stingrays, Killmar said. But after weeks of investigating, no one could determine what it was. There are theories, Killmar said — a crack in a pipe, a malfunctioning valve.

Each habitat is largely custom-made, and ZooTampa’s 16,000-gallon pool had equipment described as commonly used in stingray touch tanks. Among the key components were the chiller, 2 or 3 years old, a 4-year-old biofiltration tower, protein skimmers and a sand filter.

ZooTampa spokesperson Sandra Torres said the chillers and protein skimmers were state of the art. Facto said they needed updates. Other equipment like the sand filter needed replacing, he said.

“Technology is always changing,” he said. “There’s other things to look at from when our system was originally put in.”

Not knowing exactly what went wrong, the zoo is tearing down the old Stingray Bay to play it safe, Killmar said. The new $2 million exhibit will have 50 percent more space for the stingrays and will connect with another new saltwater habitat, the zoo’s manatee rehabilitation center, Torres said.

Little federal protection

The Association of Zoos and Aquariums praised the aquarium for being “very transparent with the public about the tragedy with their penguins.”

But the aquarium declined to speak in detail about circumstances surrounding the death of the penguins.

“We are as eager to find answers as you, but we simply do not have any at this time,” spokeswoman Dale Wolbrink said in an email to the Times on July 20.

Still, the sense of loss can be seen now in an outpouring of sympathy on the aquarium’s Facebook page and in stories told there — wedding photos where a penguin named Cliff stands between brides and grooms, penguins waddling through the halls during aquarium anniversary events.

Kim Pagni, 31, of Brevard County, is a penguin lover whose now-husband bought a backstage pass for a penguin encounter in 2015 and proposed to her as the animals surrounded the couple.

Said Pagni, “I was just the most excited I had ever been in my entire life.”

The Florida Fish and Wildlife Conservaton Commission will investigate the penguin deaths to make sure there wasn’t “any neglect or anything that contributed to the deaths of these animals,” Officer Brian Norris told the Times.

The zoo and aquarium have good working relationships with the commission and the commission conducts routine inspections of the institutions, Norris said.

“We rarely, if at all, have any issues with facilities like this,” he said.

The federal Animal Welfare Act offers protection to animals in captivity and is enforced by the U.S. Department of Agriculture. The department is not investigating the deaths of the stingrays or penguins, said Richard Bell, a spokesman for the agency.

“One of the only federal laws that covers wild animals in captivity has a huge gap in that it does not cover so many species of animals,” said Alicia Prygoski, a senior legislative affairs manager with the California-based Animal Legal Defense Fund.

The act lays out protections for warm-blooded animals but doesn’t protect cold-blooded ones. To receive government protection, and trigger transparency of public records, a cold-blooded animal must be classified as a threatened or endangered species. The breeds of stingrays at ZooTampa are not.

The Animal Legal Defense Fund has worked to expand the Animal Welfare Act, passed in 1966, though no proposals are pending before Congress, Prygoski said.

The African penguins are warm-blooded animals, but the Department of Agriculture has historically refused to apply the act’s protections to birds, said Berry with the Animal Legal Defense Fund. Still, African penguins are classified as endangered so they receive protections through the federal Endangered Species Act.

Under the act, passed in 1973, criminal penalties and injunctions can be imposed if anyone is found to have harmed the penguins intentionally or out of negligence, Berry said.

“So it is very prudent to find out what caused the penguins’ death to make sure that additional penguins are not killed through negligence,” Berry said.

He has no reason yet to believe they were, he said.

Mass deaths at aquariums

Mass deaths of animals in captivity are rare, but they happen.

In 2019, more than 30 stingrays died at the Shedd Aquarium in Chicago, according to reports in the Chicago Tribune. Two large-scale stingray deaths occurred earlier, the Tribune reported, at the Brookfield Zoo in Chicago. And 44 stingrays died in 2009 at the Calgary Zoo, according to the Canadian Broadcasting Corp. Also at the Calgary Zoo, seven Humboldt penguins died in 2016.

Caretaking protocols for animals such as stingrays and penguins are established by the Association of Zoos and Aquariums. Member institutions are accountable to the organization if they hope to earn its accreditation.

The association suspended ZooTampa’s accreditation in 2008. The zoo had come under scrutiny after 15 monkeys got away from a private animal park, revealing questionable animal transfers between the park and the zoo.

ZooTampa regained its reputation and is accredited through 2026.

The Florida Aquarium opened in 1995 and received Association of Zoos and Aquariums accreditation in 1997. It has been accredited ever since. Its current accreditation runs through 2025.

Until the shuttered exhibits reopen at the zoo and the aquarium, fans can visit the other institution to see the penguins and touch the stingrays.

At ZooTampa, children squeal as the African penguins slip in and out of the pool, behind the glass panels of an outdoor exhibit. During a visit to the aquarium one weekday this month, some 40 people milled around the circling stingrays for their turn to feel the leathery wings.

It wouldn’t be quite the same for aquarium member Horton, though.

“One of the things that we fell in love with at the aquarium were the penguins.”