jeff_dudas
Joined: 30 Jun 2004
Posts: 752
Location: Miami, Florida
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 Posted: Tue Sep 13, 2005 6:19 pm Post subject: Shark mystery: Aquarium discovers lumps caused by swallowin |
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Several of the sand tiger sharks at the Maritime Aquarium at Norwalk were X-rayed
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Shark mystery: Aquarium discovers lumps caused by swallowing gravel
By Ryan Jockers
Staff Writer
Published September 13 2005
NORWALK -- The volunteers were asked constantly: Is that shark pregnant?
No, they'd say, because it's male. Then why, would come the inevitable follow-up, does it look like he's swallowed a bowling ball?
It's a good question -- one that took the Maritime Aquarium at Norwalk about eight years to answer.
One of the oldest sand tiger sharks in the aquarium's Open Ocean Tank is an 8-foot-long male, which developed an unsightly protuberance on its underbelly about eight years ago.
The aquarium staff wondered: Was it a hernia? Fluid? They asked staff at other aquariums if they had seen anything similar, and no one knew. After a few years, the lump disappeared.
Then, in December, after a few horseshoe crabs and stingrays were added to the tank, the lumps reappeared in four of the sharks. And as mysteriously as they reappeared, the lumps disappeared in two sharks and remained in the other two.
Aquarium staff considered that the sharks might have eaten the horseshoe crabs and sting rays, but couldn't tell whether there were fewer of those animals in the tank because they're good at hiding. Staff members were stumped.
"So we began to aggressively consult with other aquariums," said John Lenzycki, the aquarium's assistant curator.
They sent digital photographs to various shark researchers and veterinarians nationwide, none of whom had seen the condition nor could offer a recommendation.
Finally, a veterinarian at the Wildlife Conservation Society recommended a former colleague, Barbara Mangold, who researched white sharks in South Africa. Mangold, it turned out, was working nearby, at the South Wilton Veterinary Group on Route 7.
000200000D0D0000085E D07,Mangold was interested and recommended an X-ray and sonogram be taken. She connected the aquarium with the Fairfield Equine Clinic, of Newtown, which had a portable X-ray machine that was brought to the aquarium March 16.
Handling the smaller of the two sharks with a lump -- a 4-foot-long sand tiger being more manageable than an 8-foot-long one -- the aquarium staff and the equine veterinarians examined the bulge. "It felt like there was a bean bag in its abdomen," Lenzycki said.
The X-rays and sonograms showed a deposit of gravel in what appeared to be the shark's spiral intestine, at the end of its digestive tract. The staff pondered whether the shark had been ingesting gravel while picking up food from the tank's bottom.
But to determine the exact location of the gravel in the shark required further, manual investigation: Someone had to put their arm into the shark's mouth and feel around its stomach.
"We took a 4-inch pipe, wrapped with a towel, to give the teeth something to snag on, and then we reached through the opening made by the pipe," said Jack Schneider, the aquarium's curator and education director. "It's something we all do."
They didn't find the gravel, and concluded it was in the shark's intestine. The experience seemed to upset the shark, however.
The lump shortly disappeared, presumably because the shark was too distressed to eat. It reappeared when the shark regained its appetite.
The sharks pass the gravel through their systems and eat enough of it to sustain a lump, Schneider said. He said they seem to have become habituated to eating it.
But the aquarium staff still wondered, as Lenzycki said: "A lot of aquariums have sharks in tanks with gravel, why ours?"
As much as sharks have been studied, the aquarium curators said much of their behavior remains unknown; they speculated that their sharks' behavior is mirrored in the shadowy depths of the ocean.
Still, they said, the lumps are "not aesthetically pleasing" and prompt an endless line of questioning from visitors, so they would like to see them gone.
At the same time, the sharks are healthy, so they don't want to do anything to hurt them.
To dissuade the sharks from eating gravel, aquarium curators placed a Fiberglas grate over the gravel, allowing the rays to suction the food from the bottom and, theoretically, prevent the sharks from ingesting the gravel. But the lumps remained.
The aquarium also tried feeding the rays smaller, less noticeable pieces of fish, but that hasn't worked either.
The lumps briefly disappear but ultimately return. Late last week, a few of the aquarium's sharks appeared to have swallowed bowling balls.
The staff is considering giving the sharks a food suppressant, but must explore the effects of such an action further before making a decision.
"The conclusion is that the animals don't seem to be under distress," Schneider said. "It's an aesthetic concern, for sure, but there's only certain lengths we'll go through to deal with it since it doesn't seem to be affecting their well-being."
Copyright © 2005, Southern Connecticut Newspapers, Inc.
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source: http://www.stamfordadvocate.com/news/local/scn-sa-sharks1sep13,0,4870468.story?coll=stam-news-local-headlines
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