Canadian zoo investigates puzzling stingray deaths Posted on May 17th
remained baffled on Tuesday as they tried to puzzle out just
why 34 of their stingrays suddenly died.
The juvenile cownose stingrays, about the size of a dinner
plate, were kept in a “petting” tank where visitors were able
to touch them, a common feature in a number of North American
zoos and aquariums, according to the zoo officials in the
Western Canadian city.
On Sunday, within a few hours of opening, the normally
voracious fish lost their appetites, became discolored and
started dying, with 34 of the 43 rays quickly succumbing to an
ailment or cause that has yet to be diagnosed.
“It was a very acute onset of something, a very sudden
change,” said Cathy Gaviller, director of conservation,
research and education for the Calgary Zoo. “It was high
mortality in a very short period of time.”
The zoo, as yet, has no real idea of what happened to the
rays, which are common in the waters off North America’s east
coast.
Water tests show there were no problems with the tank or
its filtration system, though the zoo has also sent off samples
for independent testing.
Gaviller said that because of the speed of the deaths,
disease or parasites were unlikely causes, but nothing is being
ruled out. However results from tissue and toxicology tests
won’t soon be ready.
“It’s unfortunate that we have very few facts,” she said.
“But the No. 1 likelihood is that something in the water
changed suddenly.”
She added that there were no signs that a zoo visitor
caused the rays’ deaths.
The incident is the latest in a number of animal deaths at
the zoo that have sparked criticism of the facility.
A hippopotamus being moved to Calgary from Denver,
Colorado, died in October. As well, a baby gorilla died in
August after other gorilla disrupted the mother’s nursing
routine.
(Reporting by Scott Haggett; editing by Rob Wilson)
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