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This article was published 26/6/2019 (212 days ago), so information in it may no longer be current.
The Assiniboine Park Zoo has temporarily closed its popular Stingray Beach exhibit after three of its 27 rays died due to aggressive mating behaviour.
The zoo’s director of veterinary services, Chris Enright, said Wednesday an uptick in breeding activity earlier this month is to blame for the deaths of the cownosed rays.
Three others were injured, the zoo said.
It is natural for rays to be aggressive during mating, Enright said. Males chase and fight each other to compete for mates — just like their relatives, sharks. Mating is violent, as well.
"The actual breeding act itself consists of males chasing females, and there’s biting along the wings and back as part of that natural mating behaviour," Enright said.
In an attempt to stop the animals in the open-tank display from injuring each other during such times, zoo staff will try to cool things down.
Caretakers will reduce the water temperature and the rays’ exposure to light so the animals will think it’s winter, Enright said. The breeding season usually lasts from April till June.
"In human care, where we can manipulate day/night cycles, sometimes it can go for longer," Enright said. "In this case, we are trying to curtail it entirely."
If those interventions don’t work, the next step could be separating males from females, he said.
“We have seen a lot of positive improvement, even in the past 24 hours. We have seen response to care. We do take it day-by-day.” – Zoo director of veterinary services Chris Enright
The three injured rays are recovering. "We have seen a lot of positive improvement, even in the past 24 hours," Enright said. "We have seen response to care. We do take it day by day."
One is in isolation to ensure it receives its antibiotics, he said, adding the ray received full anesthesia for an exam and an ultrasound, among other diagnostic tests.
"It looks like the same standard of care a person might receive in a hospital, only in the water instead of a bed."
The popular exhibit, which opened in May, allows visitors to touch and feed the rays.
Enright said there’s no indication that human touch has contributed to the rays’ rough behaviour.
"It is observed in wild sharks and rays, as well as those in human care. But those in human care have us, who can intervene. And that’s what we’re doing today."
Volunteers will be posted outside the exhibit to warn people away; the interactive display won’t reopen until officials are certain the aggressive activity has cooled off.
"Stingrays, they are engaging, they are absolutely a fantastic creature, they are a great way to connect with the ocean environment in a situation that is pretty far removed from the ocean, here," Enright said.