Calgary Zoo loses another stingray

Calgary Zoo officials said another stingray died over the weekend, more than a week after the zoo's rays started dying suddenly and mysteriously, leaving just two.

In a release dated Tuesday, officials said the smallest of the rays remaining on the weekend had died.

The ray exhibit opened in mid-February, after the rays were shipped in from Florida. Starting in April, visitors were able to touch and feed the creatures.

The rays started dying on May 11, when after a public visit, the keeper noticed some of the cownose rays were swimming erratically and seemed distressed. By the following morning, 34 rays were dead. An additional six rays died over the course of the next two days, bringing the deaths to 40. The latest death means that 41 of the zoo's 43 rays have died.

Zoo veterinarians said in the release that the two surviving rays "seem to be improving slowly."

The zoo, with police assistance, continues to investigate. Officials have speculated that a small quantity of a toxin in the water, such as an herbicide or pesticide, could be responsible.

Test results released last week showed the water chemistry of the pool was within the appropriate ranges for the ray's survival, but were not able to identify possible toxins in the water.

The zoo said while they may receive some preliminary results from tests on water samples and tissue from the dead rays this week, final toxicology results are not expected for several weeks. The exhibit will remain closed until further notice.

Zoo keeper recovering

The latest death caps off a tough weekend for the zoo, during which time a senior elephant keeper was injured by one of the pachyderms.

Brent Vanhooft, 48, was knocked down by Swarna, a 34-year-old female elephant, on Sunday and sent to hospital with cuts and bruises on his face.

The zoo said he was pushed from behind while cleaning the floor in the area where Swarna was standing. Officials said Swarna may have been trying to protect a nearby nine-month-old calf named Malti.

The zoo said Tuesday that Vanhooft continues to recover at home and is expected to return to work within the next week or two.