CALGARY — Another four stingrays have died at the Calgary Zoo, bringing to 39 the number of creatures who have died.
The deaths mean there are only four survivors out of the original 43 cownosed rays in a water exhibit that allowed the public to touch the creatures.
Independent test results have also been released that show the pool's water chemistry was safe for the health and well-being of the stingrays.
A spokeswoman says the tests confirm earlier ones done on-site that checked levels of ammonia, dissolved oxygen, salt content and a number of other natural minerals.
But the zoo stressed the initial tests are not able to identify possible toxins — water samples and tissue from the dead rays have been sent to specialists who can screen for that.
It's not been determined what killed the stingrays, although the zoo has not ruled out that a foreign substance was added to the water.
