Chicago-area zoo investigates deaths of 54 stingrays

By Suzannah Gonzales CHICAGO (Reuters) - The Brookfield Zoo near Chicago is investigating what caused all 54 of its stingrays to die, a zoo spokeswoman said on Monday. Four southern stingrays and 50 cownose rays died on Friday after the oxygen level dropped in the exhibit habitat, the zoo said in a statement. "We are devastated by the tragic loss of these animals," Bill Zeigler, senior vice president of animal programs for the Chicago Zoological Society, which operates the zoo in Brookfield, Illinois, said in the statement. "Our staff did everything possible to try and save the animals, but the situation could not be reversed." Veterinary and animal care staff responded immediately to help the stingrays, but efforts to get oxygen levels back to normal were unsuccessful, the statement said. Zoo staff members are analyzing the habitat's life-support system to determine what caused the malfunction. "Stingray Bay," the zoo's summer-long exhibit that has operated since 2007, will be closed for the remainder of the season, the zoo said on its website and in the statement. The stingrays were all born in captivity and were kept in a 16,000-gallon saltwater pool measuring about 25 feet by 55 feet, zoo spokeswoman Sondra Katzen said. The pool allowed zoo visitors to touch and feed the stingrays. (Reporting by Suzannah Gonzales; Editing by Eric Beech)