Brookfield Zoo officials hope to know by the end of the week what caused a life-support system malfunction that led to the deaths of 54 stingrays in the zoo’s popular Stingray Bay exhibit on July 10.

 “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, said in a press release. “Our staff did everything possible to try and save the animals, but the situation could not be reversed.”

During a telephone interview on Monday, Ziegler confirmed that the zoo was investigating what went wrong.

 “We have absolutely no idea what happened,” Zeigler told the Landmark. “Beginning [Monday], we will start going through and testing every component. By the end of the week we’ll know where we’re going.”

 The long-term future of the exhibit is unknown. For the short term, officials have closed the summer-long temporary exhibit for the remainder of the season. Signs announcing the closing have been posted at the north and south entrances of the zoo and at the exhibit itself. Officials have taken down information about Stingray Bay from the zoo’s website, replacing it with notice of the closing.

 Ziegler said response from the public has been supportive.

 “We have a huge Facebook following and social media response has been overwhelming,” he said. “Most people have commented on how much they enjoyed the exhibit and interacting with the animals. However, they are really sad.”

 He described the zoo as a family, including the animals, and noted how staff members have been affected by the deaths of the stingrays. The public is apparently aware of that family feeling as evidenced in the number of Facebook postings from people offering their condolences to staff members, according to Zeigler.

 This is the second tragedy to strike Stingray Bay since it opened in 2007. In 2008, an increase in water temperature caused the deaths of 16 stingrays, an incident Zeigler described as unrelated to what happened Friday.

A private company operated Stingray Bay in 2008 and the exhibit included sharks and horseshoe crabs. Since reopening, the zoo has operated the exhibit and only stingrays are featured.

 Stingray Bay, which is open from April or May through Labor Day, has been the zoo’s most popular attraction for the summer, attracting 211,000 visitors in 2014, according to Sondra Katzen, the zoo’s media relations manager.

 Zoo staff members were alerted to a problem when an alarm went off on the afternoon of July 10. After determining remotely that the oxygen level in the stingrays’ tank was deficient, staff members responded to the exhibit, where they noticed the stingrays’ behavior was abnormal.

Although oxygen levels were restored within 20 minutes, four southern stingrays and 50 cownose rays died. The majority of the deaths occurred Friday afternoon although several did not die until that evening.

“It’s a sad day today,” Katzen said.