ZooTampa has determined that a “supersaturation event” that caused a fatal gas bubble disease killed the 12 stingrays in its exhibit on May 27.
The zoo, however, does not know what caused the event. ZooTampa believes a system malfunction or cracks in the pipes could be possibilities.
According to a ZooTampa news release Tuesday, the gas bubble disease is similar to “the bends” in human scuba divers — caused by bubbles in the blood stream.
Supersaturation is when an amount of substance in a solution exceeds what is necessary. In this case, there was a high level of oxygen in the tank, causing the gas bubble disease in the stingrays.
The zoo believes the event occurred overnight and was not immediately known because the oxygen levels had returned to normal when the water was tested that morning.
ZooTampa will not reopen the 16,000-gallon exhibit, and instead will build a new one with a new, updated water management system.
All 12 deaths happened suddenly, and initial tests did not reveal anything wrong with the water.
ZooTampa’s investigation report revealed the water had a standard change that morning, eliminating the harmful oxygen presence overnight. That water change happened after the damage to the stingrays health was already done.
Last week, ZooTampa said it had sent water and tissue samples to Triton labs in Dusseldorf, Germany, and brought in two aquatic experts in the zoo and aquarium industry to study the stingrays’ deaths.
ZooTampa spokesperson Sandra Torres said the investigation was expected to take several weeks. This report came back less than one week after her statement.
The 12 stingrays included seven cownose stingrays, four Southern stingrays and one Atlantic stingray.
This is a developing story. Stay with tampabay.com for updates.