St. Louis (KSDK) -- Multiple factors contributed to the deaths of three seals, Saint Louis Zoo spokesperson Susan Gallagher said in a press release.
The primary cause was that the seals had extertional myopathy, a disease of a muscle. Severe cases of myopathy are characterized by stiffness and acute renal failure and may develop under stress.
"Essentially it appears these animals were not used to being in a transit situation," said Dr. Eric Miller, DVM, Senior Vice President and Director of Zoological Operations at the Saint Louis Zoo. "Contrary to some claims, the necropsies yielded no evidence that external heat stress was a factor in the death of the seals."
The three seals were part of a shipment of four adult harbor seals coming from Canada to join 11 sea lions in the Saint Louis Zoo's new, 1.5-acre Sea Lion Sound exhibit, which opened June 30. The remaining seal arrived in St. Louis on June 9.
The seal completed her quarantine period at the zoo and has been moved to the new exhibit.