Two sea lions that died at the Aquarium of the Pacific apparently succumbed to heat exhaustion, aquarium President and Chief Executive Jerry Schubel said Monday.
Kona, 4, and her 4-week-old pup died in their shaded nursery at the Long Beach facility Saturday afternoon. Both had above-normal liver temperatures and signs of thermal shock in other internal organs, Schubel said.
"We're so baffled that heat exhaustion could have caused their deaths because the temperature wasn't any different and we were following the same protocol," Schubel said. "We're investigating whether there was something that made them more active."
Both mother and pup appeared healthy during their cool-water bath earlier Saturday but were found motionless by a staff member an hour later.
According to aquarium staff, the temperature near the nursery was about 89 degrees, one degree higher than the previous day, and it was 94 degrees in the back portion of the aquarium.
The loss of Kona and her pup came within 24 hours of the death of 7-year-old Roxy, who came to the aquarium as a pup after being abandoned during an El Nino storm.
After giving birth to a stillborn pup the previous night, the sea lion died from a reaction to anesthesia administered during emergency surgery.
Two sea lions remain at the aquarium.
Kona gave birth to her pup, the first to be born at the aquarium since it opened eight years ago, over Memorial Day weekend.
Two weeks later, the two were moved from a special area near the sea lion exhibit to a behind-the-scenes nursery.
All seals and sea lions are checked hourly around the clock and receive regular blood work-ups, Schubel said, but a staff mammalogist and veterinarian are now inspecting the animals more often.