Jeff DiVeronica

@RocDevo

They named the sea lion pup born in June "Sunny" after 1,700 suggestions poured into the Seneca Park Zoo, but there is a dark cloud over the zoo. Officials announced Monday that Sunny died unexpectedly Dec. 12 for reasons they still don't know. It's the third sea lion death there in the past four months.

"We share the same questions ... could they somehow be connected? The evidence at this point says no," said Dr. Jeffrey Wyatt, the zoo's director of animal health and conservation.

Sunny's mother, Marina, died in September and Boomerang, a 10-year-old male, died in October. Zoo officials say based on their findings the deaths are unrelated, but "we want to make sure we're not missing anything," zoo director Larry Sorel said. It has asked the Association of Zoos and Aquariums and the U.S. Department of Agriculture to review the sea lion program and its Rocky Coast exhibit, which opened in 1997. Sorel hopes that will take place next month.

They want to make sure everything is as it should be in Rochester. The Seneca Park Zoo was most recently accredited by the AZA in 2013. That accreditation lasts five years, through 2018.

"We have a diagnosis on (Marina), which is epilepsy, the second one (Boomerang), which is heart failure, and it will take probably four weeks," for histology results on Sunny to arrive.

One sea lion remains at the zoo. Her name is Lily. She arrived in 2009 after suffering an injury to her right front flipper while in her natural habitat. Sunny died in mid-morning. Only moments after entering the exhibit's water, she was found unresponsive at the bottom. An employee rescued her from the cold water, but an attempt to resuscitate her was unsuccessful. Wyatt said the tried CPR for 15 minutes.

A necropsy, or autopsy for animals, suggested no obvious cause of death, Wyatt said, but just as with Marina and Boomerang, further analysis will be done by an independent wildlife pathology laboratory. Boomerang's cardiac fibrosis, which caused congestive heart failure, was found only after microscopic examination of his heart tissue.

"We are very comfortable with our program and certainly very confident of the staff and everything they’ve done," Sorel said.

Seneca Park Zoo's sea lion Marina dies unexpectedly

Boomerang was 10. Marina, who appeared to suffer a seizure before dying, was 7. Sorel said that while it varies, the average life span for most sea lions in zoos or captivity is teens or early 20s. Boomerang and Marina arrived in Rochester as rehabilitation animals. Marina had only one eye because of a gunshot, Wyatt said. He added that although sea lions are protected mammals "some (people) on the West Coast find them as nuisance animals."

That trauma could have contributed to what ever triggered her seizure. Wyatt said it's possible, because of genetics, that Sunny could have had a seizure. No one saw anything odd happening that morning until she was located at the bottom of the pool. Pathology results may tell more. Sunny's necropsy turned up only two things of note. Wyatt said she had "dark lungs," but that likely was the result of the extensive CPR.

There also were 0.8 ounces of foreign substances — small pieces of cement, six "small wires," and a grommet — inside her. "There were no stomach lesions, no perforations, no reason to believe that foreign amount contributed to her death," Wyatt said.

Zoo's sea lion pup dubbed 'Sunny'

Sunny's name fit because, like usual, the morning of her death she was "bright, alert, playful," Wyatt said. She had adapted well since her mother's death, being weaned off milk to live fish so well that she'd topple people in the way of her and handlers ready to feed her.

A very social mammal, Sunny also connected well with Lily. Zoo handlers refer to her as Sunny's "Aunt Lily." Employees are showing Lilly extra attention, officials said, until they can bring more sea lions to Rochester. They'll explore that with other zoos and rehab facilities after the AZA and USDA's reviews, Sorel said.

Sea lion pup born at Seneca Park Zoo

The sea lion exhibit is one of the zoo's most popular. While Rocky Coast opened 20 years ago, the zoo has had sea lions for more than four decades, Wyatt said.

"Our mantra is to be transparent … be it a small frog that might pass away to a larger animal that is higher profile, we take the same approach," Wyatt said. "We recognize that this series of (deaths) would raise questions understandably and that’s why we’re here sharing information that we know and where we’re going with fact-finding."

JDIVERON@Gannett.com