Marineland has confirmed to Global News the death of Apollo the walrus.
The themed amusement park and zoo in Niagara Falls says the marine mammal died of a heart attack in late April, according to a necropsy.
“Apollo was in the care of marine mammal staff and veterinarians when he collapsed due to a sudden and unexpected heart attack,” the park said in a statement.
READ MORE: Two deer die at Marineland after father and son allegedly caused a stampede
Attempts by marine experts to revive Apollo were “unsuccessful,” however the release goes on to say the animal “passed very quickly and without obvious pain.”
The death leaves the park with just a single walrus, Smooshi.
In the same statement, the park assured the public that Smooshi is in “good spirits” after taking to the stage for Marineland’s educational presentation on Saturday.
In January, the park revealed that its walrus population dropped to just two after the death of Zeus. Park curators say he also died “suddenly and peacefully” of natural causes on Dec. 26, 2018.
At that time, Zeus was the second walrus to pass in 19 months after a female walrus, Sonja, also suffered a “surprise” death in May 2017, according to the park.
READ MORE: Zoo flamingo has to be euthanized after child hits it with rock
A former trainer, who spent time working closely with the park’s walruses, has sounded off on social media over the past few days.
Phil Demers, who worked with the park for over a decade, said in a Twitter post on Wednesday that the situation for Smooshi “has become more critical than ever.”
“After four recent walrus deaths, she now lives in solitary. Even Marineland can’t deny she needs to be urgently removed and transferred to a better facility,” said Demers.
The death of Apollo comes just days after the park alleges an opening day stampede caused by a father and son resulted in the demise of a pair of deer.
“We are very sad to report that these individuals repeatedly attempted to and were ultimately successful in causing a stampede of deer and laughed in the face of staff as they tried to get them to stop,” the zoo said in a release on Monday. “They refused all instruction by staff and resisted efforts to remove them from the deer park.”
However, Niagara Regional Police told Global News on Tuesday that the deaths of two deer had yet to be reported to police by Marineland.
“The matter was not reported to police. At this time, there is no investigation,” police spokesperson Stephanie Sabourin said in an email to Global News Radio 900 CHML.