An ailing 12-year-old dolphin that was part of SeaWorld's stable of underwater mammals died last week — becoming the fourth death since last summer, said park officials in San Antonio.
A necropsy is being done to determine how Dart died, SeaWorld said in a blog post. The male Pacific white-sided dolphin had been in the park's care since 2003.
"Dart had been monitored for health-related issues for about a month and was under constant veterinary care," said SeaWorld, adding that he was with his two dolphin companions, Betty and Hailey, and caretakers when he died.
Betty, at age 37, is the oldest Pacific white-sided dolphin at SeaWorld San Antonio. The species can live for over 40 years, according to the National Oceanic and Atmospheric Administration.
"She is currently under 24-hour veterinary care for indications of inflammation or a possible infection," SeaWorld said.
Dart's death comes after a series of animal deaths at the park: a newborn beluga died last July after being born premature; a 2-year-old beluga whale died in November after suffering gastrointestinal problems; and a killer whale died in December from a bacterial infection, reported the San Antonio Express-News.
PETA, which has called into question the deaths and SeaWorld's practices, said in a statement to the newspaper that the latest incident highlights how the dolphins should be in a proper seaside sanctuary.
SeaWorld San Antonio is planning an expansion that will provide a new habitat for its bottlenose dolphins.
Instead, PETA claims, the parks is planning to open "yet another dolphin tank that will sentence more of them to a sad life and possible early death."