MIAMI • Tilikum, the killer whale linked to the deaths of three people and made famous by the 2013 documentary "Blackfish" - which criticised the captivity of orcas - has died, said SeaWorld.

One of SeaWorld's most prominent orcas, Tilikum had been fighting a bacterial lung infection since March. It died at the marine theme park in Orlando, Florida on Friday.

SeaWorld said the approximately 36-year-old killer whale had spent years with the company.

"Tilikum passed away early this morning, Jan 6, surrounded by the trainers, care staff and veterinarians who provided him around- the-clock world-class care," SeaWorld announced on its website.

It noted that Tilikum was near the upper end of the average life expectancy for a killer whale, and faced "some very serious health issues".

The animal rights group People for the Ethical Treatment of Animals tweeted a photo of Tilikum on Friday along with the message: "RIP Tilikum. Dead after three decades of misery." The black-and- white five-tonne bull orca was the largest killer whale in captivity.

In 2010, Tilikum grabbed the ponytail of SeaWorld trainer Dawn Brancheau and dragged her underwater to her death in front of horrified onlookers at the end of a show at SeaWorld Orlando.

Animal rights groups charge that orcas were kept in tanks that were too small, fed improper diets and forced to perform tricks.

Tilikum has also been linked with two other deaths: part-time trainer Keltie Byrne, 21, who slipped into a pool containing Tilikum and two other orcas in 1991, and Mr Daniel Dukes, 27, who sneaked into SeaWorld after hours in 1999.

Under public pressure, SeaWorld last March announced it would stop breeding killer whales, and would no longer keep any of them in captivity after its current generation dies.

AGENCE FRANCE-PRESSE, NYTIMES