Marineland is awaiting necropsy results on a killer whale found dead Oct. 20 -- the second to die at the Niagara Falls, Ont., park since August and the sixth whale death in less than five years.
The death of Hudson, a 6-year-old whale, came as a shock because recent blood work showed no sign of illness, spokeswoman Ann Marie Rondinelli said. It could be some time before tests reveal what killed him, she added. Marineland had closed for the season earlier in October.
In August, Neocia, a 12-year-old killer whale, died in her pool from what turned out to have been an acute viral infection.
Their deaths reduced to four Marineland's orca collection, which occupies a 5 million-gallon exhibit known as Friendship Cove. A separate 3 million-gallon tank holds the park's 20 beluga whales.
The first whale death was in December 1999, when a female beluga died of liver failure caused by parasites the animal had picked up while still in the wild. The second, about 10 weeks later, was a 3 1/2 -year-old Orca whale who was born with a deficient immune system and had been on medication most of her life, park officials said.
In August 2000, a young female beluga died of a brain hemorrhage after a petting session. Two years later, a killer whale calf born at Marineland died unexpectedly. None of these whale deaths was caused by neglect or poor medical care, and the beluga collection has grown rapidly, Rondinelli said.
"We do all we can to keep the animals heathly. They get regular blood tests and good-quality food," she said.
In the past, Canadian animal rights activists have criticized Marineland's ownership of killer whales and belugas, which they say belong in the ocean.
But the 42-year-old park maintains that allowing the creatures to be viewed up close serves to educate the public and will help protect the species.