An animal rights group says the killer whale at Marineland appears to be sick, but officials insist that Kiska, a mainstay of the Niagara Falls, Ont., water park for many years, is in good health.

Orca United recently sent CBC News photos which it says show signs of a troubling condition known as “peanut head” — an indentation near the blowhole that is a sign of severe weight loss.

This photo, supplied by animal rights group Ontario Captive Animal Watch, purports to show a condition known as 'peanut head' near the blowhole of Kiska, the killer whale at Marineland in Niagara Falls, Ont. (Courtesy of Ontario Captive Animal Watch) CBC News was given access to the park and Kiska. Her trainers say she has “good girth” and eats between 40 and 55 kilograms of fish a day.

Marine mammal supervisor Tom Weston says she's under constant watch by two veterinarians, seven caregivers and a team of 14 outside consultants.

“We check eyes, her breath, we observe every day,” said Weston. “I hope she outlives me.”

Kiska is the only killer whale living in captivity in Canada.

Ongoing protests and complaints about health problems at Marineland were in part what led to sweeping changes to Ontario's animal welfare laws last year.

The OSPCA now does mandatory inspections twice a year. It says it is investigating this new complaint.