Researchers are asking people to keep an eye out for three endangered orcas that are presumed dead, saying a necropsy could shed light on what killed them.

The U.S.-based Center for Whale Research announced Tuesday that J17, K25 AND L84 had not been seen in months and are now presumed dead.

All three were well-known to both Vancouver Island experts and residents as they frequented the Salish Sea during the summer. 

Anna Hall, a Victoria marine biologist, said when she heard the news she thought "Oh no. Not again."

Images taken from previous months showed J17’s body deteriorating due to a condition known as "peanut head," but Hall was hopeful she would make a comeback. 

“Animals sometimes can come back, but when they reach the point J17 did and when we saw she had peanut head…that is a condition I don’t think I have ever seen a killer whale come back from," she said.

Hall had been watching and studying J17 since the early 1990s. 

“She was one of my very favourite whales, I had seen her for several decades. Watched her grow up and have her calves and see her family grow,” said Hall.

There are now only 73 southern resident killer whales left.

A biologist at the Centre of Whale Research in Vail, Wash. said the loss of all three is tragic and sad.

“From the perspective of conserving the population we just lost two potential breeding males who could really help with the genetic diversity of the population, along with an older female who was proving her knowledge and experience,” said Michael Weiss.

Other larger mammals, such as humpback and grey whales, are seeing their populations rebound in the same waters as the southern resident killer whales.

“We see harbour seals regularly in the winter, we see the sea lions regularly into the spring, grey whales have made a recovery, humpback whales we know are on the increase,” said Hall. 

“There are very many positive ecological stories taking place.”

Hall said figuring out the mystery around why southern resident killer whales are in decline is fundamental for their survival.

“It is time to expand our human perspective and our recovery actions to not just our local waters but the full range of southern resident killer whales,” said Hall.

Other experts blame the presumed deaths on the lack of food. Advocates have long decried a lack of Chinook salmon in Pacific waters as a reason behind their declining numbers, and the federal government announced fishery closures in B.C. earlier this year in a bid to conserve the key food source.

“It is a history of not taking care of salmon-spawning habitat,” said Weiss. “It's part of a pattern, it is not a one-off tragedy. It is part of an ongoing tragedy.”

A history professor at the University of Victoria, Jason Colby, said the whales cannot move, hunt or reproduce right now with the current amount of food.

"That is really, fundamentally the issue," said Colby. "They need space, food and time and that is only going to come from us making hard choices for them."

Vancouver Island residents are being asked to keep a lookout for the carcasses of all three whales so scientists can determine exactly how they died and maybe learn more about save the beloved species. 

“If you do find a whale on a beach please report it in to DFO so that the scientist can get as much information as possible before the window of opportunity closes,” said Hall. 

If a whale is spotted, you are asked to call BC Marine Mammal Response Network at 1-800-465-4336.