Necropsy reveals orca killed near N.L. was healthy male, but DFO wants more answers

Jack Lawson/Twitter

The carcass of a killer whale is giving Dr. Jack Lawson some answers about marine life off the coast of Newfoundland and Labrador — but he still has more questions.

The exact age and diet of the whale are still unknown, although it's been determined that it had few health problems.

"It was just a very healthy individual that had happened to blunder into a net," said Lawson.

The killer whale drowned last month off the coast of Beaumont, Notre Dame Bay after becoming entangled in a gill net. The carcass was taken to a laboratory in St. John's for Lawson and his team to analyze for the Department of Fisheries and Oceans.

So far, the necropsy has revealed several things.

"It had a good layer of blubber. We went through all the organs and there was no evidence of tumours.… The teeth were very sharp and fresh," said Lawson.

We're not really sure what we have here in terms of who eats what. - Jack Lawson

He also said that the age can be roughly narrowed down to sub-adult, due to the size of the orca's dorsal fin. 

"The dorsal fin was only 1.3 metres tall. So a fully adult male killer whale would be about 50 per cent bigger than what this one was."

"My estimate on this animal is that it might be eight years old, perhaps 10 years old," he said.

To obtain an exact age of the whale, Lawson said he needs to wait for a certain tool.

He said that it's possible to find the age of a whale by cutting one of its teeth in half and counting the rings inside, like a tree. Unfortunately, the saw that Lawson's team had was too small. 

"We just can't get it to work with these big teeth. So we're in the process of trying to get a larger size."

What we don't know

Todd O'Brien/CBC

Lawson said studying the whale would give him an opportunity to learn more about the eating habits and food chain of orcas and other marine animals in the oceans surrounding N.L.

So far, much of that information has yet to yield itself.

"One of the questions we have around Newfoundland is, relative to, say, British Columbia, where the killer whale group there is quite well known for many years of study.… We just don't have that same sort of information," he said.

"So we've seen whales that have been observed killing and eating minke whales, attacking dolphins, that kind of thing. But we've also seen the same killer whales, and as well different killer whales, also feeding on things like … mackerel and herring." 

"So we're not really sure what we have here in terms of who eats what," said Lawson.

The orca's intestines didn't reveal any evidence to help answer this question. Lawson said that nothing was found that looked obviously like "a prey item."

He said the orca's fecal matter is being sent to a lab on the mainland to try to determine the whale's diet.

As for now, Lawson said he's just relieved that the dead orca wasn't a female.

"I would be even more concerned if we'd lost a female. You only need one male and a bunch of females in a pod of killer whales to keep things going along. So if it had to be an animal that died, I guess a male is kind of better."

Read more from CBC Newfoundland and Labrador