A failed pregnancy led to a bacterial infection that claimed the life of an endangered killer whale off Vancouver Island earlier this month, says a Fisheries and Oceans Canada specialist.
The orca known as J-32 was found floating near Comox, B.C., Dec. 4 and a necropsy was performed two days later. The whale was a member of a population that lives in the waters off B.C and Washington state.
Preliminary necropsy results show the orca was pregnant with a "very large" female calf that died at least several days earlier, said marine mammal co-ordinator Paul Cottrell in an interview Tuesday.
"The unfortunate thing, as well, is that it was a female calf, which really would have contributed to the population going forward," he said. "So it's kind of a double whammy there."
Only 77 orcas remain in the population and there has not been a successful birth in at least two years.
Cottrell said the infection likely originated with the calf before spreading to the mother.
He said the calf weighed 175 kilograms, and it was too soon to say whether the orca suffered long-term starvation.
"With the calf dying in the womb, of course J-32 was in distress," he said, adding it's unlikely the mother fed for several days because of the infection and dead calf.
Cottrell said the federal department continues to investigate because teeth were removed after the orca's necropsy, but he said he had no new information to share.
Tissue samples from the necropsy will be sent to eight laboratories across Canada and the United States. Cottrell said scientists hope to learn more in the coming weeks and a final report is expected in the spring.
Ken Balcomb, a scientist with the Center for Whale Research in Washington state, assisted in the necropsy and said he believes toxic pollutants and a lack of salmon contributed to the orca's death.
There are not enough Chinook salmon for the orcas to eat and they are metabolizing their blubber fat, which contains environmental contaminants, he said.
Balcomb, who has been studying this orca population for 40 years, said that J-32's intestines were empty, meaning she hadn't eaten for a week or more.
"I think the solution is to make sure we have plenty of food available so they don't have to metabolize their fat stores to survive," he said.
"We're on a downhill trend that's actually accelerating because we're losing young reproductive females that should be providing four or five calves in their lifetime," he said, adding the death is a stark warning.
Cottrell said contaminant levels in the orca's blubber would be examined as part of the "very thorough" ongoing testing.
"We want to learn from this animal," he said. "We're going to look at all the issues around the samples and gather as much baseline data as well as other information that we can from J-32 and also her calf. It's very important and we're doing a very thorough look at this."