A dead female orca calf was discovered at Mussel Beach on Dec. 23.
“The teeth weren’t erupted on this calf so it was quite young,” DFO Marine Mammal Coordinator Paul Cottrell told the Westerly News.
“Typically that means that it’s likely under three months of age…Of course there’s exceptions to that but we know it’s a relatively young animal for sure.”
He said the animal weighed 158 kilograms—adult female orcas typically weigh around 4,000 kilograms—and the fact she was a female makes the tragedy especially concerning.
“Females are so important because they’re the ones that are going to produce the calves that contribute to the population, the males are important socially but females are the ones, I think, that are especially important,” he said.
Officials don’t yet know which population the young orca belonged to. British Columbia hosts four known populations: southern residents, northern residents, transients and offshores.
Southern residents are listed as endangered under Canada ‘s Species at Risk Act with the other three populations listed as threatened, according to Cottrell.
“All populations have special protection, action plans, and recovery strategies that are put in place to try to help these populations recover,” he said.
“They’re very, very, different populations and they don’t tend to interact but they all are important and they all have limited numbers and we’re looking for recovery of those species so whenever we get a dead calf, regardless of which population or ecotype, it is important that we figure out what happened.”
The endangered southern residents celebrated a baby boom in 2015 with eight new calves marking the population’s highest number of offspring produced since 1977.
Cottrell said early evidence suggests the orca found on Mussel Beach was not one of the eight and he noted a group of transients had been spotted swimming near Ucluelet around the same time the dead female was discovered.
“Killer whales were around the area for quite a few days overlapping this and those were identified as transients so we don’t know for sure but this calf coming to shore overlaps with that group of transients that were in the area,” he said.
“We’re still going to wait for the DNA because we’re not sure.”
Photos of the calf were compared to photos of the eight new southern resident babies and no match was found, according to Cottrell.
“They couldn’t find a match so I guess that’s encouraging but really any killer whale calf from any of the populations dying is not good news,” he said.
“Having said that, killer whale calves have fairly high natural mortality rates in the first year, it can be up to 50 per cent, so it’s not unexpected to have a death but we want to know what the cause was.”
Cottrell hopes the results of a necropsy conducted on Dec. 25 will determine what population the orca belonged to and why she perished.
“It’s going to take months to get all the tissue and all the results back but there was an infection that was identified so we’ll hopefully know what bacteria or pathogen that was and work back at how that was related potentially to how the animal died,” he said.
He suggested the necropsy was successful because the surfer who first spotted the orca on Dec. 23 immediately reported his sighting.
Tofino-based fisheries officers Dan Smith and Heather Bettger arrived at the site the next morning and, with the help of equipment provided by the Mussel Beach Campground, were able to transfer the whale onto their fisheries truck, according to Cottrell.
“The animal had been scavenged on by coastal wolves; it’s amazing how quickly they can sniff out a marine mammal carcass,” Cottrell said. “Without [the surfer] calling this in, we may not even know the animal was there. The wolves would have known, which would have been okay for food but we probably wouldn’t have been able to determine what happened.”
Smith and Bettger drove the calf to Nanaimo where they transferred her to Cottrell who traveled with the animal on a BC Ferry out of Duke Point and delivered the orca to provincial veterinary pathologist Dr. Stephen Raverty late at night on Christmas Eve.
“It was bang-bang, within a day-and-a-half from the beach to the table where Dr. Raverty did his thing, took all the samples and measurements,” Cottrell said.
Raverty and a UBC researcher conducted the necropsy on Christmas Day.
“He spent his Christmas doing a necropsy on a killer whale instead of carving up a turkey; he’s an amazing, amazing, person,” Cottrell said of Raverty.
“He got the job done, which was just amazing given the time of year and how we were all able to put it together shows the passion and the commitment from the BC Marine Mammal Response Network members.”
Cottrell urges anyone who sees a distressed or deceased marine mammal to immediately report the sighting to the BC Marine Mammal Response line at 1-800-465-4336.
“The tissues degrade so fast, even when it’s fairly cold out, so getting the animal’s carcass on the table to do the necropsy immediately is really important,” he said.
“The quicker we can get these to the lab the more information we’re going to get from the carcass and it could be something that’s really crucial or there could be something emerging in the population and, if we can find out what that is, that’s so important to make sure it doesn’t get out of hand or we can look at what we may be able to do to prevent something from spreading.”