The death of a pregnant orca off the B.C. coast has highlighted a unique set of challenges threatening the dwindling population of southern resident killer whales.
According to a preliminary necropsy report, Rhapsody the orca died while ridding her body of an already-deceased calf, and she appeared weakened by a lack of food.
The death brought the pod population down to just 77 whales. Fifteen years ago it was more than 100, and Dr. Lance Barrett-Lennard said that trend will likely continue unless people act.
“As a society, the first thing we have to do is decide how valuable these animals are; whether we really want them,” said Barrett-Lennard, a whale researcher for the Vancouver Aquarium.
“They’re an iconic species. They’re valuable to us culturally, I think, but it’s not my decision.”
Rhapsody’s death points to two ongoing problems researchers have been tracking: a shrinking food supply and problematic pollution.
Southern orcas only eat Chinook salmon, and Dr. Andrew Trites said the rivers Chinook need for spawning – including the Fraser, the Columbia and the Sacramento – are being ruined.
“In California, many of those rivers’ water has been diverted to grow strawberries. They no longer support healthy populations of salmon,” said Trites, director of the University of B.C.’s Marine Mammal Centre.
Rhapsody’s thin blubber layer and dryness of oil suggest she was malnourished for an extended time, and had been relying on body fat to survive.
Making matters worse were the industrial metals and other contaminants stored in that fatty layer, which are absorbed into orcas’ internal organs during times when food is scarce.
Aquarium researcher Dr. Peter Ross said those man-made poisons make whales more susceptible to disease and infertility, and can even put their fetuses at risk.
“What the female is doing when she is pregnant is transferring much of her load of these fat-soluble chemicals to her unwitting calf,” Ross said.
Of all killer whales on Earth, the southern population is considered the most toxic.
And there’s another form of pollution in the mix, according to researchers: noise. An abundance of ocean vessels in the waters off B.C. and the sounds they make interrupt the ability of orcas to find that increasingly scarce food.
Scientists believe with more digging, it could be possible to help the population survive – but it won’t be free.
“This is really a human values decision. Do we want to maintain these animals or not?” Barrett-Lennard said. “We’ve got to suck it up and face the reality that they may just die off right in front of our eyes. If you don’t believe that then nothing’s going to change.”
Watch CTV News at Six on Dec. 16 to learn more about how the killer whale population can be saved
With a report from CTV Vancouver’s Peter Grainger
