Our Baby Orcas Are Mostly Boys. That Has Scientists Freaked Out | KUOW News and Information

Our Baby Orcas Are Mostly Boys. That Has Scientists Freaked Out

Apr 1, 2016

Scientists were ecstatic. After years of worrying about the killer whale population in Puget Sound, eight baby orcas were born and thriving.

Then came photos of their bellies. Most of the babies are boys, they realized.

At least five – but probably six – of the new orcas are male. One remains a mystery. And just one is a girl. They call her Scarlet and say she’s spunky and growing like a weed.

But if she’s the only female, that means she’s the only whale in this age group that could conceive.

Given that female orcas start having babies around age 10 – and have babies every three years at best – that signals slow population growth.

“We need some females out there,” said Michael Harris, executive director of Pacific Whale Watch Association.

So why so many boys? That hasn’t been fully explored, but there are at least two possibilities.

One theory is toxic pollution.

“PCBs, flame retardants, mercury – junk people put in the oceans – some people have speculated that this might have some determining factor in having so many males born in this last year,” Harris said.

The orca known as L91 and her new calf, L122, are seen in a photo taken from a drone by NOAA Fisheries Southwest Fisheries Science Center and Vancouver Aquarium for health assessment. The drone was more than 100 feet from the orcas.
Credit NOAA Fisheries Southwest Fisheries Science Center and Vancouver Aquarium

That ocean junk gets into the orcas’ blubber, said Deborah Giles, research director for the Center of Whale Research. Toxins stay there, untapped, if the whales are well fed. But if they don’t eat enough – and they eat about 150 pounds of salmon a day – their bodies start to draw on their blubber.

“It’s constant feast or famine for the killer whales,” Giles said. “Every time they stop eating enough food, they start circulating those toxins.”

Research shows that other mammals tend to birth boys after a period of starvation. More human boys are born after war, for example. Giles wonders if the same phenomenon applies to these orcas.

Most of the babies born belong to J-Pod, which spend most of their time in Puget Sound. J-Pod is part of a larger group of local killer whales known as southern residents.

Scientists believe that J-Pod was so fertile in 2013 because its members hung out on the outer coast eating Columbia River Chinook salmon. It was a heartier run than usual, which put the females in fighting shape to get pregnant.

Scarlet was the first born, on Dec. 30, 2014. Within 14 months, the local killer whale population grew to 84 killer whales. Scientists rejoiced, because it meant that this population, previously deemed endangered, was growing again.

L122, one of the newest members of the Southern Resident Community of orcas, spotted Sept. 7 near Sooke, British Columbia.
Credit Dave Ellifrit, Center for Whale Research

But fisheries experts predict dismal salmon runs ahead. Giles said that means we could see orca deaths in years to come, especially now that there are more mouths to feed.

Giles wishes that these local pods were more like the transient whales that travel down the West Coast. Those travelers have a more varied palate. They eat porpoises, harbor seals and sea lions, among other sea mammals, and they’re doing well as a result.

“How about you take a page out of your cousin’s playbook and eat a porpoise?” Giles said.

But those transient whales have little in common with these three pods. They may look alike, but mitochondrial DNA shows their last mating with the Puget Sound orcas’ ancestors was 700,000 years ago. They may as well be a different species, Giles said.

(The local orcas enjoy playing with those porpoises, often to death, but it never occurs to them to take a nibble.)

Giles hopes the National Oceanic and Atmospheric Administration focuses intensely on reviving salmon population in the ocean, because the southern resident orcas are so tied to their prey.

She said NOAA spends a lot of time examining vessel noise, but that food and toxins need to be examined further.

L123 is seen in Haro Strait. Capt. Mark Malleson of Prince of Whales Whale Watching took the photo for the Center for Whale Research.
Credit Courtesy Mark Malleson/Pacific Whale Watch Association

The transient whales are doing fine despite the noisy containerships, she said. “The only difference is that the transients have enough food, and the residents don’t.”

Despite the bleak outlook, Harris with Pacific Northwest Whale Watch hopes that baby births are celebrated.

“You can never look at a baby boom and not have a big smile on your face,” he said.