Steller Sea Lion To Give Birth to New Pup

Alaska’s Western stock of Steller sea lions is critically endangered. The Alaska SeaLife Center’s Lori Polasek is trying to figure out why. She and her colleagues hope that breeding sea lions in captivity will help them better understand those in the wild. Although recent sea lion pregnancies at the SeaLife Center haven’t been successful, scientists say the latest one could go exactly as planned.

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sitka sea lion
Sitka is one of the female Steller sea lions at the Alaska SeaLife Center. Photo by Sara Bernard, APRN-Anchorage.

Marine mammal scientist Lori Polasek says the research they’re doing here is pretty unique. “It’s the only breeding program in the world where we’re collecting data that hopefully will be turned around and help the population,” Polasek says.

Scientists aren’t sure why the Steller sea lion population dropped so quickly — it could be competition with fisheries, for instance, or killer whale predation. But studying how they produce successful young could be one key to building their population back up.

Right now, the SeaLife Center has two males – one large breeder, Woody, and one younger male, Pilot, who Polasek says will fill Woody’s shoes eventually.

“Pilot at three was already bigger than Woody at five,” she says. “And just wait until you see Woody. He’s an impressive sea lion.”

Woody is almost 2500 pounds. And he recently put on an extra 500 just because he shared a wall with Pilot, the younger male, and probably wanted to show him who was boss.

“As you can tell, it’s very guttural… very deep,” says Polasek as Woody lets out a bellow. “You can smell a bit of his musk coming through… Whoo! It’s almost asphyxiating, it’s so thick.”

woody sea lion
Woody is the largest male sea lion at the SeaLife Center. Photo by Sara Bernard, APRN-Anchorage.

There are four female sea lions at the SeaLife Center, and one, named Eden, is about to give birth. Polasek says Eden’s not the most attractive sea lion – she’s a bit hard of hearing, so often cocks her head to one side, and always has a tongue sticking out. “But she is the apple of Woody’s eye. When she is on exhibit, she is his primary focus. He will breed with the other animals, but he always goes back to Eden.”

Eden is also a favorite of the trainers and researchers who work with her – in part because she exhibits some unusual behaviors, such as protecting other females when Woody gets too aggressive. There’s no evolutionary reason for this.

“For her to make that move to put herself in between the two of them has really sort of endeared her to everyone else,” Polasek says. “Here she is protecting this other sea lion. So she is really, I would say, just a special, special sea lion.”

And now that Eden is pregnant – very pregnant  – a handful of scientists, vets, and trainers are gathering for an ultrasound.  Senior veterinarian Pam Tuomi  pulls out her portable ultrasound machine, about the size of a large laptop.

Eden comes out of her private pool to lie down comfortably in what the trainers call a “chute,” a sort of metal crate without walls. While Tuomi crouches nearby with the ultrasound wand, another trainer feeds her fish.

“Okay! 120. Good normal heart rate,” Tuomi says. “This kid is big enough I can’t get a cross section of the ribs anymore.  But I think I can at least freeze the heart picture for a minute here.”

Eden’s still eating, the ultrasound looks good, and all is as it should be. Tuomi says even though it isn’t completely necessary, they’ve been doing ultrasounds every day.

“We’ve been trying to do it daily, as long as she has the patience for it, just to make us feel better. It doesn’t make any difference to her. But it’s nice for the staff to know every day that the pup still looks fine.”

sitka sea lion
Sitka is not yet receptive to Woody’s advances. Photo by Sara Bernard, APRN-Anchorage.

The fact that this pregnancy is going well is a big deal. The past two haven’t –  the first pregnant female,  Kiska, died from pancreatic cancer very late in her pregnancy. The pup died too.

“It was really devastating,” says Polasek. “To lose an animal that we we’re watching. My kids have been watching on the computer at home. My daughter for weeks afterwards said, ‘Where’s the baby, Mama?’ It just was heartbreaking.”

The second, Tasu, gave birth to a stillborn fetus last month. And so far, Polasek says that none of the scientists involved can figure out why. “It was full grown, really mature, looked great, looked in good condition, and we don’t know yet.”

While it’s difficult to lose an animal that they’ve been counting on, Polasek looks on the bright side. “Tasu, after the stillborn was past, she went back out with Woody and has bred again, so a very natural progression afterwards.”

But for now, the focus is on Eden. When asked if she could give birth any day now, researchers say it could happen any hour.

Research described is authorized under National Marine Fisheries Service Permit No. 14334.