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Seeking a sea lion comeback

CMU grad student travels to Alaska to help solve depopulation mystery


​Growing up near the wild shores around Seattle, Washington, it was easy for Peter Han to become fascinated with sea lions.

Today, as a second-year conservation biology graduate student at Central Michigan University, he's working to save them — with help from a competitive grant that seldom goes to students outside the Pacific Northwest or Alaska.

Working in Alaska

Han spent the summer in Seward, Alaska, helping scientists at the Alaska SeaLife Center understand a massive die-off of Steller sea lions that began in the 1970s in Alaska's Aleutian Islands.

About 75 percent of the Stellers were wiped out in some areas, Han said.

In the family that includes all sea lions and fur seals, Stellers are the largest species, with males weighing as much as 2,600 pounds. They prey on fish and range throughout the northern Pacific Ocean coast.

Their deaths along the more southern coasts of Oregon, Washington and the Canadian province of British Columbia were easier to explain, Han said. They now are federally protected, but at the time the region's fishing industry received governmental permission to cull the animals. Some fishermen simply descended on the rookeries — where young are raised — and shot them.

Sea lion junk food?

In Alaska, there wasn't as much of that, Han said, and the problem remains a mystery. He said fewer sea lion pups were being born or surviving to adulthood.

A "junk food hypothesis" blames shifting currents at the time — and possibly overfishing today.

"Suddenly the fish that these guys were feeding on are not there anymore," Han said. "They're eating fish that are not fatty enough for them."

So perhaps even though they eat a lot, it's not enough to build up the fat stores the females need to carry their pregnancies to term or to sustain the pups once they're born.

Han and researcher John Maniscalco of the SeaLife Center want to know for sure.

"There are fewer pups, but we don't know why there are fewer pups," Han said. "There's been a slight rebound in some places but far from everywhere."

 

Life at the center

The center is close to a place where the sea lions congregate and breed during the summer. The scientists also observe the nearby rookery. During the spring, the researchers set up an elaborate remote-control camera system that relays video to the research center some 20 miles away.

The animals disperse during the winter, and smaller groups settle in isolated spots called haul-outs. At the haul-outs, the SeaLife center collected sea lion feces, or scat, to study population genetics. Han did the same at the rookery.

While also containing things such as shells and bits of prey, the freeze-dried and sifted scat can reveal the animal's DNA and possibly provide hints about its family line.

That's important because a mother and her offspring might have the same diet and suffer the same consequences — or enjoy the same benefits.

Still, no one knows what caused the Alaska die-off or the failure of the populations to rebound.

Back at CMU

Han started out with about 30 samples of scat and now has about 700. Most are at biology faculty member Brad Swanson's lab on the second floor of the new Biosciences Building. Han now is aided by undergraduate volunteer Carson Pakula.

"I'm trying to build this little network of who is related to whom and how related they are," Han said. "Are they inbred? How are they sorting the community out?

"We'll have a much better picture pretty soon, but those are some of the questions we're trying to address right now in the lab."

Grant supports the work

A graduate student research fellowship from the North Pacific Research Board helps Han and Swanson analyze DNA from all 700 scat samples.

Han landed the grant with the help of Swanson — his advisor — and Maniscalco.

"The grant is international and highly competitive, with acceptance rates usually below 15 percent," Han said. "We're also one of only a handful of institutions to win this award outside of the University of Alaska-Fairbanks, Oregon State University and the University of Washington.

This isn’t Han’s first research rodeo: As an undergrad in 2013 and 2014, he worked in Siberia with The Polaris Project, a National Science Foundation-funded Woods Hole Research Center program that gives undergraduate students arctic research experience. Han worked mainly on how carbon enters the atmosphere from thawing soil and how grazing and browsing animals such as horses, musk oxen and moose can sequester more carbon from the arctic environment.

Winning the NPRB grant also means Han will present his research at the Alaska Marine Science Symposium in Anchorage, Alaska, after completing his master's degree in 2019.

Han's research also has the support of a grant in aid of research from Sigma Xi scientific research honor society, and CMU's own Student Research & Creative Endeavors grant.


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