Harbor seal migrations in the spotlight at Friday Fireside Lecture

Marine biologist to talk on movement of Glacier Bay seals

To a seal, Glacier Bay National Park is likely a fitting spot to make a home — the pristine and guarded environment is lucrative in both food and protection.


But once the post-breeding season, which runs from September to April, begins many “resident” harbor seals hit the road, so to speak and range into northern portions of Southeast Alaska and along the continental shelf region of the eastern Gulf of Alaska. They have been tracked from Sitka to Prince William Sound, according to the National Park Service.

This information is relatively new to researchers like Jamie Womble, who works as a marine biologist with the NPS at the Glacier Bay Field Station in Juneau. Womble, who leads the harbor seal research and population monitoring in Glacier Bay National Park, and her team have been studying the winter migration patterns for Glacier Bay harbor seals since 2007.

She said the project kicked off after a steep decline in seal populations was identified in the national park. 

According to a graphic released by the NPS, more than 4,000 seals were counted in Johns Hopkins Inlet in August of 1992. Sixteen years later, barely more than 1,000 seals were counted in the same area and within the same time frame. 

"Seals in Glacier Bay had experienced precipitous declines," Womble said. "So one question that was unresolved was, 'where animals were spending their time?' We know where they are in the summer, but in the winter (we wanted to know) 'were they sticking around or leaving?'"

Womble said it all comes down to cause and effect. 

"When you have a species that has serious declines, you begin to wonder what is causing those declines," she said.

To conduct her research Womble and her team captured juvenile and adult female harbor seals in Johns Hopkins Inlet, in the upper West Arm of Glacier Bay in September of 2007 and 2008. Carefully, Womble and her team glued small, temporary satellite-linked transmitters to the heads of captured animals.

As the data was examined, the team found that while some seals stayed within the confines of the bay, others traveled into areas of Southcentral Alaska. Three seals for instance, one juvenile and two adult females, tallied a cumulative traveling distance during the post-breeding season that exceeded 3,000 kilometers, according to the NPS.

Womble will talk on her research findings tonight as part of the U.S. Forest Service-sponsored Fireside Lecture series beginning at 6:30 p.m. and again at 8 p.m. at the Mendenhall Glacier Visitor Center.

The event is free and open to the public.


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