Investigating the Fragmentation of Pacific Walrus Sea-Ice Habitat in the Wainwright and Saint Lawrence Island Regions of Alaska using Landsat Satellite Data

Authors: Anthony Himmelberger*, Clark University, Karen Frey, Clark University, Associate professor, Florencia Sangermano, Clark University, Assistant Professor
Topics: Cryosphere, Remote Sensing, Polar Regions
Keywords: sea ice, pacific walrus, fragmentation, shoal, landsat, remote sensing, ice pack
Session Type: Guided Poster
Day: 4/4/2019
Start / End Time: 1:10 PM / 2:50 PM
Room: Roosevelt 3.5, Marriott, Exhibition Level
Presentation File: No File Uploaded

Sea ice in the Arctic has been declining rapidly over the course of the past several decades. The Pacific Walrus relies on the ice pack and floes around the Saint Lawrence Island (SLI) and Wainwright regions of Alaska as means of rest and platform for feeding, in particular when the ice floes are over extremely biologically productive shoals, such as the Hannah Shoal northwest of Alaska. Lower sea ice concentrations lead to earlier fragmentation of ice pack and shorter annual persistence. This greatly affects the livelihood of the Pacific Walrus, as they are forced to travel farther to reach feeding areas, sometimes being forced to rest on land. This study focuses on 24 images ranging from 2008 to 2018, chosen because they represent a wide array of sea ice conditions through the ten year time scale. From 2008 to 2012, ice pack was generally stable around SLI with sea ice concentrations usually 100% until mid-May and annual persistence ranging from ~135-175 days, whereas from 2013 to 2018 sea ice concentrations went from 100% in May of 2013 to only reaching 70% for two weeks in March 2018 and an annual persistence of ~160 days in 2013 to ~30 days in 2018. Remote sensing techniques were used using TerrSet to classify sea ice as thick or thin ice and FRAGSTATS was used to assess fragmentation. This study contributes to a larger foundation of knowledge about sea ice decline, habitat fragmentation, and the overall effects on the Pacific Walrus population.

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