Harbor seal (Phoca vitulina) populations have experienced significant declines over the past 50 years, which might be related to climate-driven changes to habitat. Approximately 10-15% of harbor seals in Alaska use tidewater glacial ice as substrate for pupping, molting, and resting, but these habitats are disappearing due to warming temperatures. Little is known about the fine-scale characteristics of glacial habitats used by these animals, making it difficult to identify and quantify habitat changes over temporal and spatial scales. This study evaluates the accuracy of using land, water, and air platforms to measure fine-scale dimensional characteristics of glacial ice habitats and investigates the practicality of using a geographic information system (GIS) modelling technique to quantify landscape features of glacially influenced nearshore environments. Measurements of icebergs were obtained from images captured from land, water, and air platforms, and statistically compared with the true heights of the selected icebergs. Preliminary results indicate that there were no statistical differences between the true heights of icebergs and heights extracted from images that were captured from land and water platforms. Height measurements calculated from the air platform using an unmanned aerial vehicle (UAV) were significantly over-estimated by a constant amount, but correctable. Aerial images of nearshore regions around tidewater glaciers in Alaska were imported into a GIS program and a model developed by a NOAA collaborator was successfully used to identify and separate floating icebergs from water and land features. Data from this effort will be used to better understand how harbor seals utilize these changing ecosystems. Predicting how marine mammal populations respond to habitat changes will be essential for developing conservation management strategies in the 21st century.
