GIS-based analysis of ice-breeding seal strandings in the Gulf of Maine

David E. Harris, University of Southern Maine
Sat Gupta, University of Southern Maine

Copyright of Northeastern Naturalist is the property of Eagle Hill Institute

Originally published in Northeastern Naturalist 2011


Phoca groenlandica (harp seals) and Cystophora cristata (hooded seals), two species of ice-breeding seals, are being sighted more frequently onshore in the Gulf of Maine since 1990, but little is known about their behavior in this ecosystem. We obtained records of 904 ice-breeding seal stranding locations in the Gulf of Maine between 1996 and 2002 from NOAA Fisheries and used a geographic information system (GIS) to conduct group-wise comparisons by species (using non-parametric techniques), and to determine the predictors of high seal-stranding density (using ordinal logistic regression analysis). Compared to harp seals, hooded seals stranded closer to deep water, farther north, and near different intertidal shoreline types, Predictors of high seal-stranding density included being closer to an offshore basin, deep water, public land, and areas of lower human population. These results may reflect seal behavior and reporting bias