The Seasonal Diet, Distribution, and Counts of Harbor Seals (Phoca vitulina vitulina) and Gray Seals (Halichoerus grypus atlantica) in Pleasant Bay and Chatham Harbor, Cape Cod, Massachusetts

Lisa Sette^1,*, Corey M. Accardo¹, Katherine McKenna², Kristen Patchett², Kathryn Rose², Brian W. Sharp², and Gordon T. Waring³

¹Center for Coastal Studies, 5 Holway Avenue, Provincetown, MA 02657. ²Marine Mammal Rescue and Research, International Fund for Animal Welfare, Yarmouthport, MA, 02675. ³Capeseal, PO Box 215, Woods Hole, MA, 02543, MA. *Corresponding author.

Northeastern Naturalist, Volume 27, Special Issue 10 (2020): 98–113

Abstract
Due to seal bounties throughout New England in the 19th and 20th centuries, Phoca vitulina vitulina (Harbor Seal) and Halichoerus grypus atlantica (Gray Seal) were nearly extirpated from the east coast of the US. The 2 species are now recovering and are repopulating southern New England haul-outs. To begin to develop an understanding of their current distribution and aspects of their diet inside Pleasant Bay and Chatham Harbor, we conducted monthly aerial surveys in 2014 and 2015 and collected scat monthly from January 2016 through March 2017. Although both species were observed to be hauling out, little temporal overlap of Harbor and Gray Seals was detected. While a variety of prey species were detected in the scat samples analyzed, Ammodytes spp. (sand lance) occurred most frequently in the diet of both seal species.

Download Full-text pdf (Accessible only to subscribers. To subscribe click here.)