Patterns of Seal Strandings and Human Interactions in Cape Cod, Massachuettes

Abstract

From 1999 to 2004, 622 pinniped strandings were recorded by the Cape Cod Stranding Network (CCSN). Fifty-seven of these strandings were classified as human interaction cases. Strandings were defined as human interaction (HI) cases if there was evidence of anthropogenic injury or harassment present of noted upon necropsy. To minimize the frequency and severity of adverse interactions between seals and humans, it is important to first understand the spatial and temporal patterns of such interactions. Using stranding data obtained from the CCSN, I examined the seasonal and spatial distribution of interactions between humans and four pinniped species: harp seals (Phoca groenlandica), harbor seals (Phoca vitulina), gray seals (Halichoerus grypus), and hooded seals (Cystophora cristata). The majority of the HI cases were fishery entanglements (29 seals), followed by boat collisions (11 seals), harassment (9 seals) and blunt trauma (8 seals). I compared the frequency of all strandings with the length of shoreline in each of the Cape’s fifteen towns. I then considered the frequency of strandings in relation to the number of beach vehicle permits sold in each town for the summer season. The highest number of HI strandings occurred in the summer months in the Chatham area. Knowledge of seasonal and spatial patterns of HI cases will allow managers to focus mitigation efforts in times and areas when such interactions occur frequently. This knowledge will also allow managers to better disseminate information on appropriate means of viewing wild seals.