Year Round Seal Population Surveys

Aerial Seal Surveys - Monthly Surveys of Seals in Southeastern Massachusetts


As seal populations have increased in New England waters, managers have confronted a proliferation of issues related to tourism, fisheries management, water quality, and the increasing occurrence of white sharks in the vicinity of seal haul out locations, particularly along the outer beaches of Cape Cod. An assessment of the status of the population of seals in the region is an essential component of the management of the variety of human uses of the coastal ecosystem where seals are increasingly common. Many of the issues that surround the increasing seal population, while well defined, lack the input of hard scientific information that will allow managers to understand and forecast the impact of seal populations on the coastal ecosystem. This project is intended to provide the critically important population status and trajectory information that will allow managers to plan for future management actions.


The goal of this project is to conduct year-around monthly aerial surveys of major seal haul-out sites in southeastern Massachusetts coastal waters to increase the time series on seal abundance and habitat use.

Need for Project

Unlike harbor seals, gray seals have established a year-around population in southern New England, particularly in Cape Cod and Nantucket Sound waters.   Expanding the monthly aerial surveys to include the late spring and summer months will provide the first comprehensive aerial survey of the summer population and  address a critical gap in our understanding of the summer gray seal population.


Aerial surveys are being conducted in a Cessna Skymaster (models 336 or 337; N2697S), a twin-engine high wing aircraft. The Center for Coastal Studies (CCS) Aerial Survey Program complies with the National Marine Fisheries Service (NMFS) Northeast Regional Office Commercial Aviation Services Requirements and safety and operations procedures. Track line data is recorded in Logger 2000 and entered in a format compatible with the CCS and Northeast Fisheries Science Center (NEFSC) database.

The Northeast Fisheries Science Center (NEFSC) and other regional seal research organizations are collaborating on analysis of the combined regional data sets to determine long-term trends in harbor and gray seal abundance and habitat use in southeastern Massachusetts, particularly in the Cape Cod-Nantucket Sound region.

Last updated: December 22, 2014