US Navy


Marine Species Monitoring

Seal Tagging and Tracking in Virginia

Introduction & Objectives

The lower Chesapeake Bay and the Virginia nearshore waters represent one of the busiest hubs of naval activity on the east coast and hosts numerous pierside facilities, bases, vessels, shipyards, and in-water training ranges. Seals seasonally inhabiting and transiting through these areas could be impacted by military activities including vessel traffic of all sizes, dredging, pile driving and other activities.  Understanding occurrence and habitat use behaviors of these animals in the vicinity of these activities is critical to mitigating potentially harmful interactions and obtaining appropriate permits for these actions. The information gathered from this effort will provide valuable baseline data needed for the future assessment of seal movement and site fidelity along the Mid-Atlantic coast and especially for in-water training associated with Joint Expeditionary Base (JEB) Little Creek-Fort Story, and Naval Station Norfolk and Naval Air Station Oceana - Dam Neck Annex.

Navy biologists have been researching seal occurrence in the region since 2013 and conducting systematic haul-out counts in the region since 2014. The information and data collected to date indicate that seals are probably utilizing the area to a much greater degree than previously thought, and that there is a regular seasonal occurrence of seals in the region between fall and spring.  However, our understanding of seal occurrence within this region is still extremely limited, meriting further monitoring to ensure compliance with a suite of environmental laws (e.g. Marine Mammal Protection Act). From haul-out counts, citizen reports and stranding records, the seal species that could be included in this effort are: harbor seals (the predominant species), grey seals and on rare occasions, harp seals.

While there is an improved understanding of the seasonality of seals to the region from haul-out counts, information on the movements of individuals within this region are non-existent. These data are critical in assessing the potential for impacts to seals during U.S. Navy training operations and in high-vessel traffic areas in the Chesapeake Bay and Virginia coastal waters.

This proof-of-concept study is being undertaken to establish the feasibility of using satellite tags during the fall/winter to understand seal movement in the area, to determine when seals migrate in and out of the region, and where they migrate to in the spring and summer. Increased knowledge of the movements, habitat utilization, and seasonality of seals found in the Chesapeake Bay and Virginia coastal waters will allow the Navy to limit interactions with these protected species, design better mitigation measures where interactions are unavoidable and obtain the appropriate authorizations to maintain environmental compliance.

Technical Approach

This proof-of-concept tagging project will focus on capturing, tagging, and releasing healthy harbor seals (adults if possible) in the lower Chesapeake Bay and nearby Atlantic Ocean beaches from November 2016 to April 2017. The team will attempt to deploy four SPOT6-311A tags and one SPLASH10-309A tag. The SPOT6 tag is a location-only tag that reports horizontal movement of the animal(s), and also has wet-dry sensor indicating when the animal’s head is above water and data can be transmitted to satellites. The SPLASH10-309A reports both horizontal movement (location) and vertical movement (depth), and also has a wet-dry sensor for purposes of data transmission. Tags will be programmed to a duty cycle to allow for delineation of previously unknown haul-out locations.

Permitted researchers will attach satellite positioning tags to seals externally using methods and techniques consistent with similar projects conducted on these species, and in accordance with all stipulations of NMFS permit # 17670. The tagging team will also collect a suite of life history and other research samples in accordance with permit stipulations, which may include scat, blood, blubber (via biopsy), vibrissae, and fur.

Tag return data will be used to conduct a home range analysis, and to create maps of the seals’ transits and haul-out locations. Haul-out behavior in %-dry time and, if possible, temperature preferences of tagged seals will also be reported.

Progress & Results

Tagging field work is planned for the winter of 2016-2017.  Check back for updates.