North Atlantic humpback whales (Megaptera novaeangliae) of the West Indies distinct population segment (Bettridge et al. 2015) migrate from six northern feeding grounds to Caribbean Sea waters during the winter months (Waring et al. 2013). Some whales do not take part in this migration and use the Mid-Atlantic region to over-winter (Barco et al. 2002). Understanding the occurrence and behavior of humpback whales in the vicinity of U.S. Navy training and vessel transiting activities off the coast of Virginia is important in mitigating potentially harmful impacts on the species.
Humpback whale sighting information off the Virginia Beach area has been collected with various methods and sporadic field effort, with shore-based counts in 1991 and vessel-based photo-identification efforts in 1992 (Swingle et al. 1993), and further cataloging efforts using photos taken on whale-watching excursions and from stranded whales (Barco et al. 2002). Data have shown some individuals returning in subsequent years, and it is suggested that the area may act as a supplemental winter feeding grounds for the returning whales (Barco et al. 2002). Photos of whales sighted off Virginia were matched to cataloged whales from the Gulf of Maine, Newfoundland, and the Gulf of St. Lawrence regions (Barco et al. 2002). Information on the movements of individuals within this region are very limited, and these data are important to assess the potential for disturbance to humpback whales found the U.S. Navy training operations and high-traffic areas in the Chesapeake Bay and coastal waters.
The objectives of this project under the Navy’s Marine Species Monitoring Program are to establish baseline occurrence and behavior data for humpback whales in the Hampton Roads mid-Atlantic region by addressing the following questions:
• What age classes (juveniles, sub-adults, adults) are utilizing the waters within and adjacent to the mouth of the Chesapeake Bay?
• Do humpback whales exhibit site-fidelity over periods of days to years?
• Do humpback whales congregate in specific high-traffic and/or high-use Navy training areas?
• Do humpback whales spend significant time within or move through areas of U.S. Navy live-fire and mine neutralization exercise (MINEX) training)?
This project focuses on nearshore non-systematic visual surveys from a small vessel with associated photo identification, unmanned aerial systems, biopsy sampling, and tagging using Wildlife Computers Smart Position and Temperature (SPOT6) Argos-linked satellite tags as well as SPLASH-F variations that record diving behavior and integrate Fastloc© GPS (Wildtrack Telemetrry Systems Limited) in the Low Impact Minimally Percutaneous Electronic Transmitter (LIMPET) configuration. These small tags measuring only two inches in length and height and less than an inch wide, attach to the dorsal fin or base of the dorsal fin by two sterilized darts. This placement allows frequent transmissions to the Argos satellites when the animals surface, providing locations throughout the day on the whereabouts of the tagged individuals. Tags are designed to eventually fall off the animal after a period of weeks. . Primary objectives of this project include:
1. Collect baseline occurrence data (location, sex, group size, behavior) of humpback whales (and other species of baleen whales opportunistically)
2. Obtain identification photographs and drone video footage of humpback whales for inclusion in regional and local catalogs, as well as morphometric measurements and health assessments
3. Collect biopsy samples of humpback whales for sex determination, mitochondrial control region sequencing, and microsatellite genotyping of tissue samples, and stable isotope analysis to determine foraging related to prey consumption.
4. Conduct satellite tagging to document seasonal humpback whale movement patterns in the nearshore waters off Virginia Beach, specifically whether the whales spend significant time in areas of high shipping traffic and/or areas of U.S. Navy training exercises.
The study area includes waters in and around the mouth of the Chesapeake Bay as well as the W-50 MINEX region off Virginia Beach. Although the operating area for each survey is chosen depending on weather conditions and reports of humpback whales or other baleen whales in the area, there will always remain a focus on areas of high Navy use, such as the W-50a MINEX zone and shipping channels. During each encounter, every effort will be made to collect identification photographs of the dorsal fins and tail flukes (when possible). Based on the animal’s identification, satellite tags may be deployed and biopsy samples may be collected, depending on what data has previously been collected from that individual.
Researchers from HDR and the U.S. Navy have conducted 130 nearshore surveys between January 2015 and March 2020 totaling 834 hours of effort and covering 13,315 km of trackline. During these surveys, there have been 471 baleen whale sightings, including 445 sightings of humpback whales totaling 161 unique individuals, 18 sightings of fin whales (Balaenoptera physalus) totaling 17 unique individuals, 12 sightings of minke whales (Balaenoptera acutorostrata) totaling 11 unique individuals, and one sighting of an unidentified large whale. Sixty-two (62) biopsy samples have been collected and 60 satellite tags deployed (46 SPOT6 and 14 SPLASH-F) through the 2019/20 field season.
As of March 2020, there have been 182 unique humpback whales photo-identified during the course of this project. Thirty-one (31) individuals were identified during the first year of effort (2014/2015), 38 were identified during the second year of effort (2015/2016) (including six re-sights from the previous year), 60 were identified during the third year of effort (2016/2017) (including 17 re-sightings from the previous two years), 27 were identified during the fourth year of effort (2017/2018) (including 8 re-sightings from the previous three years), 38 were identified during the fifth year of effort (2018/19) (including 5 resightings from previous years), and 28 were identified during the the most reecent 2019/20 season (including 4 resights). Approximately three-quarters of individuals were estimated to be juveniles based on size assessment in the field. Photo-IDs are incorporated into the Mid-Atlantic Humpback Whale Catalog and also shared with other regional catalogs. Although matching for these images is ongoing, matches to known animals from the Gulf of Maine. Newfoundland, and St. Pierre and Miquelon have been made.
Tagging results show that the area near the mouth of the Chesapeake Bay is heavily utilized by humpbacks whales. Using data collected from the first three years of satellite tagging effort, Aschettino et al. (2020) found thatindividuals spend considerable time engaged in foraging behavior at or near the mouth of the Chesapeake Bay. These results indicate that local habitat preferences directly overlap with high-traffic areas, which can have deadly consequences.
During the 2015/2106 field season, four whales were encountered with fresh injuries, likely from vessel strikes. During the 2016/2017 field season three whales died of vessel-related injuries over an 8-day period. In April 2017 the National Marine Fisheries Service declared an Unusual Mortality Event (UME) for humpback whales between Maine and Florida, demonstrating the need for continued research on animals in this region.
The 2020/2021 field season will be commencing in the fall of 2020 and focus primarily on a collaboration with Duke University to assess reactions of juvenile humpbacks to approaching ships and continued nearshore photo identification work.
Blog Posts, Presentations, and Publications
Location: Nearshore Mid-Atlantic
Funding: FY14 - $320k, FY15 - $260k, FY16 - $370k, FY17 - $325k, FY19 - $248k, FY20 - $257k
Joel T. Bell
Environmental Conservation, Marine Resources Section