Figure 1. Individual humpback whale sightings, 24 April-10 May 2010.
Figure 2. Satellite telemetry from two of the tagged humpback whales. The tag shown in white stopped transmitting on 8 May 2010, but the tag shown in black was still giving reliable positions as of this writing.
Figures 3 a, b. Humpback whales photographed off St. Francois, Guadeloupe.
Humpback whales migrate to the West Indies to breed each winter from a broad range of feeding grounds across the temperate and high latitudes of the North Atlantic Ocean.
The largest concentrations of North Atlantic humpbacks today occur on Silver, Navidad, and Mouchoir Banks to the north of Hispaniola, as well as in Samaná Bay in the northeastern Dominican Republic.
Since scientific research on humpbacks in the Caribbean began in the early 1970s, researchers have worked in this area to establish abundance estimates and describe the spatial and temporal distribution, habitat preference, migration, mating behavior, acoustics, stock identity, and genetics for the entire North Atlantic population.
Although humpback whales have historically used the entire Caribbean Sea as a winter breeding ground, a comparison of modern sighting data to whaling records indicates a shift in distribution from the Lesser (southern) to the Greater (northern) Antilles.
While humpback whales over-wintering in the Dominican Republic are one of the most intensely studied large whale populations in the world, very little survey effort has taken place in Guadeloupe or elsewhere along the Antillean chain. On 24 April 2010, I met with researchers from the Dominican Republic, University of Guadeloupe, and University of Paris South in Guadeloupe to conduct a humpback whale tagging project.
This survey was meant as the first step in an attempt to answer some of the following questions: What feeding ground stock do these whales come from? What sex and maturity classes are represented at this time of year? How long are whales staying in Guadeloupe waters?
Eighteen individual whales, including four calves, were observed during 9 days of survey effort (Fig. 1). Seventeen of those individuals were biopsied, and five adults were satellite-tagged (using an air rocket transmit deployment system and tags designed and manufactured by Wildlife Computers in Redmond, Washington). To date, locations have been received from three tags (Fig. 2).
One tag was still transmitting positions as of this writing, as the whale continued her northward migration with her calf. High quality song recordings were obtained from three individuals.
The College of the Atlantic and the Provincetown Center for Coastal Studies curate local and international North Atlantic Humpback whale catalogues (NAHWC) that include photographs and sighting history data for humpbacks seen during the feeding and breeding seasons.
To date, none of the individuals photographed during the Guadeloupe survey (Figs. 3a, b) have been matched to the smaller Gulf of Maine humpback whale catalog, but comparisons with the NAHWC are under way.
The biopsy samples are being processed at the University of Guadeloupe, and we hope they will shed some light on the stock structure and feeding ground origin of the animals seen in this area. Further acoustic, satellite-telemetry, genetic, and photo-identification studies are needed to help determine the spatio-temporal distribution of the humpbacks that use the Leeward Islands during the winter months.
