FIN WHALE (Balaenoptera physalus): Western North Atlantic Stock

• Main Authors: Stock Definition, Geographic Range
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1997
• Subjects: Balaenoptera physalus; Fin whale; Newfoundland; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.294.9097; http://www.nmfs.noaa.gov/pr/pdfs/sars/ao1997whfn-wn.pdf

The Scientific Committee of the International Whaling Commission (IWC) has proposed stock boundaries for North Atlantic fin whales. Fin whales off the eastern U.S., north to Nova Scotia and on to the southeast coast of Newfoundland are believed to constitute a single stock under the present IWC scheme (Donovan 1991). However, the stock identity of North Atlantic fin whales has received relatively little attention, and whether the current stock boundaries define biologically isolated units is uncertain. The existence of a subpopulation structure was suggested by local depletions that resulted from commercial over harvesting (Mizroch et al. 1984). Confirmation or revision of existing proposed stock boundaries awaits input from techniques such as molecular genetics or telemetry. Fin whales are common in waters of the U.S. Atlantic Exclusive Economic Zone (EEZ), principally from Cape Hatteras northward (Figure. 1). Fin whales accounted for 46% of the large whales and 24 % of all cetaceans sighted over the continental shelf during aerial surveys (CeTAP 1982) between Cape Hatteras and Nova Scotia during 1978-82. While a great deal remains unknown, the magnitude of the ecological role of the fin whale is impressive. In this region fin whales are the dominant cetacean species in all seasons, with the largest standing stock, the largest food requirements, and therefore the largest impact on the ecosystem of any cetacean species (Hain et al. 1992). There is little doubt that New England waters Figure 1. Distribution of fin whale sightings from NEFSC shipboard and aerial surveys during the summer in 1990-1995. Isobaths are at 100 m and 1,000 m. constitute a major feeding ground for the fin whale. There is evidence of site fidelity by females, and perhaps some substock separation on the feeding range (Agler et al. 1993). Seipt et al. (1990) reported that 49 % of identified fin whales on Massachusetts Bay area feeding grounds were resighted within years, and 45 % were sighted between years. While recognizing localized as ...