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HUMPBACK WHALE (Megaptera novaeangliae): Western North Atlantic Stock
| Content Provider | Semantic Scholar |
|---|---|
| Copyright Year | 1997 |
| Abstract | STOCK DEFINITION AND GEOGRAPHIC RANGE During summer there are at least five geographically distinct humpback whale feeding aggregations occurring between latitudes 42°N and 78°N. These feeding areas are (with approximate number of humpback whales in parentheses): Gulf of Maine (400); Gulf of St. Lawrence (200); Newfoundland and Labrador (2,500); western Greenland (350); and the Iceland-Denmark strait (up to 2,000) (Katona and Beard 1990). The western North Atlantic stock is considered to be include all humpback whales from these five feeding areas. Humpback whales from all of the western North Atlantic feeding areas migrate to the Caribbean in winter, where courtship, breeding, and calving occur. The majority (85%) are found on Silver and Navidad Banks off the north coast of the Dominican Republic. The remainder are scattered in Samana Bay (Dominican Republic), along the northwest coast of Puerto Rico, through the Virgin Islands, and along the eastern Antilles chain south to Venezuela (Katona and Beard 1990). Courtship groups on the wintering ground contain whales from different feeding aggregations, so that humpbacks from the western North Atlantic probably interbreed (Katona et al. 1994). Apparently, not all humpback whales from this stock winter in the West Indies, as there are winter reports from Bermuda, the Gulf of Maine, Newfoundland, Greenland, and Norway (Katona et al. 1994) Clapham et al. (1993) reported a high degree of individual site fidelity, both within and between years, from a longterm study of identified humpback whales in waters off Cape Cod. Some reproductive parameters which have been estimated for humpback whales from this area are discussed below. An increased number of sightings of young humpback whales in the vicinity of the Chesapeake and Delaware bays occurred in 1992 (Swingle et al. 1993). Wiley et al. (1995) reported 38 humpback whale strandings which occurred during 1985-1992 in the U.S. mid-Atlantic and southeastern states. Humpback whale strandings increased, particularly along the Virginia and North Carolina coasts, and most stranded animals were sexually immature. They concluded that these areas are becoming an increasingly important habitat for juvenile humpback whales and that anthropogenic factors may negatively impact whales in this area. There have also been a number of wintertime humpback sightings in coastal waters of the southeastern U.S. (NMFS unpublished data; New England Aquarium unpublished data; Florida DEP, unpublished data). Whether the increased sightings represent a distributional change, or are simply due to an increase in sighting effort, is presently unknown. Feeding is the principal activity of humpback whales in New England waters, and their distribution in New England waters has been largely correlated to prey species and abundance, although behavior and bottom topography are factors in foraging strategy (Payne et al. 1986, 1990). Humpback whales are believed to be largely piscivorus when in these waters, feeding on herring (Clupea harengus), sand lance (Ammodytes dubius), and other small fishes. Commercial depletion of herring and mackerel led to an increase in sand lance in the southwestern Gulf of Maine in the mid 1970s with a concurrent decrease in humpback whale abundance in the northern Gulf of Maine. Humpback whales were densest over the sandy shoals in the southwestern Gulf of Maine favored by the sand lance during much of the late 1970s and early 1980s, and humpback distribution appeared to have shifted to this area (Payne et al. 1986). An apparent reversal began in the mid 1980s, and herring and mackerel increased as sand lance again decreased (Fogarty et al. 1991). Humpback whale abundance in the northern Gulf of Maine increased dramatically during 1992-93 , along with a major influx of herring (College of the Atlantic, pers. comm.). Humpback whales were few in nearshore Massachusetts waters in the 1992-93 summer seasons, and more abundant in the offshore waters of Cultivator Shoal and Northeast Peak on Georges Bank, and Jeffreys Ledge — more traditional areas of herring occurrence (Center for Coastal Studies, pers. comm.). In 1996, small sand lance returned to the Stellwagen Bank area, and humpback whales were once again relatively abundant. However, unlike previous cycles, where an increase in sand lance corresponded to a decrease in herring, herring remained relatively abundant in the northern Gulf of Maine, and humpbacks correspondingly continued to occupy this portion of the habitat (unpublished data, Center for Coastal Studies and College of the Atlantic). Humpback whales, their habitat, and their prey are also linked by a diverse repertoire of feeding behaviors (Hain et al. 1982; Hain et al. 1995). A major research initiative was begun in early 1992 — the Years of the North Atlantic Humpback (YONAH) Project (Allen et al. 1993). This project is a large-scale, intensive, ocean-wide study of humpback whales throughout their entire |
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| Alternate Webpage(s) | https://www.nefsc.noaa.gov/nefsc/publications/tm/tm114/pdfs/10.pdf |
| Alternate Webpage(s) | http://www.nmfs.noaa.gov/pr/pdfs/sars/ao1997whhb-gme.pdf |
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| Alternate Webpage(s) | http://www.afsc.noaa.gov/nmml/PDF/sars/ao1995whhb-gme.pdf |
| Alternate Webpage(s) | http://www.nmfs.noaa.gov/pr/pdfs/sars/ao1995whhb-gme.pdf |
| Alternate Webpage(s) | https://www.afsc.noaa.gov/nmml/PDF/sars/ao1997whhb-gme.pdf |
| Alternate Webpage(s) | http://www.nefsc.noaa.gov/publications/tm/tm114/pdfs/10.pdf |
| Alternate Webpage(s) | http://www.afsc.noaa.gov/nmml/PDF/sars/ao1997whhb-gme.pdf |
| Alternate Webpage(s) | https://storestuff.s3.amazonaws.com/13200_98872306_1?AWSAccessKeyId=AKIAJBNEEVWEAALCCECQ&Expires=1580528546&Signature=cbxYph/HSH4h2P1Sgakd0EOElPg%3D&response-content-disposition=attachment%3B+filename%3D%22ao1997whhb-gme-508.pdf%22%3B+filename*%3DUTF-8''ao1997whhb-gme-508.pdf |
| Alternate Webpage(s) | https://www.afsc.noaa.gov/nmml/PDF/sars/ao1995whhb-gme.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
