STOCK DEFINITION AND GEOGRAPHIC RANGE
This stock is found in U.S. and Canadian Atlantic waters. During summer (July to September), harbor porpoises are concentrated in the northern Gulf of Maine and southern Bay of Fundy region, generally in waters less than 150 m deep (Gaskin 1977; Kraus et al. 1983; Palka 1995b). During fall (October-...
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| Format: | Text |
| Language: | English |
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1997
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.434.7047 http://www.nefsc.noaa.gov/publications/tm/tm114/pdfs/134.pdf |
| Summary: | This stock is found in U.S. and Canadian Atlantic waters. During summer (July to September), harbor porpoises are concentrated in the northern Gulf of Maine and southern Bay of Fundy region, generally in waters less than 150 m deep (Gaskin 1977; Kraus et al. 1983; Palka 1995b). During fall (October-December) and spring (March-June), harbor porpoises are widely dispersed from North Carolina to Maine, where the density is much lower than during the summer. No specific migratory routes to the northern Gulf of Maine/lower Bay of Fundy region have been documented. Harbor porpoises are seen from near the coastline into the middle of the Gulf of Maine (>200 m deep) in both spring and fall. During winter (January to February), intermediate densities of harbor porpoises are in waters off New Jersey to North Carolina, and low densities are found in waters off New York to New Brunswick, Canada as documented by sighting surveys, strandings, and takes reported by NMFS observers in the Sea Sampling Program. There were two stranding records from Florida (Smithsonian strandings data base). Gaskin (1984, 1992) proposed that there were four separate populations in the western North Atlantic: the Gulf of Maine/Bay of Fundy, Gulf of St. Lawrence, Newfoundland and Greenland populations. Recent analyzes involving mtDNA, organochlorine contaminants, and life history parameters support Gaskin’s proposal. In particular, there is a suggestion that the Gulf of Maine/Bay of Fundy females are different than Gulf of St. Lawrence females, but males were statistically indistinguishable (Palka et al. 1996). Research on microsatellites, a potentially powerful genetic tool, is currently being conducted to re-analyze existing genetic data and analyze new samples in order to resolve the larger scale stock structure question. This report follows Gaskin's hypothesis on harbor porpoise stock structure in the western North Atlantic; Gulf of Maine and Bay of Fundy harbor porpoises are recognized as a single management stock separate from harbor ... |
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