UNIT 24 

 MARINE MAMMALS OF THE ATLANTIC REGION AND THE GULF OF MEXICO 



Current Population Trend 



Based on recent aerial survey counts during 

 the May-June pupping season along the Maine 

 coast, harbor seal abundance in U.S. waters is in- 

 creasing, but the actual trend is unknown. 



Status of Stock 



PBR (Barlow et al., 1995) was specified as the 

 product of minimum population size (30,990), 

 one-halt the ma.xinium productivity rate (0.06), 

 and a recovery factor of 1.0, to give a PBR lor this 

 stock of 1,859 harbor seals (Waring et al., 1997). 



The status of the harbor seal population, rela- 

 tive to the optimum sustainable population, in the 

 U.S. Atlantic Exclusive Economic Zone is un- 

 known, but the population is increasing. The spe- 

 cies is not listed as threatened or endangered un- 

 der the Endangered Species Act. The estimated 

 annual level of human-caused mortality and seti- 

 ous injury in U.S. waters does not exceed PBR; 

 therelore, this is not a strategic stock. 



NORTHERN RIGHTWHALE: 

 NORTH ATLANTIC STOCK 



Historical Background 



Ihe northern right whale was the first large 

 whale to be hunted on a systematic, commercial 

 basis. The species was taken by Basque whalers in 

 the Bay of Biscay at least as early as the 1 1 th cen- 

 tury (Aguilar, 1986). By the late 1 500's the Basques 

 had established a substantial fishery off the Labra- 

 dor coast (Cumbaa, 1986). This was succeeded 

 by intensive shore whaling ot( New England in 

 the 17th and 18th centuries, an activity which 

 continued sporadically into the early part of this 

 century. Similarly intensive exploitation occurred 

 in the North Pacific population beginning in 1 835. 

 Although the right whale was officially protected 

 throughout its range in 1935, it is now known 

 that the former Soviet Union took substantial 

 numbers of these animals in the North Pacific and 

 Sea of Okhotsk into the 1960's (Yablokov, 1994). 

 There is presently no evidence that these illegal 

 catches extended to the North Atlantic. 



Stock Definition 



and Geographic Range 



The right whale is a slow animal which fre- 

 quents coastal and shelf habitats. It feeds in tem- 

 perate or high latitudes in summer and calves in 

 warmer water in winter. The North Atlantic popu- 

 lation is generally thought to consist of two rela- 

 tively discrete stocks in the eastern and western 

 portions of this ocean basin. 



Historically, right whales were found in coastal 

 waters throughout the North Atlantic in a range 

 which extended from Florida (and perhaps fur- 

 ther south) to Greenland in the west, and from 

 western Africa to Norway in the east. However, 

 intensive exploitation has greatly reduced the range 

 of this animal. In the western North Atlantic, the 

 remaining population is today largely confined to 

 U.S. and Canadian waters, feeding in the Gulf of 

 Maine and on the Scotian Shelf and calving in 

 the coastal waters of Georgia and Florida (Kraus 

 et al., 1986b; Winn et al., 1986). Right whales 

 appear in the Cape Cod and Massachusetts Bays 

 region in late winter, move to the Great South 

 Channel (southeast of Cape Cod) in spring, and 

 then migrate to Canadian waters for the summer. 

 The Bay of Fundy constitutes a major summer 

 nursery area for the population, although recent 

 genetic studies suggest the existence of a second, 

 unidentified nursery (Schaeffet al., 1993). In win- 

 ter, pregnant females migrate to give birth off the 

 southeastern United States; although other whales 

 are also found there at this time, the whereabouts 

 of a substantial portion of the population in win- 

 ter remains unknown. 



In the eastern North Atlantic, right whales are 

 rarely observed today and the stock appears to be 

 close to extinction. Historically, the species fed in 

 northern European and Icelandic waters and was 

 believed to have calved off the west coast of Africa 

 (Reeves and Mitchell, 1986). 



Female right whales are sexually mature be- 

 tween about 4 and perhaps 12 years of age, and 

 produce a single calf on average every 3-4 years 

 (Knowlton et al., 1994); this is a significantly 

 slower rate of reproduction than that of the 

 rorquals (Lockyer, 1984). The right whale is 



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