Chapter III 



SPECIES OF SPECIAL CONCERN 



Section 202 of the Marine Mammal Protection Act 

 directs the Marine Mammal Commission, in consulta- 

 tion with its Committee of Scientific Advisors on 

 Marine Mammals, to make recommendations to the 

 Department of Commerce, the Department of the 

 Interior, and other agencies on actions needed to 

 protect marine mammals. To help meet this charge, 

 the Commission devotes special attention to particular- 

 ly vulnerable species and populations. Such species 

 may include marine mammals listed as endangered or 

 threatened under the Endangered Species Act, or 

 depleted under the Marine Mammal Protection Act 

 (Table 1), as well as others species or populations 

 facing special conservation challenges. 



During 1995 special attention was directed to a 

 number of endangered, threatened, or depleted species 

 or populations found in the United States and else- 

 where. These include Florida manatees, Hawaiian 

 monk seals, Steller sea lions, northern fur seals, sea 

 otters, northern right whales, humpback whales, 

 bowhead whales, and vaquitas. Other species not 

 listed but which nonetheless received special attention 

 in 1995 include harbor seals in Alaska, Pacific wal- 

 ruses, gray whales, harbor porpoises in the Gulf of 

 Maine, beluga whales, and polar bears. 



Florida Manatee 

 (Trichechus manatus latirostris) 



The Florida manatee, one of two distinct subspe- 

 cies of the West Indian manatee, occurs only in 

 coastal waters and rivers in the southeastern United 

 States. The other subspecies, the Antillean manatee 

 (T. manatus manatus), occupies the remainder of the 

 species' range in the Greater Antilles in the Caribbe- 

 an, the east coast of Central America, and the north- 

 east coast of South America. As herbivorous marine 

 mammals, West Indian manatees feed on underwater 



grass beds, marsh grasses, and algae, and can exceed 

 lengths of 3.5 meters (11.5 feet) and weights of 1,000 

 kilograms (2,200 pounds). 



Florida manatees exhibit a high degree of indepen- 

 dence in their movements. In winter, when water 

 temperatures fall below about 68 degrees, they aggre- 

 gate at localized warm-water refuges, principally in 

 the southern portions of their range. Preferred winter 

 refuges for most animals include natural warm-water 

 springs and heated outfalls from industrial facilities, 

 such as power plants and paper mills. A few animals 

 use warm-water refuges as far north as southern 

 Georgia. Some animals also occur at the southern tip 

 of Florida in the Florida Everglades where water 

 temperatures stay above 68 degrees year-round. As 

 water temperatures rise in spring, manatees begin to 

 disperse throughout Florida, and by late spring and 

 summer, some animals migrate hundreds of kilometers 

 northward up the Atlantic coast or westward along the 

 northern rim of the Gulf of Mexico at least as far as 

 the Texas coast. 



The manatee population in the southeastern United 

 States is the species' largest known concentration. In 

 1992, during a severe winter cold front when most 

 manatees were thought to be at warm- water refuges, 

 the State of Florida organized a two-day aerial survey 

 of known winter manatee habitats in Florida and 

 Georgia. The synoptic survey yielded a count of 

 1,856 animals with approximately equal numbers on 

 the Atlantic and Gulf of Mexico coasts. Similar 

 counts in 1991 and earlier in 1992 produced lower 

 numbers. In January 1995 the Florida Department of 

 Environmental Protection conducted a fourth survey, 

 yielding a count of 1,443 animals, including 665 

 animals on the east coast and 778 animals on the west 

 coast. Although lower counts were obtained, there 

 was a general consensus that this was due to sampling 

 variability rather than a decrease in population size. 



