Stranding and mortality of 

 humpback whales, 

 Megaptera novaeangliae, 

 in the mid-Atlantic and southeast 

 United States, 1985-1992 



David N. Wiley 

 Regina A. Asmutis 



International Wildlife Coalition 



70 East Falmouth Highway, East Falmouth, Massachusetts 02536 



Thomas D. Pitchford 



Virginia Marine Science Museum 



7 1 7 General Booth Boulevard, Virginia Beach, Virginia 2345 1 

 Present address: Florida Department of Natural Resources 

 Florida Marine Research Institute, Marine Mammal Section 



Southwest Field Station, 1 4 1 8-G Market Circle, Port Charlotte, Florida 33954 



Damon P. Gannon 



Plymouth Marine Mammal Research Center 

 RO. Box 1131. Plymouth, Massachusetts 02362 



Marine mammal strandings are a 

 result of, or result in, mortality that 

 may be attributed to natural or an- 

 thropogenic factors. As such, strand- 

 ing data can provide insight on spa- 

 tial distribution, seasonal move- 

 ments, and mortality factors pertain- 

 ing to marine mammal populations 

 (Woodhouse, 1991; Mead 1 ). 



The general distribution and mi- 

 gratory movements of humpback 

 whales, Megaptera novaeangliae, in 

 the western North Atlantic are well 

 known from numerous studies 

 based on the identification of indi- 

 vidual animals and on other tech- 

 niques. Humpbacks feed in high 

 latitude areas during the summer 

 months, including waters of the 

 Gulf of Maine, eastern Canada, 

 West Greenland, and Iceland (Hain 

 et al., 1982; Martin et al., 1984; 

 Perkins et al., 1984; Katona and 

 Beard 1990). In the winter, whales 

 from all populations migrate to 



breeding grounds in the West 

 Indies (Balcomb and Nichols, 1982; 

 Mattila and Clapham, 1989; 

 Mattila et al., 1989; Katona and 

 Beard 1990). Between these migra- 

 tory end points, little is known of 

 the distribution of the species. In 

 recent years, however, there has 

 been an apparent increase in the 

 frequency of sightings of humpback 

 whales off the mid- Atlantic coast of 

 the United States (Swingle et al., 

 1993). Furthermore, a considerable 

 number of strandings have been 

 documented along the mid-Atlan- 

 tic and southeast coasts, many in 

 midwinter, a time when the major- 

 ity of humpbacks are thought to be 

 located in tropical waters. In this 

 paper, we analyze data from these 

 strandings, discuss implications 

 regarding distribution and possible 

 spatial segregation by age class, 

 and examine apparent causes of 

 mortality. 



Methods 



Study area and period 



The study covers the coastal area 

 of eastern North America extend- 

 ing from New Jersey(40°28'5N, 

 74°00'0W) to southern Florida 

 (25°12'N, 80°13'W), consisting of 

 2,319 km of coastline (Fig. 1). The 

 eight-year period from 1 January 

 1985 through 31 December 1992 

 was investigated. Stranding data 

 were obtained from the United 

 States Museum of Natural History, 

 Smithsonian Institution's Marine 

 Mammal Events Program (MMEP). 

 This information was confirmed 

 and augmented by comparison with 

 data from stranding response per- 

 sonnel involved with the Northeast 

 and Southeast Regional Stranding 

 Networks and with data published 

 in newspaper reports. Organiza- 

 tions involved in the regional 

 stranding networks operate under 

 a permit issued by the National 

 Marine Fisheries Service. The 

 names and organizations of inves- 

 tigators responding to specific 

 stranding events are on file. 



Analyses 



The following data were recorded 

 for each stranding: date, location, 

 sex, body length, and the presence 

 or absence of body markings that 

 may indicate a possible anthropo- 

 genic cause of mortality (e.g. ship 

 strike or fishery interaction). 



Stranding incidents among states 

 were compared by using a ratio of the 

 number of strandings in the state to 



1 Mead, J. G. 1979. An analysis of cetacean 

 strandings along the eastern coast of the 

 United States. In J. R. Geraci and D. J. 

 St. Aubin (eds.), Biology of marine mam- 

 mals: insights through strandings, p. 54- 

 68. Report to U.S. Marine Mammal 

 Comm. Contract MM7AC020. U.S. Dep. 

 of Commer, Natl. Tech. Info. Serv. PB-293 

 890. 



Manuscript accepted 15 June 1994. 

 Fishery Bulletin 93:196-205 (1995). 



196 



