204 



Fishery Bulletin 93(1), 1995 



occur most frequently (Virginia and North Carolina), 

 often in water depths of less than 20 m. In Florida, 

 the concentration of strandings occurs in the vicinity 

 of active commercial and military shipping and where 

 ship strikes have been reported to represent a hazard 

 to northern right whales (Kraus and Kenney, 1991). 



Entanglement in commercial fishing gear has been 

 the most frequently identified anthropogenic cause 

 of injury and death in humpback whales; gillnet-type 

 gear most often was implicated (O'Hara et al., 1986). 

 Coastal gillnet fisheries exist in the study area on a 

 year-round basis, but effort may peak in late winter/ 

 spring (NMFS, 1992; Swingle et al., 1993; Brooks 16 ). 

 Over 2,200 gillnet licenses have been issued for the 

 mid-Atlantic coastal region. However, fishermen may 

 hold more than one permit and some coastal fisher- 

 ies do not require permits (NMFS, 1992). In the study 

 area, coastal gill nets and whales concurrently oc- 

 cupy waters of less than 15 m in depth (observed by 

 RAA and DPG), and whales have been observed trail- 

 ing such gear (Swingle 17 ). The association of young, 

 inexperienced whales with gill nets in shallow waters 

 may increase the potential for entanglement incidents. 

 Since entanglement mortality is inversely related to 

 body size (Lien et al., 1989; Kraus 1990b), juvenile 

 humpbacks may be more susceptible to fatalities. 



Data contained in this paper suggest that mid-At- 

 lantic and southeast coastal areas of the United 

 States are becoming increasingly important habitat 

 for juvenile humpback whales and that anthropo- 

 genic factors may negatively impact these animals. 

 However, there are a number of factors that suggest 

 caution should be used in interpretation of these data. 

 The site of stranding is not necessarily the site of 

 death, as the body of a large whale can be carried 

 considerable distances by wind and currents before 

 beaching occurs. Cause of death in the stranded ani- 

 mals was rarely determined with certainty and in 

 most cases was inferred from observations of the 

 presence or absence of surface body trauma, not from 

 thorough necropsy by experienced individuals. A 

 greater emphasis should be placed on complete 

 necropsies of stranded animals to determine not only 

 the immediate cause of death but also whether there 

 is an underlying factor in the fatality. This would 

 allow a more reliable investigation into mortality and 

 provide greater ability to evaluate and alleviate the 

 impact of anthropogenic interactions. This is particu- 

 larly important for an endangered species, such as 

 the humpback whale. 



16 Brooks, W. Florida Department of Environmental Protection, 

 Jacksonville, FL 32216. Personal commun., September 1993. 



17 Swingle, W. Virginia Marine Science Museum, Virginia Beach, 

 VA 23451. Personal commun., March 1992. 



Acknowledgments 



The authors thank James G. Mead of the Smith- 

 sonian Institution for access to data contained in the 

 Marine Mammal Events Program. We also thank the 

 many individuals who comprise the Northeast and 

 Southeast Regional Stranding Networks. Phil 

 Clapham, Colleen Coogan, Sharon Young, and two 

 anonymous reviewers provided comments which 

 greatly improved the manuscript. 



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