112 



Maiuiuals — ()///■ Llvlni^ Rt'Siuirct'S 



For further information: 



J.A. Esles 



National Biological Service 

 University of California 

 Santa Cruz, CA 95U64 



marked individuals in tiie two regions indicate 

 that both age of first reproduction and annual 

 birth rate of adult females are similar. 

 Furthermore, the close similarity between the 

 theoretical maximum rate of increase and 

 observed rates of population increase for sea 

 otters in Washington, Canada, and portions of 

 Alaska suggests that mortality from birth to 

 senescence in these populations is quite low. In 

 contrast, rates of mortality in the California sea 

 otter are comparatively high, with an estimated 

 40%-50% of newborns lost before weaning 

 (Siniff and Ralls 1991; Jameson and Johnson 

 1993; Riedman et al. 1994). This alone would 

 significantly depress a population's potential 

 rate of increase. Furthermore, the age composi- 

 tion of beach-cast carcasses in California indi- 

 cates that most postweaning deaths occur well 

 in advance of physiological senescence (Pietz et 

 al. 1988; Bodkin and Jameson 1991 ). These pat- 

 terns likely explain the depressed rate of 

 increase in the California sea otter population. 



Although the demographic patterns of mor- 

 tality in California sea otters are becoming 

 clear, the causes of deaths remain uncertain. 

 There is growing evidence for the importance of 

 predation by great white sharks {Carcharodon 

 carchcirias). Contaminants may also be having 

 a detrimental effect on California sea otters, 

 although as yet there is no direct evidence for 

 this. However, polychlorinated biphenyl (PCB) 

 and DDT levels, known to be high in the 

 California Current, are also high in the liver and 

 muscle tissues of California sea otters (Bacon 

 1994). Of particular concern are that average 

 PCB levels in California sea otters approach 

 those that cause reproductive failure in mink, 

 which are in the same family as otters; and 

 preweaning pup losses are especially high in 

 primiparous {sec glossary) females. This latter 

 point may be significant because environmental 



contaminants that accumulate in fat can be 

 transferred via milk in extraordinarily high con- 

 centrations, especially to the first-born young in 

 species such as the sea otter which has pro- 

 longed sexual immaturity. 



References 



Bacon, C.E. 1994. An ecotoxicological comparison of 

 organic contaminants in sea otters [Enhxdra liitris) 

 among populations in California and Alaska. M.S. thesis. 

 University of California, Santa Cruz, .'i-'i pp. 



Bodkin. J.L.. and R.J. Jameson. 1991. Patterns of seabird 

 and marine mammal carcass deposition along the central 

 California coast. 1980-1986. Canadian Journal of 

 Zoology 69(.'S):II49-II55. 



Estes. J.A. 1990. Growth and equilibrium in sea otter popu- 

 lations. Journal of Animal Ecology 59:.^8,'i-40l. 



Jameson, R.J., and A.M. Johnson. I99_V Reproductive char- 

 acteristics of female sea otters. Marine Mammal Science 

 9(2): I. "56- 1 67. 



Kenyon. K.W. 1969. The sea otter in the eastern Pacific 

 Ocean. North American Fauna 68:1-352. 



Pietz. P.. K. Ralls, and L. Perm. 1988. Age determination of 

 California sea otters from teeth. Pages 106-1 15 //; D.B. 

 Siniff and K. Ralls, eds. Population status of California 

 sea oilers. Final report to the Minerals Management 

 Service, U.S. Department of the Interior 

 14-12-001-3003. 



Riedman. M.L., and J.A. Estes. 1990. The sea otter 

 [Enhydra liilris): behavior, ecology, and natural history. 

 U.S. Fish and Wildlife Service Biological Rep. 90(14). 

 1 26 pp. 



Riedman M.L.. J.A. Esles. M.M. Staedler. A. A. Giles, and 

 D.R. Carlson. 1994. Breeding patterns and reproductive 

 success of California sea otters. Journal of Wildlife 

 Management 58:-39 1 -399. 



Sinift D.B., and K. Ralls. 1991. Reproduction, survival, and 

 tag loss in California sea otters. Manne Mammal Science 

 7(3):2ll-229. 



Wendell, F.E., R.A, Hardy, and J.A. Ames. 1985. 

 Assessment of the accidental take of sea otters, Enhydra 

 liitris. in gill and trammel nets. Marine Research Branch, 

 California Department of Fish and Game. 30 pp. 



Wilson. D.E., M.A. Bogan, R.L. Brownell, Jr., A.M. Burdin, 

 and M.K. Maminov. 1991. Geographic variation in sea 

 otters, Enlndra lulris. Journal of Mammalogy 

 72( I ):22-36. 



White-tailed 

 Deer in the 

 Northeast 



by 



Gerald L. Storm 



National Biological Service 



William L. Palmer 



Pennsylvania Game 



Commission 



Populations of white-tailed deer (Odocoileus 

 virginianiis) have changed significantly 

 during the past 100 years in the eastern United 

 States (Halls 1984). After near extirpation in the 

 eastern states by 1900, deer numbers increased 

 during the first quarter of this century. The 

 effects of growing deer populations on forest 

 regeneration and fami crops have been a con- 

 cern to foresters and farmers for the past 50 

 years. 



In recent years, deer management plans have 

 been designed to maintain deer populations at 

 levels compatible with all land uses. Confiicts, 

 however, between deer and forest management 

 or agriculture still exist in the Northeast. Areas 

 that were once exclusively forests are now a 

 mixture of forest, farm, and urban environments 



that create increased interactions and conflicts 

 between humans and deer, including deer-vehi- 

 cle collisions. Management of deer near urban 

 environments presents a unique challenge for 

 local resource managers (Porter 1991 ). 



This report describes trends in abundance of 

 white-tailed deer in the northeastern United 

 States, relationships between harvest and popu- 

 lation estimates, and conflicts between deer and 

 other resources. 



Data Surveys 



We contacted biologists in each of 13 north- 

 eastern states to acquire estimates of deer popu- 

 lation size, harvest, and deer-vehicle collisions. 

 We featured harvest data for antlered deer from 



