increase in the rate of beachings could result in a doubling to more than five times increase 

 in numbers recovered. It is generally assumed that the stranding recovery rate is an index 

 of the mortality rate. However, in a large complex system with a large population of animals 

 available to strand, the variability in the stranding rate may be more sensitive to factors 

 which cause carcasses to drift to the beach than to changes in the mortality rate. 



Changes in the pattern and causes of mortality may be a more reliable indicator of 

 anomalous mortality events than increases (which do not deviate from the seasonal pattern) 

 in the number of stranded animals. Both of these conditions were evident during the 1987-88 

 east coast bottlenose dolphin dieoff (Geraci, 1989; Scott et al., 1988). The occurrence of the 

 1987-88 strandings deviated from the normal pattern, and the pathology associated with the 

 strandings was unusual. Neither of these conditions were evident in the 1990 Gulf of Mexico 

 bottlenose dolphin strandings. 



Literature Cited 



Geraci, J.R. 1989. Clinical investigation of the 1987-88 mass mortality of bottlenose dolphins 

 along the U.S. central and south Atlantic coast Final Report to NMFS, ONR, and 

 MMC. 



Hersh, S.L. 1987. Mortality, natahty, migration and organismic growth rates of bottlenose 

 dolphins (Genus Tursiops): a review and management considerations. NMFS/SEFC 

 Miami, Contract Report No. 40-GENF-700715. 



Scott, G.P., D.M. Bum and L.J. Hansen. 1988. The dolphin dieoff: long-term effects and 

 recovery of the population. Pages 819-823 in Proceedings of the Oceans '88 

 Conference, Baltimore, MD. IEEE Catalog No. 88-CH2585-8. 



Scott, G.P., D.M. Bum, L.J. Hansen and R.E. Owen. 1989. Estimates of bottlenose dolphin 

 abundance in the Gulf of Mexico from regional aerial surveys. NMFS/SEFC Miami 

 Contribution No. CRD-88/89-07. 



Snedecor, G.W. and W.G. Cochran. 1973, Statistical methods, 6'*' ed. Iowa State University 

 Press, Ames, Iowa. 593 pp. 



Wells, R.S. and M.D. Scott. 1988. Estimating bottlenose dolphin population parameters from 

 individual identification and capture-release techniques. NMFS/SEFC Miami Contract 

 Report No. 50-WCNF-7-06083. 



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