PARENT SESSION
Oral Session #92: Conservation Ecology: Genetics, population viability, interactions.
Presiding: W. Wirtz
Thursday, August 8. 1:00 PM to 3:45 PM. Grand Ballroom West, Radisson.

Mortality sensitivity in life- stage simulation analysis: A case study of southern sea otters .

Gerber, Leah^*,1, Tinker, Tim², Doak, Dan², Estes, James², ¹ Department of Biology, Tempe, AZ² Department of Biology, Santa Cruz, CA

ABSTRACT- We use life stage simulation analysis to examine 30 years of age and sex specific mortality data for Southern sea otters. Population recovery of the southern sea otter has been slow compared to other recovering otter populations and since 1995 the population has declined. We present a demographic model for examining the sensitivity of sea otter population growth to putative sources of mortality (e.g., trauma, disease, fisheries, gun shot, mating trauma, shark bites. We use resampling simulations to generate random combinations of vital rates for a large number of matrix replicates, and use these to estimate potential effects of mortality sources on . Elasticity values obtained for Southern sea otters indicate that the population is far more sensitive to changes in survival rates than reproduction. Disease, emaciation and shark bites explained a substantial fraction of variance in . Understanding the role of mortality sources for southern otters helps focus attention on the sources of mortality that can and cannot be controlled in recovery efforts.

KEY WORDS: endangered species, population viability, demographic sensitivity analysis, disease