Intersection Model for Estimating Sea Otter Mortality from the EXXON VALDEZ OilSpill Along the Kenai Peninsula, Alaska. Marine Mammal Study 6-5. EXXON VALDEZ Oil Spill State/Federal Natural Resource Damage Assessment Final Report

摘要

The authors developed an analytical model (intersection model) to estimate theexposure of sea otters (Enhydra lutris), to oil from the Exxon Valdez oil spill. The authors applied estimated and assumed exposure dependent mortality rates to the Kenai Peninsula sea otter population to provide examples of the application of the model in estimating sea otter mortality. The intersection model requires three distinct types of data: (1) distribution, abundance, and movements of oil, (2) abundance and distribution of sea otters, and (3) sea otter mortality rates relative to oil exposure. Initial output of the model is an estimate of exposure of otters to oil. Exposure is measured in amount and duration of oil near an otter's observed location (intersections). The authors provide two examples of the model using different assumptions about the relation between exposure and mortality. Because of an apparent non-linear relation between the degree of oiling and survival of otters from rehabilitation, output from the authors' examples are likely biased.