| Summary: | The purpose of this study is to explore the implications of the historical perspective when it is linked to the ecological concept of adaptive management. The vehicle for this exploration is a genetically distinct population of killer whales (Orcinus orca), whose core coastal habitat includes the inland waters of Georgia Strait, Juan de Fuca Strait and Puget Sound; a geographic region referred to as the “Salish Sea.” This stock of killer whales, known as the Southern Resident Community, is unique in having a detailed scientific record that spans over two decades and recently this population was listed as “threatened” by the Committee on the Status of Endangered Wildlife in Canada (April 1999). The goal of this study is to take account of the specific ecological history of this killer whale population, and provide an assessment of the resiliency of this stock to withstand present levels of human impacts. In Chapter 1 the academic concepts of historical ecology and adaptive management are reviewed in preparation for their application as theory. Chapter 2 is an inventory of the ecological domain, in which the focal population is assessed by temporally measurable indicators o f its ecological status: population dynamics, feeding ecology, and habitat use. In Chapter 3 temporally measurable indicators of stress such as predation, disease, food resource depletion, toxic exposure, surface disturbance, and underwater noise are examined for their impact upon the carrying capacity of the environment of the whales. Chapter 4 plots both sets of indicators historically as trends in variation from the Sample Mean at different time scales (months, years, decades, centuries), and indexes them in terms of perturbations from the historical norm. In Chapter 5 four basic types of historical trends in environmental impacts are identified that are directly relevant to evaluating the resilience of the management unit. These are: (1) Relic impacts - potential impacts that are no longer present, but may account for present conditions. ...
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