WFC 154 Lecture 14: Lecture 14-10/24
10 Nov 2016
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Document Summary
W/ proportional quota- exploitation risk is low for many years. W/constant quota- after a while the over-harvesting risk increases. Valuable, one fish sold for ,000 at tokyo fish market. As population decline, the per unit cost of hunting/fishing rises dramatically. This will lead to reduced hunting/fishing pressure. Assumes that value of items does not increase dramatically with scarcity. Many species are prized for unique reasons. Despite greater cost of finding them, their worth provides incentive to drive them to extinction rather than preserve living animals for sustained value. Population must remain about minimal viable size. Population should retain its functional ecosystem role. Size and age structure, sex ratios must not be altered. Darwinian debt: the long timescale for recovering from harmful genetic changes caused by exploitative selection (artificial selection such as hunting) One year of hunting takes multiple years to recover lost genes and phenotypic variation. Impacts of lost upper size/ age classes. Example is from rock lobsters in aus.
