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Model DescriptioNDocument tion <br />The general model consists of 14 geomorphic units; 5 for the Yampa subpopulation <br />(upper Green River arm), 4 for the lower Green River subpopulation and 5 in the <br />Colorado River arm. Specific spawning areas are defined by setting reproductive <br />output to some number greater than zero at each river segment. This general model <br />can be parameterized for each species independently. The model allows for age- <br />specific mortality inputs including: drifting mortality; mortality associated with transition <br />from eggs to the larval stage, larvae to YOY, YOY to 1-yr, 1-2 yr, 2-yr old to 3-yr, and <br />finally, subadult to adult transition mortality. <br />Carrying capacities are entirely unknown quantities to date, yet are essential for logistic <br />population growth equation dynamics. To estimate carrying capacities for each <br />geomorphic section, we initially ranked each unit based entirely on the expertise of the <br />biologists present at the workshops. These numbers were then transformed into `total <br />numbers of fish units' by asking the participants to estimate the maximum potential <br />densities for each section. The carrying capacity parameter then limits how many fish <br />of each age class can persist within a particular geomorphic reach. For example, if the <br />canrying capacity for a section were estimated to be 10, that unit could contain 10 <br />adults, 100 3-yr old fish, 1000 2-yr old fish, etc. or some combination of those. The <br />specific age-class distribution is dependent on the specific carrying capacity variables <br />for each age class. It should be noted that the carrying capacity values represent inter- <br />6 <br />