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Development of freshwater recruitment curves

Notes:

Age class abundance were estimated by WDFW annually from 1991 to 2005 for the Upper Yakima mainstem. For the time being, length and age class relationships were extrapolated to the tributaries for the purpose of estimating total Upper Yakima age class abundance. Four different recruitment curves were constructed from these annual age class abundance estimates representing recruitment from egg deposition to 1 yr, 1 yr to 2yr, 2yr to 3 yr and 3 yr to 4+ yrs of age. Again, these curves are capturing density dependent effects constrained by the habitat’s capacity and productivity through intra-specific competition between all omykiss juveniles destined for either ecotypes. Negative log-likelihood was used to fit curves to recruitment data points.