Further results for lower confidence limits for the abundance of West Greenland minke whales
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2009
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University of Cape Town
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Abstract
The methodology advanced by Brandão and Butterworth (2007 and 2008) for simulating catch sex sampling data in the process of computing lower confidence bounds for the abundance of the West Greenland minke whale population is applied to the new modelling scenarios developed at the March 2008 IWC Workshop on Greenlandic Fisheries. To date calculations have extended only to MSYR = 2%, and been implemented for Models 3, 4b and 5 for the age-structured population model of Witting and Schweder (2008). For Model 5 for the SW stratum treated as an independent stock, the MLE of pre-exploitation abundance K is finite, so that standard likelihood profile estimates of lower confidence bounds for abundance are provided. Lower bounds for Model 4b (the “influx” model) are higher than for Model 3 (the “redistribution” model. Non-convergence of some of the Model 3 fits required to compute the deviance distributions which are used to determine the confidence bounds still persist, but time constraints have precluded further investigation of suggestions put forward in IWC (2008b).
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Brandao, A., & Butterworth, D. S. (2009). Further results for lower confidence limits for the abundance of West Greenland minke whales. IWC document SC-M09-AWMP4.