Yet 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 modelling scenarios developed at the March 2008 IWC Workshop on Greenlandic Fisheries, also taking account of suggestions made at the subsequent March 2009 Workshop. Calculations have been performed for MSYR = 1% and 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 preexploitation abundance K is finite, so that standard likelihood profile estimates of lower confidence bounds for abundance are provided. Two different likelihood formulations are considered, termed Brandão and Schweder. Results yield lower values for lower bounds on K (and on N2007) for Model 3 (“redistribution”) than for Model 4b (“influx”). If results for Model 5 for the two strata are added, they are intermediate between those for Models 3 and 4b. Generally, use of the Brandão likelihood yields lower values of these lower bounds than does the Schweder likelihood function.
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Brandão, A., & Butterworth, D. S. (2009). Yet further results for lower confidence limits for the abundance of West Greenland minke whales. MARAM: University of Cape Town.