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Initial Results in the Development of a Revised OMP for Tristan da Cunha island rock lobster

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posted on 2022-02-28, 05:13 authored by Susan HollowaySusan Holloway, Doug ButterworthDoug Butterworth
An OMP for setting the TAC for the rock lobster fishery at Tristan da Cunha island was developed and implemented in 2013 (Johnston and Butterworth 2013). The operating model (i.e. the underlying stock assessment model used to simulation test the candidate OMPs) at the time (OM_2013) was fitted to GLM standardized CPUE for the period 1994 2012. This OM predicted catch rates for the fishery into the future (2013+) for the final selected OMP (OMP 2013). Recently, an updated GLM CPUE analysis (Johnston et al. 2015) has provided GLM standardized CPUE value for 2013 and 2014 – which are outside the 90% CI predicted by OM_2013. Table 1 and Figure 1 (top plot) report this discrepancy. This constitutes “exceptional Circumstances”, and requires initiation of a revision of OMP 2013. To initiate this process, results of the current OMP (OMP 2013) and variants thereof are reported here for three different OMs.



Department of Mathematics and Applied Mathematics, University of Cape Town