University of Cape Town
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SCRS_2020_164_Butterworth_Rademeyer.pdf (2.97 MB)

A possible approach to address the poor performance of CMPs under some R3 Oms.

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posted on 2023-05-11, 10:11 authored by Doug ButterworthDoug Butterworth, Rebecca A Rademeyer

Most instances of poor conservation performance of CMPs over the interim grid occur for OMs for which there is a regime shift in the future (the R3 scenario), and also a low abundance scale is assumed for the West area. To improve that performance would require a considerable sacrifice in catch for the other OMs. As a basis to avoid that, the the IWC approach of an “acceptable with research” CMP is put forward. In this case, this would involve tuning under the R1 and R2 OMs only, with implementation over a short initial period where both the an annual index of the proportion of Western origin bluefin in the West area is put in place to provide a basis able to detect a regime shift in the Eastern stock, and close-kin genetics is developed further to provide an improved estimate of the abundance of the Western stock in absolute terms.

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Department of Mathematics and Applied Mathematics, University of Cape Town