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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Dear all,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Sometime soon, I’m faced with another Management Plan Evaluation for North Sea herring. Obviously we’ll be using FLR. However, I’d like to gain a bit more insight into good
practices to ‘estimate’ a specific biomass reference point, so it is a bit off-topic but the expertise in this group is so high I could not resist sending this question!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">The current HCR prescribes an Fbar of 0.1 below Blim (determined on a biological basis) and increases linearly with SSB up to a Btrigger biomass point (determined in 2008
based on a performance basis, i.e. scenario testing, which scenario performed best). Above this Btrigger, the HCR prescribes an Fbar of 0.25 (considered Fmsy).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Within the new evaluation, Blim, Btrigger and Fmsy will be a point of discussion (because the stock assessment changed considerably). I have some ideas on how to estimate
Blim and Fmsy, but with Btrigger I’m a bit in the dark. What I can think of so far is to run stochastic equilibrium simulation assuming constant Fs (over a range) and, as a first guess, taking Btrigger as the median equilibrium SSB. Does this make sense, and
if not, what would you suggest to do. I need some sort of approach to link potential Ftrigger points to Btrigger points because else I will be running far too many scenarios to be able to analyse and discuss later on.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Many thanks in advance for your suggestions.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Kind regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Niels<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><o:p> </o:p></span></p>
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