Including length based idicators and methods in JABBA
L Kell
07 February, 2023
Outline
b.prior = c(1, 0.3, 1970, “ffmsy”) where 1970 is e.g. the start year then just set psi = c(0.2,3
- The method: i.e. examples for 3 stocks where we compare JABBAZ to JABBA-COM and JABBA. We can do this using TSS & AUC
- Risk Equivalence: the probability of a stock being depleted below a limit reference point or not being maintained at a target reference point, irrespective of the stock assessment method, the amount of data and knowledge available. I.e. ideally all methods should provide the same point estimates of F/FMSY & B/BMSY, only the CIs should change. So to have a 95% P of B>Blim then you must reduce yield. So there is value in information.
Condition Operating Model on life histories
Length frequency distribution
Figure 1. Time series, with MSY reference points.
Figure 2 Length data
Length based indicator
Figure 3. Comparison of lenght based indicatotrs with F.
True skill score and Area under the ROC curve
save(lhat,om,eq,lbi,lfd,lhs,file="/home/laurence-kell/Desktop/tmp/t.RData") 
Figure 4. True skill score
Figure 5. Area under the ROC curve
priors
Estimate Z
Figure 6.
><> jbplot_ppist() - prior and posterior distributions <><
Figure 7.
Figure 8.
Figure 9.