The TAC is adjusted by the ratio alpha, where the numerator is the mean length of the catch (of lengths larger than Lc) and the denominator is the mean length expected when FMSY = M and M/K = 1.5. Natural mortality M and von Bertalanffy K are not used in this MP (see Appendix A of Jardim et al. 2015). Here, Lc is the length at full selection (LFS).
Lratio_BHI(x, Data, reps, yrsmth = 3)A position in data-limited methods data object
A data-limited methods data object
The number of TAC samples
The most recent years of data to smooth the calculation of the mean length
Argument yrsmth currently takes the mean length of the most recent 3 years of data as a smoother.
Ernesto Jardim, Manuela Azevedo, Nuno M. Brites, Harvest control rules for data limited stocks using length-based reference points and survey biomass indices, Fisheries Research, Volume 171, November 2015, Pages 12-19, ISSN 0165-7836, https://doi.org/10.1016/j.fishres.2014.11.013