The Fratio MP with a controller that changes the level of F according to the relationship between Surplus production and biomass. Ie lower F when dSP/dB is positive and higher F when dSP/dB is negative.
DynF(x, Data, yrsmth=10, gg=2, reps = 100)A position in a data-limited methods object
A data-limited methods object
The number of historical recent years used for smoothing catch and biomass data
A gain parameter that modifies F according to the gradient in surplus production with biomass
The number samples of the TAC
A numeric vector of TAC recommendations
The method smoothes historical catches and biomass and then infers the relationship between surplus production and biomass (as suggested by Mark Maunder and Carl Walters). The approach then regulates a F based policy according to this gradient in which F may range between two different fractions of natural mortality rate.
The core advantage is the TAC(t) is not strongly determined by TAC(t-1) and therefore errors are not as readily propagated. The result is method that tends to perform alarmingly well and therefore requires debunking ASAP.
Made-up for this package.