getMSY {MQMF}

getMSY calculates the MSY for the Polacheck et al 1993 equation

Description

getMSY calculates the MSY for the Polacheck et al 1993 generalized surplus production equation. This simplifies to rK/4 when p = 1.0. But this is a general equation that covers off for all positive values of p.

Usage

getMSY(pars, p = 1)

Arguments

pars

the model parameters r, K, Binit, sigma; p is kept separate

p

asymmetry parameter for the Polacheck et al 1993 equation, default=1.0 = Schaefer

Value

the MSY

References

Polacheck, T., Hilborn, R., and A.E. Punt (1993) Fitting surplus production models: Comparing methods and measuring uncertainty. Canadian Journal of Fisheries and Aquatic Sciences, 50: 2597-2607.

Examples

param <- c(r=1.1,K=1000.0,Binit=800.0,sigma=0.075)
getMSY(param,p=1.0)     #  275       Schaefer equivalent
getMSY(param,p=1e-08)   #  404.6674  Fox equivalent