getProduction: getProduction estimates MSY from output of ASPM

In haddonm/datalowSA: A Package to Faciliate Application of Data poor Stock Assessments

getProduction estimates MSY from output of ASPM

Description

getProduction takes the optimum estimate of R0 from ASPM and estimates the production curve, from which it gains the MSY, Bmsy, Hmsy, and Dmsy (depletion at MSY). It generate the production curve by stepping through the dynamics of the fishery over a series of constant harvest rates for however many iterations of nyr required.

Usage

getProduction(
  inR0,
  infish,
  inglb,
  inprops,
  Hrg = c(0.025, 0.4, 0.025),
  nyr = 50,
  maxiter = 3
)

Arguments

inR0	the optimum estimate of R0 from ASPM on nominal scale
infish	the fish data.frame from readdata or built in dataset
inglb	the glb data.frame from readdata or built in dataset
inprops	the props data.frame from readdata or built in dataset#'
Hrg	the desired sequence of harvest rates to be used to define the production curve. The default is c(0.025,0.4,0.025), but it is a good idea to plot teh harvest rate against yield and manually adjust the sequence values to focus attention and detail on where the MSY falls.
nyr	The number of years making up a single iteration while searching for the equilibrium yield. default = 50.
maxiter	defaults to 3. Determines how many runs through the nyr steps are conducted to reach equilibrium. One can trial different values but 3 is a reasonable compromise. It is best to test different maxiter values to ensure equilibria are reached in each yield estimate.

Value

a data.frame containing the sequence of harvest rates, the related spawning biomass, the exploitable biomass, the yield, and depletion.

Examples

## Not run: 
data(fishdat)
fish <- fishdat$fish
glb <- fishdat$glb
props <- fishdat$props
pars <- c(14,0.3)
bestL <- optim(pars,aspmLL,method="Nelder-Mead",infish=fish,inglb=glb,
               inprops=props,control=list(maxit=1000,parscale=c(10,0.1)))
prod <- getProduction(exp(bestL$par[1]),infish=fish,inglb=glb,inprops=props,
                      Hrg=c(0.0005,0.07,0.0005),nyr=50)
head(prod,20)
tail(prod,20)

## End(Not run)

haddonm/datalowSA documentation built on Nov. 5, 2023, 6:40 p.m.