DLMtool (version 5.2)

SPMSY: Catch trend Surplus Production MSY MP

Description

An MP that uses Martell and Froese (2012) method for estimating MSY to determine the OFL. Since their approach estimates stock trajectories based on catches and a rule for intrinsic rate of increase it also returns depletion. Given their surplus production model predicts K, r and depletion it is straighforward to calculate the OFL based on the Schaefer productivity curve.

Usage

SPMSY(x, Data, reps = 100, plot = FALSE)

Arguments

x

A position in a data-limited methods data object

Data

A data-limited methods data object

reps

The number of stochastic samples of the MP recommendation(s)

plot

Logical. Show the plot?

Value

An object of class Rec with the TAC slot populated with a numeric vector of length reps

Required Data

See '>Data for information on the Data object

SPMSY: Cat, L50, MaxAge, vbK, vbLinf, vbt0

Rendered Equations

See Online Documentation for correctly rendered equations

Details

The TAC is calculated as: $$\textrm{TAC} = D K \frac{r}{2}$$ where \(D\) is depletion, \(K\) is unfished biomass, and \(r\) is intrinsic rate of increasase, all estimated internally by the method based on trends in the catch data and life-history information.

Requires the assumption that catch is proportional to abundance, and a catch time-series from the beginning of exploitation.

Occasionally the rule that limits r and K ranges does not allow r-K pairs to be found that lead to the depletion inferred by the catch trajectories. In this case this method widens the search.

References

Martell, S. and Froese, R. 2012. A simple method for estimating MSY from catch and resilience. Fish and Fisheries. DOI: 10.1111/j.1467-2979.2012.00485.x

See Also

Other Surplus production MPs: Fadapt, Rcontrol, SPSRA, SPmod, SPslope

Examples

# NOT RUN {
SPMSY(1, Data=DLMtool::SimulatedData, plot=TRUE)
# }