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Surplus Production Stock Reduction Analysis

SPSRA.Rd

A surplus production equivalent of DB-SRA that uses a demographically derived prior for intrinsic rate of increase (McAllister method, below)

Usage

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

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

Arguments

x

A position in the data object

Data

A data object

reps

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

plot

Logical. Show the plot?

Value

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

Details

The TAC is calculated as: $$\textrm{TAC} = K D \frac{r}{2}$$ where \(K\) is estimated unfished biomass, \(D\) is depletion, and \(r\) is the estimated intrinsic rate of increase.

Like all SRA methods, this MP requires a time-series of catch extending from the beginning of exploitation.

Functions

  • SPSRA: Base version. Requires an estimate of current depletion

  • SPSRA_ML: Variant that uses a mean-length mortality estimator to obtain a prior for current stock depletion.

Required Data

See Data-class for information on the Data object

SPSRA: Cat, Dep, FMSY_M, L50, MaxAge, Mort, steep, vbK, vbLinf, vbt0, wla, wlb

SPSRA_ML: CAL, Cat, Dep, FMSY_M, L50, Lbar, Lc, MaxAge, Mort, Year, steep, vbK, vbLinf, vbt0, wla, wlb

Rendered Equations

See Online Documentation for correctly rendered equations

References

McAllister, M.K., Pikitch, E.K., and Babcock, E.A. 2001. Using demographic methods to construct Bayesian priors for the intrinsic rate of increase in the Schaefer model and implications for stock rebuilding. Can. J. Fish. Aquat. Sci. 58: 1871-1890.

See also

Other Surplus production MPs: Fadapt(), Rcontrol(), SPMSY(), SPmod(), SPslope()

Author

T. Carruthers

Examples

SPSRA(1, MSEtool::SimulatedData, plot=TRUE)

#> TAC (median) 
#>      1106.57 
SPSRA_ML(1, MSEtool::SimulatedData, plot=TRUE)

#> TAC (median) 
#>     4005.328