SPMSY {DLMtool} R Documentation

## 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 straight forward to calculate the OFL based on the Schaefer productivity curve.

### Usage

SPMSY(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?

### 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.

### Value

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

### Required Data

See Data-class for information on the Data object

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

### Rendered Equations

See Online Documentation for correctly rendered equations

T. Carruthers

### 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

Other Surplus production MPs: Fadapt(), Rcontrol(), SPSRA(), SPmod(), SPslope()
SPMSY(1, Data=MSEtool::SimulatedData, plot=TRUE)