Islope1 {DLMtool}

Index Slope Tracking MP

Description

A management procedure that incrementally adjusts the TAC to maintain a constant CPUE or relative abundance index.

Usage

Islope1(x, Data, reps = 100, plot = FALSE, yrsmth = 5, lambda = 0.4, xx = 0.2)

Islope2(x, Data, reps = 100, plot = FALSE, yrsmth = 5, lambda = 0.4, xx = 0.3)

Islope3(x, Data, reps = 100, plot = FALSE, yrsmth = 5, lambda = 0.4, xx = 0.4)

Islope4(x, Data, reps = 100, plot = FALSE, yrsmth = 5, lambda = 0.2, xx = 0.4)

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?

yrsmth

Years over which to calculate index

lambda

A gain parameter controlling the speed in update in TAC.

xx

Parameter controlling the fraction of mean catch to start using in first year

Details

The TAC is calculated as:

\textrm{TAC} = \textrm{TAC}^* \left(1+\lambda I \right)

where \textrm{TAC}^* is 1-xx multiplied by the mean catch from the past yrsmth years for the first year and catch from the previous year in projection years, \lambda is a gain parameter, and I is the slope of log index over the past yrsmth years.

Value

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

Functions

• Islope1: The least biologically precautionary of the Islope methods

• Islope2: More biologically precautionary. Reference TAC is 0.7 average catch

• Islope3: More biologically precautionary. Reference TAC is 0.6 average catch

• Islope4: The most biologically precautionary of the Islope methods. Reference TAC is 0.6 average catch and gain parameter is 0.2

Required Data

See Data-class for information on the Data object

Islope1: Cat, Ind, LHYear, Year

Rendered Equations

See Online Documentation for correctly rendered equations

Author(s)

T. Carruthers

References

Carruthers et al. 2015. Performance evaluation of simple management procedures. ICES J. Mar Sci. 73, 464-482.

Geromont, H.F., Butterworth, D.S. 2014. Generic management procedures for data-poor fisheries; forecasting with few data. ICES J. Mar. Sci. doi:10.1093/icesjms/fst232

See Also

Other Index methods: GB_slope(), GB_target(), Gcontrol(), ICI(), Iratio(), Itarget1_MPA(), Itarget1(), ItargetE1()

Examples

Islope1(1, MSEtool::SimulatedData, plot=TRUE)
Islope2(1, MSEtool::SimulatedData, plot=TRUE)
Islope3(1, MSEtool::SimulatedData, plot=TRUE)
Islope4(1, MSEtool::SimulatedData, plot=TRUE)