IT5 {DLMtool} R Documentation

## Iterative Index Target MP

### Description

An index target MP where the TAC is modified according to current index levels (mean index over last 5 years) relative to a target level.

### Usage

IT5(x, Data, reps = 100, plot = FALSE, yrsmth = 5, mc = 0.05)

IT10(x, Data, reps = 100, plot = FALSE, yrsmth = 5, mc = 0.1)

### 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 The number of historical years over which to average the index mc The maximum fractional change in the TAC among years.

### Details

The TAC is calculated as:

\textrm{TAC}_y = C_{y-1} I_δ

where C_{y-1} is the catch from the previous year and I_δ is the ratio of the mean index over the past yrsmth years to a reference index level. The maximum allowable change in TAC is determined by mc: e.g mc=0.05 means that the maximum change in TAC from the previous catch is 5%.

The reference index level (Data@Iref) is assumed to be a proxy for MSY. In the MSE Iref is the index at MSY subject to observation error (Obs@Irefbiascv). Consequently the performance of these methods in MSE is strongly determined by the uncertainty the in reference index.

### Value

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

### Functions

• IT5: Maximum annual changes in TAC are 5 per cent.

• IT10: Maximum annual changes are 10 per cent.

### Required Data

See Data-class for information on the Data object

IT5: Ind, Iref, MPrec

IT10: Ind, Iref, MPrec

### Rendered Equations

See Online Documentation for correctly rendered equations

T. Carruthers

### Examples

IT5(1, MSEtool::SimulatedData, plot=TRUE)
IT10(1, MSEtool::SimulatedData, plot=TRUE)

[Package DLMtool version 6.0.2 Index]