# LstepCE1: Step-wise Constant Effort In DLMtool: Data-Limited Methods Toolkit

## Description

A management procedure that incrementally adjusts the total allowable effort (TAE) according to the mean length of recent catches.

## Usage

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19``` ```LstepCE1( x, Data, reps = 100, plot = FALSE, yrsmth = 5, stepsz = 0.05, llim = c(0.96, 0.98, 1.05) ) LstepCE2( x, Data, reps = 100, plot = FALSE, yrsmth = 5, stepsz = 0.1, llim = c(0.96, 0.98, 1.05) ) ```

## 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 trend in mean length. `stepsz` Parameter controlling the size of update increment in effort. `llim` A vector of length reference points that determine the conditions for increasing, maintaining or reducing the effort.

## Details

The TAE is calculated as:

where \textrm{TAE}^* is effort in the previous year, S is step-size determined by `stepsz`, and r is the ratio of L_\textrm{recent} and L_\textrm{ave} which are mean length over the most recent `yrsmth` years and 2 x `yrsmth` historical years respectively.

The conditions are specified in the `llim` argument to the function.

## Value

An object of class `Rec` with the TAE slot(s) populated

## Functions

• `LstepCE1`: The least biologically precautionary effort-based MP.

• `LstepCE2`: Step size is increased to 0.1

## Required Data

See Data for information on the `Data` object

`LstepCE1`: LHYear, ML, MPeff, Year

## Rendered Equations

See Online Documentation for correctly rendered equations

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

 ```1 2``` ```LstepCE1(1, Data=DLMtool::SimulatedData, plot=TRUE) LstepCE2(1, Data=DLMtool::SimulatedData, plot=TRUE) ```