EtargetLopt {DLMtool}R Documentation

Effort Target Optimum Length

Description

This MP adjusts effort limit based on the ratio of recent mean length (over last yrsmth years) and a target length defined as L_{\textrm{opt}}. Effort MP: adjust effort up/down if mean length above/below Ltarget

Usage

EtargetLopt(x, Data, reps = 100, plot = FALSE, yrsmth = 3, buffer = 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

Number of years to calculate average length

buffer

Parameter controlling the fraction of calculated effor - acts as a precautionary buffer

Details

The TAE is calculated as:

\textrm{TAE}_y = \textrm{TAE}_{y-1} ≤ft((1-\textrm{buffer}) (w + (1-w)r) \right)

where \textrm{buffer} is specified in argument buffer, w is fixed at 0.5, and:

r = \frac{L_{\textrm{recent}}}{L_{\textrm{opt}}}

where L_{\textrm{recent}}is mean length over last yrmsth years, and:

L_{\textrm{opt}} = \frac{L_∞ W_b}{\frac{M}{K} + W_b }

where L_∞ is von Bertalanffy asymptotic length, W_b is exponent of the length-weight relationship, M is natural mortality, and K is von Bertalanffy growth coefficient.#'

Value

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

Required Data

See Data-class for information on the Data object

EtargetLopt: ML, MPeff, Mort, vbK, vbLinf, wlb

Rendered Equations

See Online Documentation for correctly rendered equations

Author(s)

HF Geromont

Examples

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

[Package DLMtool version 6.0.2 Index]