| 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} \left((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_\infty W_b}{\frac{M}{K} + W_b }
where L_\infty 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, Year, vbK, vbLinf, wlb
Rendered Equations
See Online Documentation for correctly rendered equations
Author(s)
HF Geromont
Examples
EtargetLopt(1, MSEtool::SimulatedData, plot=TRUE)