ICI {DLMtool} | R Documentation |
The MP adjusts catch based on the value of the index in the current year relative to the time series mean and standard error.
ICI(x, Data, reps = 100, plot = FALSE) ICI2(x, Data, reps = 100, plot = FALSE)
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? |
The TAC is calculated as:
\textrm{TAC}_y=C_{y-1} α
where C_{y-1} is the catch from the previous year, and α is defined as:
where I is the index in the most recent year, d is 0.75 for ICI
and ICI2
,
u is 1.05 and 1.25 forICI
and ICI2
respectively, and \textrm{CI}_L
and \textrm{CI}_L are the lower and upper bound of the confidence
interval of mean historical index. The confidence interval is
calculated using Z-scores described in the Functions section below.
An object of class Rec-class
with the TAC
slot populated with a numeric vector of length reps
ICI
: The catch is reduced by 0.75 if the Z-score of the current year's index is less than -0.44.
The catch is increased by 1.05 if the Z-score of the current year's index is greater than 1.96. Otherwise, the catch is held constant.
ICI2
: This method is less precautionary of the two ICI MPs by allowing for a
larger increase in TAC and a lower threshold of the index to decrease the TAC. The catch is reduced by 0.75
if the Z-score of the current year's index is less than -1.96. The catch is increased by 1.25
if the Z-score of the current year's index is greater than 1.96. Otherwise, the catch is held constant.
See Data-class
for information on the Data
object
ICI
: Cat, Ind
ICI2
: Cat, Ind
See Online Documentation for correctly rendered equations
Coded by Q. Huynh. Developed by Jardim et al. (2015)
Ernesto Jardim, Manuela Azevedo, Nuno M. Brites, Harvest control rules for data limited stocks using length-based reference points and survey biomass indices, Fisheries Research, Volume 171, November 2015, Pages 12-19, ISSN 0165-7836, https://doi.org/10.1016/j.fishres.2014.11.013
Other Index methods:
GB_slope()
,
GB_target()
,
Gcontrol()
,
Iratio()
,
Islope1()
,
Itarget1_MPA()
,
Itarget1()
,
ItargetE1()
ICI(1, Data=MSEtool::Atlantic_mackerel, plot=TRUE) ICI2(1, Data=MSEtool::Atlantic_mackerel, plot=TRUE)