Itarget1 {DLMtool} | R Documentation |
A management procedure that incrementally adjusts the TAC (starting from reference level that is a fraction of mean recent catches) to reach a target CPUE / relative abundance index
Itarget1(x, Data, reps = 100, plot = FALSE, yrsmth = 5, xx = 0, Imulti = 1.5) Itarget2(x, Data, reps = 100, plot = FALSE, yrsmth = 5, xx = 0, Imulti = 2) Itarget3(x, Data, reps = 100, plot = FALSE, yrsmth = 5, xx = 0, Imulti = 2.5) Itarget4(x, Data, reps = 100, plot = FALSE, yrsmth = 5, xx = 0.3, Imulti = 2.5)
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 the average index is calculated. |
xx |
Parameter controlling the fraction of mean catch to start using in first year |
Imulti |
Parameter controlling how much larger target CPUE / index is compared with recent levels. |
Four index/CPUE target MPs proposed by Geromont and Butterworth 2014. Tested by Carruthers et al. 2015.
The TAC is calculated as: If I_\textrm{recent} ≥q I_0:
\textrm{TAC}= 0.5 \textrm{TAC}^* ≤ft[1+≤ft(\frac{I_\textrm{recent} - I_0}{I_\textrm{target} - I_0}\right)\right]
else:
\textrm{TAC}= 0.5 \textrm{TAC}^* ≤ft[\frac{I_\textrm{recent}}{I_0}^2\right]
where I_0 is 0.8 I_{\textrm{ave}} (the average index over the 2 x yrsmth
years prior to the projection period),
I_\textrm{recent} is the average index over the past yrsmth
years, and
I_\textrm{target} is Imulti
times I_{\textrm{ave}},
and \textrm{TAC}^* is:
(1-x)C
where x is argument xx
and C is the average catch over the last 5 years of the historical period.
An object of class Rec-class
with the TAC
slot populated with a numeric vector of length reps
Itarget1
: The less precautionary TAC-based MP
Itarget2
: Increasing biologically precautionary TAC-based MP
Itarget3
: Increasing biologically precautionary TAC-based MP
Itarget4
: The most biologically precautionary TAC-based MP
See Data-class
for information on the Data
object
Itarget1
: Cat, Ind, LHYear, Year
See Online Documentation for correctly rendered equations
T. Carruthers
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. 72, 251-261. doi:10.1093/icesjms/fst232
Other Index methods:
GB_slope()
,
GB_target()
,
Gcontrol()
,
ICI()
,
Iratio()
,
Islope1()
,
Itarget1_MPA()
,
ItargetE1()
Itarget1(1, MSEtool::Atlantic_mackerel, plot=TRUE) Itarget2(1, MSEtool::Atlantic_mackerel, plot=TRUE) Itarget3(1, MSEtool::Atlantic_mackerel, plot=TRUE) Itarget4(1, MSEtool::Atlantic_mackerel, plot=TRUE)