Description Usage Arguments Details Value Functions Required Data Rendered Equations Author(s) References See Also Examples
A management procedure that incrementally adjusts the TAC to reach a target mean length in catches.
1 2 3 4 5 6 7 8 9 10 11 12 13 14  Ltarget1(x, Data, reps = 100, plot = FALSE, yrsmth = 5, xx = 0,
xL = 1.05)
Ltarget2(x, Data, reps = 100, plot = FALSE, yrsmth = 5, xx = 0,
xL = 1.1)
Ltarget3(x, Data, reps = 100, plot = FALSE, yrsmth = 5, xx = 0,
xL = 1.15)
Ltarget4(x, Data, reps = 100, plot = FALSE, yrsmth = 5, xx = 0.2,
xL = 1.15)
L95target(x, Data, reps = 100, plot = FALSE, yrsmth = 5, xx = 0,
xL = 1.05)

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 mean length. 
xx 
Parameter controlling the fraction of mean catch to start using in first year 
xL 
Parameter controlling the magnitude of the target mean length of catches relative to average length in catches. 
Four target length MPs proposed by Geromont and Butterworth 2014. Tested by Carruthers et al. 2015.
The TAC is calculated as:
If L_\textrm{recent} ≥q L_0:
\textrm{TAC} = 0.5 \textrm{TAC}^* ≤ft[1+≤ft(\frac{L_\textrm{recent}L_0}{L_\textrm{target}L_0}\right)\right]
else:
\textrm{TAC} = 0.5 \textrm{TAC}^* ≤ft[\frac{L_\textrm{recent}}{L_0}^2\right]
where \textrm{TAC}^* is (1  xx
) mean catches from the last yrsmth
historical years (preprojection),
L_\textrm{recent} is mean length in last yrmsth
years, L_0 is (except for L95target
) 0.9 average catch in the last
2 x yrsmth
historical (preprojection years) (L_\textrm{ave}), and L_\textrm{target} is
(except for L95target
) xL
L_\textrm{ave}.
An object of class Rec
with the TAC
slot populated with a numeric vector of length reps
Ltarget1
: The least biologically precautionary TACbased MP.
Ltarget2
: Increasingly biologically precautionary (xL
= 1.1).
Ltarget3
: Increasingly biologically precautionary (xL
= 1.1).
Ltarget4
: The most biologically precautionary TACbased MP (xL
= 1.1, xx
=0.2).
L95target
: Same as Ltarget1 but here the target and limit
mean lengths are based on the length at maturity distribution rather
than an arbitrary multiplicative of the mean length
See Data for information on the Data
object
Ltarget1
: Cat, LHYear, ML, Year
Ltarget2
: Cat, LHYear, ML, Year
Ltarget3
: Cat, LHYear, ML, Year
Ltarget4
: Cat, LHYear, ML, Year
L95target
: Cat, L50, LHYear, ML, 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, 464482.
Geromont, H.F., Butterworth, D.S. 2014. Generic management procedures for datapoor fisheries; forecasting with few data. ICES J. Mar. Sci. doi:10.1093/icesjms/fst232
Other Length target MPs: Lratio_BHI
,
LtargetE1
1 2 3 4 5  Ltarget1(1, Data=DLMtool::SimulatedData, plot=TRUE)
Ltarget2(1, Data=DLMtool::SimulatedData, plot=TRUE)
Ltarget3(1, Data=DLMtool::SimulatedData, plot=TRUE)
Ltarget4(1, Data=DLMtool::SimulatedData, plot=TRUE)
L95target(1, Data=DLMtool::SimulatedData, plot=TRUE)

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