Ltarget1 {DLMtool}R Documentation

Length Target TAC MP


A management procedure that incrementally adjusts the TAC to reach a target mean length in catches.


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)



A position in the data object


A data object


The number of stochastic samples of the MP recommendation(s)


Logical. Show the plot?


Years over which to calculate mean length.


Parameter controlling the fraction of mean catch to start using in first year


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]


\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 (pre-projection), 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 (pre-projection years) (L_\textrm{ave}), and L_\textrm{target} is (except for L95target) xL L_\textrm{ave}.


An object of class Rec-class with the TAC slot populated with a numeric vector of length reps


Required Data

See Data-class 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

Rendered Equations

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. doi:10.1093/icesjms/fst232

See Also

Other Length target MPs: Lratio_BHI(), LtargetE1()


Ltarget1(1, Data=MSEtool::SimulatedData, plot=TRUE)
Ltarget2(1, Data=MSEtool::SimulatedData, plot=TRUE)
Ltarget3(1, Data=MSEtool::SimulatedData, plot=TRUE)
Ltarget4(1, Data=MSEtool::SimulatedData, plot=TRUE)
L95target(1, Data=MSEtool::SimulatedData, plot=TRUE)

[Package DLMtool version 6.0.2 Index]