Length-Based SPR MPs

The spawning potential ratio (SPR) is estimated using the LBSPR method and compared to a target of 0.4.

LBSPR(
  x,
  Data,
  reps = 1,
  plot = FALSE,
  SPRtarg = 0.4,
  theta1 = 0.3,
  theta2 = 0.05,
  maxchange = 0.3,
  n = 5,
  smoother = TRUE,
  R = 0.2
)

LBSPR_MLL(
  x,
  Data,
  reps = 1,
  plot = FALSE,
  SPRtarg = 0.4,
  n = 5,
  smoother = TRUE,
  R = 0.2
)

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?
SPRtarg

The target SPR
theta1

Control parameter for the harvest control rule
theta2

Control parameter for the harvest control rule
maxchange

Maximum change in effort
n

Last number of years to run the model on.
smoother

Logical. Should the SPR estimates be smoothed?
R

variance of sampling noise for smoother

Value

An object of class Rec with the TAE slot populated

Details

Effort is modified according to the harvest control rules described in Hordyk et al. (2015b):

Functions

  • LBSPR_MLL: Fishing retention-at-length is set equivalent to slightly higher than the maturity curve if SPR < 0.4

Required Data

See Data for information on the Data object

LBSPR: CAL, CAL_bins, L50, L95, LHYear, Mort, vbK, vbLinf, wlb, Year

Rendered Equations

See Online Documentation for correctly rendered equations

References

Hordyk, A., Ono, K., Valencia, S., Loneragan, N., and Prince J (2015a). A novel length-based empirical estimation method of spawning potential ratio (SPR), and tests of its performance, for small-scale, data-poor fisheries, ICES Journal of Marine Science, 72 (1), 217-231

Hordyk, A. R., Loneragan, N. R., & Prince, J. D. (2015b). An evaluation of an iterative harvest strategy for data-poor fisheries using the length-based spawning potential ratio assessment methodology. Fisheries Research, 171, 20-32. https://doi.org/10.1016/j.fishres.2014.12.018

Examples

LBSPR(1, Data=DLMtool::SimulatedData, plot=TRUE)
#>   Effort 
#> 0.959735 
LBSPR_MLL(1, Data=DLMtool::SimulatedData, plot=FALSE)
#>      LR5      LFR 
#> 83.89029 88.30557