Computes CPUE-based Indicators of changes in Stock Abundance

This function computes four abundance indicators from one CPUE or biomass index of abundance: the index itself, an average over a number of years, a weighted mean over those same years and the slope of the trend over the same period.

Usage

cpue.ind(stk, idx, index = 1, nyears = 5, args, tracking)

Arguments

stk: An object representing the stock returned by the oem modules, FLStock.
idx: An FLIndices containing the indices rturned by the oem module.
index: An integer or character, specifying the index to use from idx. Default is 1.
nyears: An integer, the number of years to consider for the calculations. Default is 5.
args: A list containing dimensionality arguments, passed on by mp().
tracking: An FLQuant used for tracking indicators, intermediate values, and decisions during MP evaluation.

Value

A list containing 'stk', the input FLStock, 'ind, an FLQuants object containing the computed index metrics, and the 'tracking' table.

Details

The weighted average returned in the 'wmean' element is calculated over the last nyears. The last year's weight is set as 50%, and the remaining years share the other 50% proportionally. The 'slope' metric is computed on the log-transformed data.

Three elements are added to the tracking table:

mean.ind, with the index average
wmean.ind, with the index weighted average
slope.ind, with the index slope

Examples

data(plesim)
# MP control with CPUE: catch ~ weighted 4-year mean CPUE
ctrl <- mpCtrl(est=mseCtrl(method=cpue.ind, args=list(index=2)),
  hcr=mseCtrl(method=hockeystick.hcr, args=list(metric="wmean",
  trigger=2000, output="catch", target=1.25e5)))

# Run the MP
 run <- mp(om, oem, control=ctrl, args=list(iy=2025, fy=2035))
#> 2025  - 2026  - 2027  - 2028  - 2029  - 2030  - 2031  - 2032  - 2033  - 2034  - 

# Plot results
plot(om, run)