A simple harvest control rule that sets total catch to a fixed target value regardless of stock status or other indicators.
Arguments
- stk
The 'oem' observation or SA estimation, an FLStock object.
- ctrg
The target catch value, numeric or FLQuant. If numeric, the value is replicated across all iterations and management years.
- args
A list containing dimensionality arguments, passed on by mp(). Must include elements: ay (advice year), it (number of iterations), mys (management years vector).
- tracking
An FLQuant used for tracking indicators, intermediate values, and decisions during MP evaluation.
Details
This HCR implements a constant catch strategy where the target catch is directly applied. The function is useful for testing fixed harvest strategies or as a baseline reference in MSE comparisons. The target catch can be specified as either a single numeric value (applied across all iterations and years) or as an FLQuant object with possible year and iteration structure.
Examples
# Example dataset
data(plesim)
# Sets up an mpCtrl for fixed catch at MSY level
ctrl <- mpCtrl(est = mseCtrl(method=perfect.sa),
hcr = mseCtrl(method=fixedC.hcr, args=list(ctrg=1500)))
# Runs mp between 2021 and 2035
run <- mp(om, control=ctrl, args=list(iy=2021, fy=2035))
#> 2021 - 2022 - 2023 - 2024 - 2025 - 2026 - 2027 - 2028 - 2029 - 2030 - 2031 - 2032 - 2033 - 2034 -
# Plot results
plot(om, run)
# Check output
catch(run)
#> An object of class "FLQuant"
#> iters: 100
#>
#> , , unit = unique, season = all, area = unique
#>
#> year
#> age 2020 2021 2022
#> all 1.14e+03(2.62e+02) 1.15e+03(2.78e+02) 1.09e+04(3.13e+03)
#> year
#> age 2023 2024 2025
#> all 4.49e+02(1.26e+02) 1.68e+00(7.97e-01) 4.84e-06(4.39e-07)
#> year
#> age 2026 2027 2028
#> all 4.89e-06(4.72e-07) 4.97e-06(5.06e-07) 4.85e-06(3.84e-07)
#> year
#> age 2029 2030 2031
#> all 4.84e-06(3.33e-07) 4.89e-06(5.14e-07) 4.81e-06(4.47e-07)
#> year
#> age 2032 2033 2034
#> all 4.89e-06(5.01e-07) 4.91e-06(4.37e-07) 4.84e-06(4.33e-07)
#> year
#> age 2035
#> all 4.93e-06(4.94e-07)
#>
#> units: t
# Using FLQuant for time-varying catch
ctrg_var <- FLQuant(seq(1000, 2000, length=10), dimnames=list(year=2021:2030))
ctrl2 <- mpCtrl(est = mseCtrl(method=perfect.sa),
hcr = mseCtrl(method=fixedC.hcr, args=list(ctrg=ctrg_var)))
# Example using function directly
fixedC.hcr(stock(om), ctrg=1500, args=list(ay=2017, it=100,
mys=2018:2020), tracking=FLQuant())
#> $ctrl
#> An object of class "fwdControl"
#> (step) year quant min value max
#> 1 2018 fbar NA 1500.000 NA
#> 2 2019 fbar NA 1500.000 NA
#> 3 2020 fbar NA 1500.000 NA
#> iters: 100
#>
#>
#> $tracking
#> An object of class "FLQuant"
#> , , unit = unique, season = all, area = unique
#>
#> year
#> quant 1
#> all NA
#>
#> units: NA
#>