Generate Key Projection Quantities and Table Plot

Computes reference points and runs a short deterministic projection to give terminal spawning biomass, catch advice and status ratios by model and region, returned as a tidy data frame and a formatted table plot.

Usage

get_key_quants(data, rep, reference_points_opt, proj_model_opt, model_names)

Arguments

data: List of length n_models, each a SPoRC data list holding the region, year, age, fleet and biological inputs.
rep: List of length n_models, each a SPoRC report list from obj$report() after optimization, holding recruitment, selectivity, fishing mortality and numbers at age.
reference_points_opt: Named list passed to Get_Reference_Points, holding SPR_x (the target spawning potential ratio, which may be NULL under type = "bh_msy"), t_spawn (the fraction of the year elapsed before spawning), sex_ratio_f (n_pop, n_regions), calc_rec_st_yr (the first model year averaged over for recruitment), rec_age, type (e.g. "multi_region") and what (e.g. "global_SPR"), and optionally calc_rec_yrs, the model years recruitment is averaged and projected from, which overrides calc_rec_st_yr and rec_age.
proj_model_opt: Named list passed to Do_Population_Projection, holding n_proj_yrs, n_avg_yrs (terminal years the demographic inputs are averaged over before being kept constant across the projection), HCR_function with signature function(x, frp, brp, ...), recruitment_opt ("mean_rec", "bh_rec", "zero_rec" or "inv_gauss"), and fmort_opt ("HCR" to apply the control rule to each region's SSB, "HCR_global" to apply it to SSB summed across regions as global reference points need, or "Input" to fish at the F reference point every year without the control rule).
model_names: Character vector of length n_models of display names.

Value

A list of two. The first is a data frame of key quantities by model and region with columns Model, Region, Terminal_SSB, Terminal_SSB0, Terminal_F, Catch_Advice, B_Ref_Pt, F_Ref_Pt, B_over_B_Ref, B_over_DynB_Ref and F_over_F_Ref. The second is a cowplot ggdraw object rendering the same quantities as a table.

Details

Each model has its reference points computed, its demographic inputs averaged over the last n_avg_yrs years, the population projected forward n_proj_yrs years, and terminal SSB, dynamic unfished SSB, catch advice (year 2 of the projection) and the status ratios extracted.

Under recruitment_opt = "bh_rec" the stock-recruit parameters reach the projection through an internal srr_opt list built from year-1 demographics to approximate unfished SSB. Under "inv_gauss" a warning is issued, since only one deterministic simulation is run and stochastic recruitment belongs in a full MSE loop.

Note

These quantities are approximate and are not catch advice. This is a simplified projection interface for rapid model comparison and diagnostic screening; stochastic recruitment, closed-loop feedback and fleet-specific control rules need Do_Population_Projection directly.

Examples

if (FALSE) { # \dontrun{
  reference_points_opt <- list(
    SPR_x          = 0.4,
    t_spawn        = 0,
    sex_ratio_f    = array(0.5, dim = c(n_pop, n_regions)),
    calc_rec_st_yr = 20,
    rec_age        = 2,
    type           = "multi_region",
    what           = "global_SPR"
  )

  proj_model_opt <- list(
    n_proj_yrs      = 2,
    n_avg_yrs       = 1,
    HCR_function    = function(x, frp, brp, alpha = 0.05) {
      stock_status <- x / brp
      if (stock_status >= 1)                            frp
      else if (stock_status > alpha) frp * (stock_status - alpha) / (1 - alpha)
      else                                              0
    },
    recruitment_opt = "mean_rec",
    fmort_opt       = "HCR_global"
  )

  out <- get_key_quants(
    data                  = list(mlt_rg_sable_data),
    rep                   = list(mlt_rg_sable_rep),
    reference_points_opt  = reference_points_opt,
    proj_model_opt        = proj_model_opt,
    model_names           = "Model 1"
  )

  out[[1]]  # key quantities data frame
  out[[2]]  # table plot
} # }