Define a constant-catch harvest control rule

`def.hcr.conscat()` defines a simple harvest control rule (HCR) that recommends a constant catch (TAC) over time. The baseline TAC can be supplied directly via `constantC` or estimated from recent catches, and optional reduction rules can be used to step down the TAC when performance is poor (e.g. low biomass or repeated assessment failure).

Usage

def.hcr.conscat(
  id = "conscat",
  constantC = NULL,
  clyears = 1,
  red = NA,
  redyears = 2,
  redAlways = FALSE,
  assessmentInterval = 1,
  ffmsySD = 0,
  bbtriggerSD = 0,
  rightRef = 1,
  set. = check.set(),
  env = globalenv()
)

Arguments

id: Character string giving the identifier for this HCR (for example `"conscat"`). This label is used when selecting HCRs in `set$hcr` and in summaries and plots.
constantC: Optional numeric giving the constant catch level (e.g. in tonnes). If `NULL` (default), the constant catch is derived internally from recent catches, typically using the last `clyears` years.
clyears: Integer specifying the number of historical years used to calculate the baseline catch level when `constantC` is `NULL`.
red: Optional numeric reduction factor applied to the constant catch (e.g. `0.8` corresponds to a 20 automatic reduction is applied and the TAC remains constant.
redyears: Integer giving the number of years over which the reduction criteria are evaluated. The exact interpretation depends on the internal implementation (e.g. how many years of poor performance trigger a reduction).
redAlways: Logical; if `TRUE`, the reduction rule is evaluated in all years where the criteria are met. If `FALSE`, the reduction may be applied only once or under more restrictive conditions, depending on the internal implementation.
assessmentInterval: Positive integer giving the interval (in years) between assessments and TAC updates. The default `1` corresponds to an annual advice cycle.
ffmsySD: Non-negative numeric giving the standard deviation of the (log) assessment error in $F/F_{MSY}$ used when simulating the assessed status for this HCR.
bbtriggerSD: Non-negative numeric giving the standard deviation of the (log) assessment error in biomass-related indicators (e.g. $B/B_{trigger}$) used for this HCR.
rightRef: Integer index specifying which reference-point set should be used when evaluating this HCR (e.g. an index into `dat$ref`).
set.: An `iamse` settings list as returned by [check.set()]. This object is updated to include the newly defined HCR.
env: Environment in which the HCR function is created and stored. Defaults to [globalenv()]. In most cases the default should be used.

Value

Invisibly returns the updated `set.` object. The function is called for its side effects (defining and registering the HCR).

Details

The function is usually called for its side effects: it registers a new HCR with identifier `id` in the `iamse` settings object `set.` and, by default, also in the supplied environment `env`. The HCR can then be included in `set$hcr` and evaluated with [run.mse()].