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Estimate angler effort from camera/time-lapse count data

Source: R/est-effort-camera.R
est_effort_camera.Rd

Estimates total angler-hours from a camera-based creel survey design. Two estimation modes are supported:

Usage

est_effort_camera(
  design,
  interviews = NULL,
  effort_col = "hours_fished",
  intercept_col = NULL,
  h_open = NULL,
  variance = c("taylor", "replicate"),
  conf_level = 0.95
)

Arguments

design

A creel_design object created with creel_design(..., survey_type = "camera") and counts attached via add_counts().

interviews

Optional data frame of angler interview records for ratio calibration. Must contain the columns named by strata_col (matching design$strata_cols[1]) and effort_col. When NULL, falls back to raw count expansion and h_open is required.

effort_col

Character scalar. Column in interviews containing per-trip effort in hours. Default "hours_fished".

intercept_col

Character scalar or NULL. Column in the count data representing the camera count during the interview interception period. Default NULL (auto-detects the first numeric count column).

h_open

Numeric scalar. Fishable hours per day. Required when interviews = NULL. Default NULL.

variance

Character. Variance method: "taylor" (default) or "replicate".

conf_level

Numeric confidence level. Default 0.95.

Value

A creel_estimates object with columns estimate, se, se_between, se_within, ci_lower, ci_upper, n.

Details

  • Ratio calibration (recommended, when interview data are available): Per-stratum calibration ratios (mean interview effort / mean camera count during the interview period) scale raw camera counts to angler-hours. Variance is estimated via Taylor linearisation or replicate weights.

  • Raw count expansion (fallback): Camera ingress counts are multiplied by h_open (fishable hours per day). Use when no interview data are available.

References

Hartill, B.W., Cryer, M., and Morrison, M.A. 2020. Camera-based creel surveys: estimating fishing effort and catch rates from ingress-egress camera counts. Fisheries Research 231:105706. doi:10.1016/j.fishres.2020.105706

See also

Other "Survey Design": add_catch(), add_counts(), add_interviews(), add_lengths(), add_sections(), as_hybrid_svydesign(), as_survey_design(), compute_angler_effort(), compute_effort(), creel_design(), creel_schema(), prep_counts_boat_party(), prep_counts_daily_effort(), prep_interview_catch(), prep_interviews_trips(), validate_creel_schema()

Examples

if (FALSE) { # \dontrun{
library(tidycreel)
data(example_camera_counts)
data(example_camera_interviews)

cal <- data.frame(
  date     = unique(example_camera_counts$date),
  day_type = unique(example_camera_counts[, c("date", "day_type")])[["day_type"]]
)
design <- creel_design(cal,
  date = date, strata = day_type,
  survey_type = "camera", camera_mode = "counter"
)

# Filter to operational rows
ops <- example_camera_counts[
  example_camera_counts$camera_status == "operational",
]
design <- add_counts(design, ops)

# Ratio calibration using interview hours
est <- est_effort_camera(design, interviews = example_camera_interviews)
print(est)
} # }