R/DWEFgec.R

In JVAdams/GLFC: Great Lakes Fishery Commission

#' Gear Efficiency Correction for Deepwater Electrofisher
#'
#' Use the relation between larval lamprey length and probability of catch
#' in the deepwater electrofisher to derive a gear efficiency correction factor.
#' @param llengthmm
#'   A numeric vector of lengths (in mm) of live larval lampreys.
#' @details
#'   Lake-stream IDs are combination of lake ID and stream ID
#'   e.g., 1.064 = lake ID + (stream ID)/1000.
#'
#'   For both estimate files (csvNew and csvOld), there should be no missing
#'   values in \code{year}, \code{lake}, or \code{lscode}.
#'   Both files may contain variables other than those required.
#'   Those with the same name as variables in \code{streamInfo} will be
#'   replaced.  Others will be kept.
#' @return
#'   A numeric vector equivalent to the inverse probability of capture,
#'   \code{p}, at length \code{llengthmm.},
#'   \code{logit(p) = 1.732 - 0.0229*llengthmm}.  This correction factor can
#'   then be multiplied by the number of lamprey of that size captured
#'   to estimate the catch adjusted for gear efficiency.
#' @export
#' @references
#' Robinson, JM, MJ Wilberg, JV Adams, and ML Jones. 2014.
#'  Comparing methods for estimating larval sea lamprey (\emph{Petromyzon marinus})
#'  density in the St. Marys River for the purposes of control.
#'  Journal of Great Lakes Research 40(3):739-747.
#'  \href{https://doi.org/10.1016/j.jglr.2014.05.012}{[link]}
#' @examples
#' catch <- 1:6
#' lenmm <- seq(80, 180, 20)
#' adjcatch <- catch*DWEFgec(lenmm)
#' cbind(catch, lenmm, adjcatch)
#'
DWEFgec <- function(llengthmm) {
  if(!is.numeric(llengthmm)) stop("llengthmm must be a numeric vector")
  1 + exp(0.0229 * llengthmm - 1.732)
}