Ecotypes

In ypr: Yield Per Recruit

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  fig.width = 4
)

Ecotypes

In the ypr package a population is considered to be group of interbreeding fish that are indistinguishable to anglers. Ecotypes are groups of individuals with a population that have different life-history strategies. Consequently, ecotypes must share key fishery (pi, Llo, Lup, Nc, rho, Hm and q) and stock recruitment (BH, RK, tR and Rmax) parameters.y To use a yield-per-recruit approach it is also necessary to assume that the relative proportion of recruits (RPR) adopting each life-history strategy is independent of the size and composition of the parental stock.

Two Ecotypes

Consider a population with a smaller ecotype and a second larger ecotype that delays maturation in order to achieve sufficient size to switch to piscivory which allows it to grow much larger.

library(ypr)
library(ggplot2) # for plotting

ecotypes <- ypr_ecotypes(
  Linf2 = 200,
  L2 = c(100, 50),
  Ls = c(50, 75), 
  pi = 0.05,
  names = c("small", "large"),
  RPR = c(0.8, 0.2))

ypr_plot_schedule(ecotypes) + scale_color_manual(values = c("black", "blue"))
ypr_plot_schedule(ecotypes, x = "Age", y  = "Spawning") + scale_color_manual(values = c("black", "blue"))

Fish

ypr_plot_fish(ecotypes, color = "white") + scale_fill_manual(values = c("black", "blue"))
ypr_plot_fish(ecotypes, x = "Length", y = "Caught", color = "white", binwidth = 15) + scale_fill_manual(values = c("black", "blue"))

Stock-Recruitment

ypr_plot_sr(ecotypes, biomass = TRUE)
ypr_tabulate_sr(ecotypes, biomass = TRUE)

Yield

ypr_tabulate_yield(ecotypes, biomass = TRUE)
ypr_plot_yield(ecotypes, biomass = TRUE)

ypr documentation built on Aug. 30, 2022, 1:11 a.m.