• Same as previous version.
  • Rk is now the egg to tR survival if between 0 and 1.
  • Internal changes only.
  • House-keeping.
  • Pass yield parameters Ly, harvest and biomass to ypr_report().
  • Removed suggests dependency on checkr.

Major Features

Population Parameters

Replaced parameters

  • M (annual instantaneous natural mortality rate)
  • Mb (annual instantaneous natural mortality rate (as a function of length) scaling exponent)
  • A0 (initial post age tR density independent mortality probability)


  • n (annual natural mortality rate from age tR to length Ln)
  • nL (annual natural mortality rate from length Ln)
  • Ln (length at which the natural mortality rate switches from n to nA)


  • Added parameters k2, Linf2 and L2 to allow for biphasic growth.
  • Set Lp value to be 1000 as opposed to Linf.
  • Set Ls and Lv arguments to be 50 as opposed to Linf/2.
  • Allow L2, Ln, Ls and Lv to also take ages (as negative values).


Population Reports


  • Added plot of biomass and eggs to report.
  • Added percent = FALSE argument to ypr_plot_fish()


Bug Fixes

  • Improved handling of unsustainable populations (no longer negative fish numbers).
  • ypr_populations() now generates names
  • Fixed Quesnel Lake Trout and Rainbow Trout mix up
  • Now uses q instead of Ea and Eb for effort
  • Parameter Rk now has to be greater than >= 1
  • Added ypr_exploitation() to convert capture probabilities to exploitation probabilities.
  • Added ypr_report() to generate Rmd file for population.
  • Can now pass Rk as egg to recruit survival (at low density).
  • Set default value of Wa to be 0.01.
  • Added ypr_populations() to generate all combinations of parameters.
  • Made ypr_tabulate_sr(), ypr_tabulate_yield(), ypr_tabulate_yields(), ypr_plot_yield() generic with definitions for ypr_population and ypr_populations objects.
  • Added scaling parameter A0 for initial interval mortality of recruits.
  • Added scaling parameters Ea and Eb to allow plots of yield per effort.
  • Added Age, Length, Weight and Effort to ypr_tabulate_yield() and added ypr_tabulate_yields()
  • Added y arg to ypr_plot_yield() to allow plotting of mean age, length, weight, effort or yield per effort by exploitation or capture probability.
  • Added ypr_plot_histogram() to plot frequency distributions of catch, spawners and in lake by age, length or weight bins.
  • Added ypr_tabulate_parameters() to get table of parameters, values and descriptions and ypr_detabulate_parameters() to convert back to a population object.
  • Added ypr_tabulate_sr() to get table of eggs and recruits at unfished, actual and optimal rates.
  • Added print.ypr_population().
  • Added Mb to scale mortality by length and BH to distinguish between Beverton-Holt and Ricker curves and es for probability of a mature fish spawning and Sm for spawning mortality probability and Sp for spawning power and vulnerability power Vp and slot limit non-complicance parameter Nc and scaling parameter R0.
  • Added ypr_population_update() to update population parameters.
  • Added ypr_yield_tabulate() to tabulate actual and optimal yields.
  • Added ypr_sr() to get stock recruitment parameters and ypr_plot_sr() to plot.
  • Added ypr_inst2inter() and ypr_inter2instant() to convert mortality rates.
  • Switched nu for M and R0 for Rmax.
  • Switched yield parameters harvest and biomass to FALSE by default.
  • Renamed a to Wa and b to Wb and eta to Hm and mu to pi and Rt to tR.
  • Removed Capture (as covered by single value) and TotalMortality from schedule and added Spawning.
  • Initial Release