srCobWeb: Plots typical fisheries stock-recruitment models with...

In droglenc/FSAsim: Simulate Data for Fisheries Stock Assessment Methods

Description

Plots typical fisheries stock-recruitment models with cobwebbing traces for four parameterizations of the Beverton-Holt and three parameterizations of the Ricker stock-recruit models.

Usage

srCobWeb(
  type = c("BevertonHolt", "Ricker"),
  param = 1,
  N = 100,
  initS = 50,
  N2ignore = 0,
  ...
)

Arguments

type	A single string that indicates which stock-recruitment model to use. See srModels in FSA.
param	A single numeric that indicates which parameterization of the type to use. See srModels in FSA.
N	A single numeric that indicates the number of iterations to run for the cobwebbing.
initS	A single numeric that indicates the starting value of spawning stock size.
N2ignore	A single numeric that indicates the number of initial iterattions to ignore when plotting the results. This allows the function to ‘burn-in’ before showing results.
...	Optional parameters that are used in stock-recruitment model indicated with type and param. See srModels and srFuns in FSA for the list and meanings of the parameters. Also see the examples..

Details

This function can be used to explore the dynamics of stock-recruitment models for various parameter choices.

The type= argument is used to choose either the "BevertonHolt" or "Ricker" models. Different parameterizations of these two models are chosen with the param= argument. Four paramaterizations of the Beverton-Holt model and three parameterizations of the Ricker model are allowed. See srModels and srFuns in FSA for a representation of each parameterization.

Value

None. However a two-paned graphic is printed. The top pane represents the stock-recruit function as a blue line and the 1:1 replacement line as a red line. In addition, the ‘cob-webbing’ procedure is shown by a gray line. The gray line of the cobwebbing will become ‘darker’ as more cobwebbing lines are plotted on top of each other. This makes it easer to see periodicity if it exists. The ‘stopping’ point in the cobwebbing is shown as a red dot and the ‘starting’ point is shown, as long as N2Ignore=0, a green dot. The bottom panel is the stock size plotted against time.

Author(s)

Derek H. Ogle, [e-mail]

See Also

srSim; srModels and srFuns in FSA.

Examples

# First parametrization of the Ricker model
#   exhibiting various dynamics
srCobWeb(type="Ricker",param=1,a=5,b=0.01)
srCobWeb(type="Ricker",param=1,a=7,b=0.01)
srCobWeb(type="Ricker",param=1,a=10,b=0.01)
srCobWeb(type="Ricker",param=1,a=13,b=0.01)
srCobWeb(type="Ricker",param=1,a=14.5,b=0.01)
srCobWeb(type="Ricker",param=1,a=15,b=0.01)
srCobWeb(type="Ricker",param=1,a=16,b=0.01)
srCobWeb(type="Ricker",param=1,a=17,b=0.01)

# demonstration N2ignore
srCobWeb(type="Ricker",param=1,a=13,b=0.01,N2ignore=30)

# Third parametrization of the Ricker model
srCobWeb(type="Ricker",param=3,a=13,Rp=300)

# First parametrization of the Beverton-Holt model
srCobWeb(type="BevertonHolt",param=1,a=20,b=0.01)

droglenc/FSAsim documentation built on Feb. 15, 2020, 11:20 p.m.