growthModelSim {FSATeach}  R Documentation 
Plots hypothetical sizeatage for one of seven possible parameterizations of the von Bertalanffy, three possible parameterizations of the Gompertz, and the Schnute growth models. Slider bars are used to dynamically alter the parameters of each model.
growthModelSim(type = c("vbTypical", "vbOriginal", "vbGalucciQuinn", "vbMooij", "vbSchnute", "vbTypicalW", "vbOriginalW", "Gompertz1", "Gompertz2", "Gompertz3", "Schnute"), x = NULL, y = NULL, data = NULL, max.len = 500, max.wt = 500)
type 
A single character string identifying which growth model to use. See details. 
x 
An optional vector containing observed ages or a formula. See details. 
y 
An optional vector containing observed lengths. See details. 
data 
A data frame from which the variables in the formula should be drawn. 
max.len 
A single numeric indicating the maximum length to use in the simulations. 
max.wt 
A single numeric indicating the maximum
weight to use in the simulations (only used of

This function can be used to explore the “shape”
of the growth models for various choices of the
parameters. In this usage the x
and y
arguments should be (left) set at NULL
. This
function can also be used to visually “fit” a
growth model to a set of observed lengths and ages. This
usage may be used to provide reasonable starting values
for the parameters when fitting the growth model to the
data with nonlinear leastsquares. The observed data
are plotted by including a formula of the form
length~age
in x
and a data frame from which
to draw the variables in the formula in the data
arguments.
The type
argument is used to choose a type of
growth model and must be one of the following (the models
can be seen with growthModels
and
vbModels
):
"vbTypical"  The "typical" BevertonHolt parameterized von Bertalanffy model. 
"vbOriginal"  The original parameterization from von Bertalanffy. 
"vbMooij"  The Mooij et al (1999) paramaterization of the von Bertalanffy model. 
"vbGalucciQuinn"  The Galucci & Quinn (1979) parameterization of the von Bertalanffy model. 
"vbSchnute"  The Schnutelike paramaterization of the von Bertalanffy model. 
"vbTypicalW"  The "typical" BevertonHolt parameterized von Bertalanffy model, but for weights rather than lengths (thus, includes one more parameter). 
"vbOriginalW"  The original parameterization from von Bertalanffy, but for weights rather than lengths (thus, includes one more parameter). 
"Gompertz1"  The "first" parameterization of the Gompertz model. 
"Gompertz2"  The "second" parameterization of the Gompertz model. 
"Gompertz3"  The "third" parameterization of the Gompertz model. 
"schnute"  The Schnute(1981) fourparameter general growth model. 
None. However a dynamic graphic connected to slider bar controls in which the user can change the maximum age over which the growth model is evaluated and change the parameters specific to the chosen growth model.
Francis, R.I.C.C. 1988. Are growth parameters estimated from tagging and agelength data comparable? Canadian Journal of Fisheries and Aquatic Sciences, 45:936942.
Galucci, V.F. and T.J. Quinn II. 1979. Reparameterizing, fitting, and testing a simple growth model. Transactions of the American Fisheries Society, 108:1425.
Mooij, W.M., J.M. Van Rooij, and S. Wijnhoven. 1999. Analysis and comparison of fish growth from small samples of lengthatage data: Detection of sequal dimorphism in Eurasian perch as an example. Transactions of the American Fisheries Society 128:483490.
Schnute, J. 1981. A versatile growth model with statistically stable parameters. Canadian Journal of Fisheries & Aquatic Sciences, 38:11281140.
Schnute, J. and D. Fournier. 1980. A new approach to lengthfrequency analysis: Growth structure. Canadian Journal of Fisheries and Aquatic Sciences, 37:13371351.
growthModels
, vbModels
, and
vbStarts
.
if (interactive()) { # Explore growth models (no data)  use the defaults growthModelSim() # Schnute parameterization of the von Bertalanffy model growthModelSim(type="vbSchnute") ## Explore growth models superimposed on lengthatage data # get Smallmouth Bass data from FSA package library(FSA) data(SMBassWB) # interactively "fit" the second paramaterization of the Gompertz model to the data growthModelSim(type="Gompertz2",lencap~agecap,data=SMBassWB,max.len=500) } # end if interactive