vbComp: Evaluates and plots the traditional von Bertalanffy growth...
In droglenc/FSAsim: Simulate Data for Fisheries Stock Assessment Methods

Description Usage Arguments Details Value Author(s) See Also Examples

Evaluates and plots the traditional von Bertalanffy growth model for several parameter choices. Typical use will be for comparing the shape of the model among parameter estimates for multiple species.

1	vbComp(df, ages = 20, ...)

`df`	A data.frame with rows of different parameter choices. See details.
`ages`	A numeric or vector of the maximum age over which to evaluate the models. See details.
`...`	Additional arguments to pass to `plot`.

The data frame, df, must have a column that contains the species name and columns for the Linf, K, and to parameters (with the columns having those names). Each row contains values for a seperate model evaluation. Typical exercises will select rows from the data(VBGMlit) data frame.

All evaluations will be over ages that begin at zero and continue to the value or values provided in ages. If ages has a length of 1 then all evaluations will extend from zero to this age. However, if ages is a vector of the same length as the number of rows in df then the extent of the evaluations for each row in df will be from 0 to the corresponding value in ages. Thus, ages can be used to provide model evaluations over different ages.

None. However a plot of the hypothetical lengths-at-age for each species shown in the rows of df is produced.

Derek H. Ogle, dogle@northland.edu

VBGMlit.

# load VBGMlit data frame
data(VBGMlit)
# select three example species from VBGMlit
v <- VBGMlit[c(1,7,57),]
# default behavior for three example species
vbComp(v)
# same three species but with varying maximum ages
vbComp(v,ages=c(10,20,25))