growtrans: Growth Transition Matrix for a Size-Structured Population...

In fishmethods: Fishery Science Methods and Models

Growth Transition Matrix for a Size-Structured Population Dynamics Model

Description

Generates a growth transition matrix from parameters of the von Bertalanffy growth equation following Chen et al. (2003)

Usage

growtrans(Lmin = NULL, Lmax = NULL, Linc = NULL, Linf = NULL, SELinf = NULL,
          K = NULL, SEK = NULL, rhoLinfK = NULL)

Arguments

Lmin	Mid-point of starting size class.
Lmax	Mid-point of end size class. This should be one increment larger than Linf.
Linc	Size class increment.
Linf	L-infinity parameter of the von Bertalanffy growth equation.
SELinf	Standard error of Linf.
K	Growth parameter of the von Bertalanffy growth equation.
SEK	Standard error of K.
rhoLinfK	Correlation between Linf and K. Usually from a parameter correlation matrix.

Details

Transition probabilities are calculated by using formulae 3-9 and procedures in Chen et al. (2003). Negative growth increments result if Lmax is beyond Linf, so the transition matrix is truncated at Linf. The last size class acts as a plus group and has a probability of 1.

Value

A matrix of dimensions n size classes x n size classes.

Note

This function is based on an example EXCEL spreadsheet provided by Yong Chen.

Author(s)

Gary A. Nelson, Massachusetts Division of Marine Fisheries [e-mail]

References

Chen, Y., M. Hunter, R. Vadas, and B. Beal. 2003. Developing a growth-transition matrix for stock assessment of the green sea urchin (Strongylocentrotus droebachiensis) off Maine. Fish. Bull. 101: 737-744.

Examples

# For Chen et al. 2003
growtrans(Lmin=40,Lmax=101,Linc=1,Linf=100,SELinf=15,K=0.100588,SEK=0.04255,rhoLinfK=0.94)

fishmethods documentation built on April 4, 2025, 1:47 a.m.