Convert stock recruit parameters from steepness parameterization to alpha/beta (and vice versa)
Usage
hconv(alpha, phi0, SR = 1, type = 1)
R0conv(alpha, beta, phi0, SR = 1, type = 1)
SRalphaconv(h, phi0, SR = 1, type = 1)
SRbetaconv(h, R0, phi0, SR = 1, type = 1)
Arguments
- alpha
Alpha parameter
- phi0
Unfished spawners per recruit
- SR
Stock-recruit function: (1) Beverton-Holt, or (2) Ricker
- type
The parameterization of the Beverton-Holt function with respect to alpha
and beta. See details.
- beta
Beta parameter
- h
Steepness parameter
- R0
Unfished recruitment parameter
Details
The Type 1 Beverton-Holt equation is
$$R = \alpha S/(1 + \beta S)$$
The Type 2 Beverton-Holt equation is
$$R = S/(\alpha + \beta S)$$
The Ricker equation is
$$R = \alpha S \exp(-\beta S)$$
Functions
hconv(): Returns steepness (h) from alpha and phi0
R0conv(): Returns unfished recruitment (R0) from alpha, beta, and phi0
SRalphaconv(): Returns alpha from h and phi0
SRbetaconv(): Returns beta from h, R0, and phi0
