`R/growthModels.R`

`SchnuteRichards.Rd`

The five-parameter growth function from Schnute and Richards (1990). Note that this function is slightly modified (a ‘+’ was changed to a ‘-’ so that the ‘a’ parameter will be positive) from the original in Schnute and Richards (1990)

SchnuteRichards(t, Linf = NULL, k = NULL, a = NULL, b = NULL, c = NULL)

t | A numeric vector of ages over which to model growth. |
---|---|

Linf | Mean asymptotic length. |

k | The "growth coefficient" with units of (year^(-c)). |

a | A dimensionless parameter |

b | A dimensionless parameter. |

c | A dimensionless parameter. |

`SchnuteRichards`

returns a predicted size given the provided parameter values.

None specifically, but 12-Individual Growth is related.

Schnute, J.T. and L.J. Richards. 1990. A unified approach to the analysis of fish growth, maturity, and survivorship data. Canadian Journal of Fisheries and Aquatic Sciences. 47:24-40.

See `vbFuns`

, `GompertzFuns`

, `RichardsFuns`

, `logisticFuns`

, and `Schnute`

for similar functionality for other models.

## See the formulae growthFunShow("SchnuteRichards",plot=TRUE)#> expression(E(L[t]) == L[infinity] * ~bgroup("(", 1 - a * e^{ #> -kt^{ #> c #> } #> }, ")")^{ #> frac(1, b) #> })## Simple examples ages <- 1:15 s1 <- SchnuteRichards(ages,Linf=100,k=0.03,a=0.01,b=0.005,c=2) plot(s1~ages,type="l",lwd=2)