simAges {FSATeach} | R Documentation |

Constructs either a simulated age frequency table or individuals that follow a simulated age frequency table. The number of individuals at each age is determined from an initial cohort size and an instantaneous or annual mortality rate supplied by the user.

simAges(N0 = 500, A = 0.3, Z = -log(1 - A), incl.zero = FALSE, max.age = NULL, indivs = TRUE, rand = TRUE)

`N0` |
A numeric representing the initial cohort size to be used in the simulations. |

`A` |
A numeric representing the annual mortality rate to be used in the simulations. |

`Z` |
A numeric representing the instantaneous
mortality rate to be used in the simulations. Will
default to the value that corresponds to the user
supplied value for |

`incl.zero` |
A logical indicating whether age-0
should be included in the ouptut ( |

`max.age` |
A numeric indicating the maximum age to
use in the simulations. If |

`indivs` |
A logical indicating whether the output
result should be ages assigned to individual fish
( |

`rand` |
A logical indicating whether the individual
ages should be chosen randomly ( |

The heart of this simulation is the assumption of an
exponential decay model that starts with `N0`

individuals at age-0 and estimates Nt individuals at each
age t, from 0 or 1 (depending on the `incl.zero`

value) to `max.age`

, with Nt=N0*exp(-Zt). If
`indivs=FALSE`

then the ages (t) and frequencies
(Nt) are output as a data frame. If `indivs=TRUE`

(default) and `rand=FALSE`

then the age frequency
values are used to deterministically produce ages for
individual fish – i.e., essentially `rep(t,Nt)`

.
Finally, if `indivs=TRUE`

(default) and
`rand=TRUE`

(default) then the age frequency values
are used to stochastically produce ages for individual
fish – i.e., essentially
`sample(t,sum(Nt),replace=TRUE,prob=Nt/sum(Nt))`

.

Either a data frame containing the ages and the simulated
number of fish at each age (i.e., when
`indivs=FALSE`

) or a vector containing the simulated
ages for individual fish (i.e., when `indivs=TRUE`

;
default).

`simLenFromAge`

, `simLenSelectP`

,
`simLenSelectM`

## set seed for repeatability set.seed(5234734) ## Simulated individual ages (random) bg.ages <- simAges(N0=500,A=0.35) str(bg.ages) table(bg.ages) ## Simulated age frequency (non-random) bg.ages.sum <- simAges(N0=500,A=0.35,indivs=FALSE) str(bg.ages.sum) t(bg.ages.sum) ## Simulated individual ages (non-random) bg.ages2 <- simAges(N0=500,A=0.35,rand=FALSE) table(bg.ages2)

[Package *FSATeach* version 0.0.1 Index]