# Takes a fitted WHAM (Wood's Hole Assessment Model) and samples historical population and fishing dynamics from the MLE fit and variance-covariance matrix.

Source:`R/WHAM2OM.R`

`WHAM2OM.Rd`

Takes a fitted WHAM (Wood's Hole Assessment Model) and samples historical population and fishing dynamics from the MLE fit and variance-covariance matrix. Maturity-at-age-year, Mortality-at-age-year and weight-at-age-year are identical among simulations and are a direct copy of the matrices in the WHAM fitting object.

## Usage

```
WHAM2OM(
obj,
nsim = 3,
proyears = 30,
interval = 2,
Name = NULL,
WLa = 1,
WLb = 3,
WAAind = 1,
Obs = MSEtool::Imprecise_Unbiased,
Imp = MSEtool::Perfect_Imp,
nyr_par_mu = 3,
LowerTri = 2,
plusgroup = T,
altinit = 0,
fixq1 = T,
report = FALSE,
silent = FALSE,
...
)
```

## Arguments

- obj
a list object created by

`fit_wham()`

.- nsim
Positive integer. The number of simulations.

- proyears
Positive integer. The number of projection years for MSE.

- interval
Positive integer. The interval at which management procedures will update the management advice in runMSE, e.g., 1 = annual updates.

- Name
Character string. The name of the operating model.

- WLa
positive real number or array

`[sim, ages, year]`

. The default weight-length parameter a (W=aL^b)- WLb
positive real number or array

`[sim, ages, year]`

. The default weight-length parameter b (W=aL^b)- WAAind
positive integer. The index of the WHAM weight-at-age array input$data$waa to be assumed as the weight-at-age for the operating model

- Obs
The observation model (class Obs). This function only updates the catch and index observation error.

- Imp
The implementation model (class Imp). This function does not update implementation parameters.

- nyr_par_mu
Positive integer. The number of recent years that natural mortality, age vulnerability, weight, length and maturity parameters are averaged over for defining future projection conditions.

- LowerTri
Integer. The number of recent years for which model estimates of recruitment are ignored (not reliably estimated by the assessment)

- plusgroup
Logical. Does the assessment assume that the oldest age class is a plusgroup?

- altinit
Integer. Various assumptions for how to set up the initial numbers. 0: standard, 1: no plus group, 2: temporary fix for MSEtool plus group initialization

- fixq1
Logical. Should q be fixed (ie assume the F-at-age array faa is accurate?

- report
Logical, if TRUE, a diagnostic will be reported showing the matching of the OM reconstructed numbers at age vs the assessment.

- silent
Whether to silence messages to the console.

- ...
Additional arguments, including R0 (unfished recruitment), phi0 (unfished spawners per recruit associated with R0 and h for calculating stock recruit parameters),

## Value

An object of class OM.