Estimate mean weight (W) and mean (F) for the standard DEPM approach.

The standard DEPM approach does not use weight bins and does not require a set of weight class parameters. However, because of this it requires additional parameters for mean female weight (W) and mean batch fecundity (F). These are produced using this function and can be combined with the other weight invariant parameters (P0, A, S and R) using the combine_estimates() function. Two data.frames are required which contain weight data and batch fecundity data which can be used to estimated each of these parameters.

Estimate_mean_W_F(
  weight.data,
  TotalWt,
  GonadFrWt = NULL,
  Time = NULL,
  Region = NULL,
  parameters = NULL
)

Arguments

weight.data	Adult data used to calculate the mean total female weight (W). This data set should ONLY include females and should include variables for Total weight and/or gonad free weight (Total weight - Gonad weight). These are used to calculate mean W and provide estimates the intended weight estimates to the fecundity estimator.
TotalWt	The column heading in weight.data that represents Total Weight in grams
GonadFrWt	The column heading in weight.data that represents Gonad Free Weight in grams. If Gonad weight is not being used in the fecundity estimator (as total weight is used instead), then this parameter does not need to be specified.
Time	A string containing the column name for a timestep if desired as a grouping variable
Region	A string containing the column name for a region if desired as a grouping variable
parameters	A list of 4 starting parameters for the batch fecundity relationship that must include: "alpha", "beta", "Sigma0" and "Sigma1"

Value

A data.frame that includes the Mean W, variance of W, Mean F, variance of F, the covariance of the fecundity-at-weight data and Time and Region if grouping variables were provided