Initial numbers and Beverton-Holt parameters

Computes the initial equilibrium numbers-at-age, unfished recruitment (R0), and Beverton-Holt stock-recruitment parameters.

Usage

get_initial_numbers(B0, h, M_a, phi_ya)

Arguments

B0

Numeric unfished spawning biomass.

h

Numeric Beverton-Holt steepness parameter (typically 0.2-1.0).

M_a

A vector of natural mortality rates indexed by age.

phi_ya

A matrix of spawning output-at-age with dimensions year by age (created using the get_phi function).

Value

A list containing:

Ninit

Vector of initial equilibrium numbers-at-age.

R0

Numeric unfished recruitment (scalar).

alpha

Numeric Beverton-Holt alpha parameter.

beta

Numeric Beverton-Holt beta parameter.