Initial numbers and Beverton-Holt parameters

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

Usage

get_initial_numbers(B0 = 6400000, h = 0.7, 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 by get_phi().

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.