Internal function to optSR
getSR(pars, SSB, rec, SSBpR, mode = 1, plot = FALSE, type = c("BH",
"Ricker"))
an initial guess at model parameters steepness and R0
'observations' of spawning biomass
'observations' (model predictions) of recruitment
spawning stock biomass per recruit at unfished conditions
should fit (= 1) or recruitment deviations (not 1) be returned
should a plot of the model fit be produced?#'
what type of stock recruitment curve is being fitted ("BH" = Beverton-Holt or "Ricker")