Stock Recruit parameters (Beverton Holt)

Author

Kaplan Issac

If you are using Beverton Holt stock recruitment in Atlantis, there are at least two variants. If you use flagrecruit = 3, initial guesses of the BHalpha and BHbeta parameter may be taken from stock assessments. These will need to be tuned, but the attached spreadsheet can be used as a starting point. It requires that you obtain, from stock assessments:

  1. Estimates of unfished # of recruits
  2. Estimates of unfished spawning stock biomass (SSBo) (total biomass of adults, both sexes)
  3. Steepness (h) , where   h  = (# Recruits when SSB = 0.2 * SSBo)/  (# Recruits when SSB =  SSBo)
    The sheet then translates these into BHalpha and BHbeta.  This has been used for California Current and Chesapeake Models, and any fixes or improvements are welcome. You need to calibrate a lot, even after obtaining these initial conditions. VertRecruitment_ForChesapeake.xls