Harvest reference points for the Beverton and Holt dynamic pool model

Abstract Harvest reference points were obtained for the Beverton and Holt dynamic pool model using concepts from surplus production models. The conventional approach for estimation of an optimum fishing mortality for the Beverton and Holt model, F MAX , balances growth against mortality, but the relation of yield to fishing mortality is asymptotic when natural mortality is high relative to growth and a maximum yield does not exist. The method proposed here uses the Beverton and Holt model to calculate fishing mortalities at optimum proportions of the carrying capacity that were identified using surplus production models. The new method can give values similar to F 0.1 , but they are optimum values with a theoretical basis. The new method was applied to several species and the results were compared with F 0.1 and with F MAX . For all species fishing mortalities obtained with the new method were smaller than F MAX and they should maintain a higher stock size and have a lower risk of poor recruitment.