Yield per Recruit

Yield per Recruit (YPR) is a major revision of earlier implementations of the basic Thompson-Bell model for estimating the expected lifetime yield and biomass from a cohort subjected to varying levels of fishing mortality.

The present version incorporates estimates of life-history parameters such as mean age, mean generation time, reproductive value, expected number of spawnings, reproductive output from first-, second- and multiple time spawners. In addition the user can investigate the resulting age composition of catch and abundance under different levels of fishing mortality. Sensitivity analyses allow the user to investigate the influence of age at entry on the predicted yield and other population attributes.