Potential Errors in Measuring Spawning Stock Biomass: Determining the Effects of Non-Participatory Adults for Some Atlantic Groundfish Species

Using both old data sets and recent information there are indications that the estimates of spawning stock biomass have been over-optimistic for some commercially important groundfish species.The concept of non-participation had been used for adults, which undergo gametogenesis but fail to spawn successfully, or which have very low participation because fecundity is extremely low for an individual, in comparison to others of the same species.Interannual variability in production of fertilized eggs may also be due to the presence of adults which do not undergo gametogenesis every year and this situation may be much more common than has been previously accepted in setting up stock-recruitment models.Re-calculations of spawning stock biomass for some groundfish species using lower and more realistic participation rates should provide better understanding of stockrecruitment relationships.