Oogenesis and reproductive investment of Atlantic herring are functions of not only present but long-ago environmental influences as well

Significance Fish stock advice and management have a focus on protecting the reproductive capacity of a stock. Central to the associated research undertaken is whether spawning stock biomass is a proxy for total egg production. Here we demonstrate for the planktivorous Atlantic herring that the standard use of season-independent potential fecundity formulas may cause flaws in these interpretations. In particular, this would happen when the adults have experienced poor feeding conditions that negatively affect the reservoir of primary oocytes and thereby the future fecundity. Hence, females in excellent condition may show significantly lower-than-expected fecundity that could lead to errors in the judgment of reproductive capacity, especially under “red flag” situations.