Age Composition of the Spawning Stock Does Not Always Influence Recruitment

The concept that the age composition of the spawning stock is an important determinant of recruitment is wide-spread. However, the number of populations and species where this has actually been studied is fairly limited. This study explores the effect of age composition on recruitment in one American plaice (Hippoglossoides platessoides) and three Atlantic cod (Gadus morhua) populations. Both the effect of age diversity and the effect of the presence of first time spawners are explored. No consistent relationship between age composition of the spawning stock and recruitment was found for the populations examined. We conclude that age composition of the spawning stock may not be universally important. Further research is needed to explore how common the effect of age composition on recruitment is and under which conditions age composition exerts an important influence on recruitment.