Role of spawning condition in the determination of the reproductive traits of spring- and autumn-spawning Atlantic herring from the southern Gulf of St. Lawrence

Abstract

Mature spring-spawning (May–June) and autumn-spawning (August–September) herring differ in total weight. Autumn herring have both heavier gonads and higher somatic weights at length. Both the residual levels of storage lipids and somatic weight at length, corrected for storage lipid, are higher in autumn than in spring. Within spawning seasons, males and females deplete the same amount of storage energy. Percent somatic lipid content is positively correlated with body size during spring but shows no relationship to body size in autumn. These patterns indicate that the relative allocation of storage energy to reproduction differs with spawning season. Spring spawners (lengthy gonad maturation period) allocate proportionally more storage energy to routine and active metabolism than autumn spawners (brief gonad maturation period). The low intercept and steep slope of the gonad weight – length relationship for spring spawners reflect the interaction between decreasing metabolic rate with body size and increasing storage energy capacity with body size. Egg weight is unrelated to the parent's somatic lipid content for either spawning group. Spawning history (recruit versus repeat spawning) has only a minor influence on egg weight.