Oogenesis in fishes follows a universal plan; yet, due to differences in the synchrony and rate of egg development, spawning frequency varies from daily to once in a lifetime. Some species spawn and feed in separate areas, during different seasons, by storing energy and drawing on it later for reproduction (i.e. capital breeding). Other species spawn using energy acquired locally, throughout a prolonged spawning season, allocating energy directly to reproduction (i.e. income breeding). Capital breeders tend to ovulate all at once and are more likely to be distributed at boreal latitudes. Income breeding allows small fish to overcome allometric constraints on egg production. Income breeders can recover more quickly when good‐feeding conditions are re‐established, which is a benefit to adults regarding bet‐hedging spawning strategies. Many species exhibit mixed capital‐ and income‐breeding patterns. An individual's position along this capital–income continuum may shift with ontogeny or in relation to environmental conditions, so breeding patterns are a conditional reproductive strategy. Poor‐feeding environments can lead to delayed maturation, skipped spawning, fewer spawning events per season or fewer eggs produced per event. In a few cases, variations in feeding environments appear to affect recruitment variability. These flexible processes of energy acquisition and allocation allow females to prioritize their own condition over their propagules' condition at any given spawning opportunity, thereby investing energy cautiously to maximize lifetime reproductive value. These findings have implications for temporal and spatial sampling designs, for measurement and interpretation of fecundity, and for interpreting fishery and ecosystem assessments.

Otolith chemistry provides one approach for identifying the relative contribution of juveniles from different nursery habitats to adult populations. The goal of this study was to validate otolith element incorporation by quantifying the relation between otolith and water element concentrations (Sr/Ca, Mg/Ca, Mn/Ca, and Ba/Ca) as a function of differences in water temperature and salinity using juvenile gray snapper Lutjanus griseus, a reef fish that inhabits estuarine and nearshore habitats as juveniles. We investigated the effects of 20 different temperature (18, 23, 28, 33°C) and salinity (5, 15, 25, 35, 45) combinations on otolith element incorporation (partition coefficient D) in L. griseus. Temperature and salinity had significant effects on D Sr but no significant effect on D Mg or D Mn ; however, salinity had a significant effect on D Ba . The broad range of temperatures and salinities used in the present study encompasses those occupied by juveniles in the wild and therefore provides a realistic test for using otolith chemistry to infer environmental history of individual gray snapper. Element incorporation and the effects of temperature and salinity on element incorporation differ among fish species, limiting development of generalized models aimed at predicting water chemistry from otolith chemistry. Thus, the data presented here underscore the necessity of validation experiments to translate species-specific elemental signatures in otoliths.

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