Energy Acquisition and Allocation to Egg Production in Relation to Fish Reproductive Strategies

Fish 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 common at boreal latitudes where productivity varies seasonally. Income breeding allows small fish to overcome allometric constraints on egg production and respond to current conditions; ceasing egg production when food is in short supply and resuming quickly when conditions improve. Many species exhibit mixed capital- and income breeding patterns, suggesting that breeding patterns are a conditional reproductive strategy that allows females to prioritize their own condition over their propagules’ condition at any given spawning opportunity, thereby expending energy cautiously to maximize lifetime reproductive value. 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 findings have implications for temporal and spatial sampling designs, and for interpreting fishery and ecosystem assessments.