Intraspecific resource partitioning by an opportunistic strategist, inland silverside Menidia beryllina

Abstract

Seasonal variation in prey consumption and food resource overlap was evident in an inland water body for mature male, mature female and immature inland silverside (Menidia beryllina). During the first growth phase marked by intensive somatic growth by immature inland silverside, few adults were present in the population (28% of total catch), thus minimizing intraspecific competition for food resources between juvenile and adult inland silverside. During the second growth phase by adults, few juvenile inland silverside were present (0% of total catch) in the population, again minimizing intraspecific competition for food resources between juvenile and adult inland silverside. A divergence in food resource overlap was observed when mature male, mature female and immature inland silverside were present in the population. These population-level demographic responses to energy acquisition are likely necessary to maximize individual growth of mature male, mature female and immature inland silverside.