Ontogenetic diet shifts in Nassau grouper: Trophic linkages and predatory impact

摘要: Understanding which fauna and flora from seagrass beds serve as primary food for reef-based commuters is critical in defining trophic linkages between shallow-water habitats of tropical oceanic regions. Although numerous studies have documented the relative importance crustaceans diet reef fishes associated with meadows, it unknown if corresponds to a significant effect on prey distribution abundance patterns. We quantified size-specific juvenile Nassau grouper (Epinephelus striatus) inhabiting natural artificial patch reefs, manipulated density reefs (0, 8, 16 per ha) examine predatory impact associates nocturnally foraging crabs. Stomach content analysis indicated an ontogenetic shift diet, where small ( 30 cm TL) consumed primarily fish. Mid-size fish (20.0-29.9 were transitional occurring more frequently than Diet was least diverse large fish, nearly identical mid-size Similar numbers taxa ingested reefs. Before deployed field, nighttime band censuses revealed mean 3 crabs 240 m 2 (ranges = 0-8 crabs/transect) nearby beds. After deployed, crab densities dropped by one-half 43-fold sites compared control (0 reefs). There negative relationship (no. ha -1 ) -2 at all locations combined. These results suggest that predators adjacent highlight important link habitats.