Feeding Ecology of Invasive Lionfish in Biscayne National Park, Florida
Indo-Pacific lionfishes (<italic>Pterois volitans</italic> and <italic>P. miles</italic>, “lionfish”) are venomous marine fishes that have recently invaded the Caribbean Sea, Gulf of Mexico, and western North Atlantic Ocean. Lionfish are generalist, opportunistic predators that consume a variety of invertebrates and small reef fishes such that the presence of lionfish can significantly reduce reef fish abundance, diversity, and recruitment on invaded reefs. This thesis is focused on the feeding ecology of lionfish in Biscayne National Park (BNP) located in southeast Florida. BNP consists of multiple diverse ecosystems, including mangroves swamps, seagrass beds, coral limestone keys, and the northern portion of the Florida Reef Tract, that support a diverse array of species and multi-million dollar fishing and tourism industries. These habitats within BNP are, however, at risk from the damaging predatory impacts of lionfish. Through morphological prey identification, supplemented with DNA barcoding for identification of highly-digested prey items, of stomach contents, lionfish diet is described by lionfish size, BNP location, and season. A total of 513 stomachs, containing more than 2600 prey items, were examined. Lionfish in BNP feed predominantly on small reef fishes and small crustaceans. Additionally, as lionfish size increased, a dietary shift from a primarily crustacean diet to a primarily fish diet was detected. Diet differed among BNP locations for medium-sized lionfish (100-179 mm TL), but not for large lionfish (≥180 mm TL). Conversely, dietary differences by season were observed in large lionfish, but no seasonal differences were detected for smaller lionfish (≤ 179 mm TL). Based on the diet habits observed, it is conservatively estimated that lionfish in BNP could consume nearly 600 kg of prey per hectare (ha) annually at an average density of 440 lionfish / ha, which could have significant ecological and economic consequences for BNP and south Florida.