Abstract

Invasive Pacific lionfish, Pterois volitans, were first reported in the Gulf of Mexico (GOM) in 2009 and since then have quickly become established on GOM artificial and natural reefs. Lionfish densities on northern GOM artificial reefs are currently among the highest reported in the western Atlantic, while their densities on natural reefs are at least an order of magnitude lower. As part of a broader study examining their impacts on native reef fishes, lionfish (n = 441) were collected with spears by SCUBA divers from March to September 2013 to evaluate differences in their feeding ecology at artificial versus natural reefs (depth range 20 - 40 m). Mean ± SE total length of lionfish samples from artificial reefs was 231.9 ± 3.0 mm, and was 225.6 ± 4.0 mm from natural reefs. Diet analysis revealed 86.7% of stomachs had prey present, with 55% of samples containing identifiable prey that consisted primarily of fish (88.7% of total dry mass) from 15 families. Juvenile vermilion snapper, an important fishery species, constituted 9.5% by dry mass of identifiable fish prey. Lionfish diet was significantly different between natural and artificial reefs (PERMANOVA, p < 0.001), with fish captured at artificial reefs having higher percentages of non-reef associated benthic fishes in their stomachs indicating movement of lionfish away from reefs to forage. Ongoing diet work is focused on examining seasonal and ontogenetic effects on lionfish diet, while changes in reef fish community structure and habitat utilization in response to invasive lionfish are being examined in complimentary research.

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