Abstract
Since their introduction to the western Atlantic, invasive lionfish have had significantly harmful effects on tropical and subtropical marine ecosystems spanning along the east coast of the US, within the Gulf of Mexico, and the Caribbean. The invasion of lionfish is an issue calling immediate attention and has therefore set invasion ecology at the forefront of marine biological research. The concern for these harmful consequences is valid: one case study from the Bahamas revealed that lionfish populations had quickly expanded over six years to make up 40% of the total predator biomass, which coincided with a 65% decline in reef fish biomass (Green et al., 2012). While the literature has widely covered the invasion, many of these studies are inconclusive and open-ended. During the summer of 2016, I interned for the National Park Serive at Dry Tortugas National Park (DRTO), contracted to cull lionfish. Over the span of four months, and 105 hours of diving, our team’s grand total lionfish count was 66. I was surprised by the relatively low catch per unit effort, especially compared to our intern counterparts at Biscayne National Park (BNP). The purpose of this report is to summarize the most up to date research on lionfish and discuss potential reasons for the striking discrepancy in lionfish catch per unit effort between DRTO and BNP. The brevity of the internship, data availability, and time frame limit the conclusions that can be drawn; however, general observations were obtained. The number of lionfish caught in BNP was much greater than in DRTO, but the majority of those were in water deeper than 20; deeper than the majority of DRTO surveys completed. The result is a deep water refuge in BNP that is outside of recreational dive limits. There was no significant preference for habitat type; the most indicative factor concerning habitat was the presence of physical structure. Current plays a major role in larval distribution in that DRTO is upstream of BNP and is fed by the rest of the Florida reef tract. DRTO possesses some of the healthiest coral reefs in the invaded region which provides means for an innate immunity that BNP does not have, as well as the presence of large bodied native predators that may act as a form of biocontrol. Finally, the influence of humans, both direct and indirect, is more pronounced in Biscayne National Park, and may have a more significant role in the lionfish invasion. Understanding such patterns will deepen our understanding of this and other aquatic invasions, and may lead to new insights for management and improve control over the invasive population.