Michael Hoffman

Document Type

Internship Report

Publication Date

Spring 2015


Invasive lionfish have invaded the vast majority of the Atlantic and Caribbean Oceans, resulting in profound negative effects on native marine species and ecosystems via interspecific competition, direct predation, and trophic cascades. While complete eradication of these ravenous predators is now widely considered an impossible feat, controlling lionfish populations in sensitive and ecologically important areas may help to mitigate the pressure on native species in certain ranges. This study evaluated the recolonization rates of lionfish after removals were performed at seven natural and four artificial reefs throughout Biscayne National Park. The number of fish observed and removed from each study site was recorded to determine if significant differences existed in the recolonization of lionfish at varying depths and habitat types. Additionally, the size of each lionfish removed from each study site was recorded to ascertain whether the size of invasive lionfish changed significantly due to the repeated removals throughout the study. Overall, 212 lionfish were removed with a mean size of 29.46±7.21cm, and a removal success rate of 86.15%. A slight significant increase in the size of the lionfish collected throughout the course of the study was found coinciding with trends of increasing lionfish sizes since the beginning of the invasion of Biscayne National Park. Furthermore, a trend of increasing lionfish size with depth was discovered. No significant patterns in the recolonization rates of lionfish could be determined on artificial reef study sites, likely due to interference from public divers and spear-fishermen. However, an increase in lionfish recolonization on natural reef sites corresponded with increasing depth. Differences in the recolonization of lionfish and their respective sizes were also compared on a seasonal basis, between fall (July 16th 2014 – the last date a site each site was visited in November 2014), and winter (the last date each site was visited in November 2014 – April 30th 2015) seasons. No significant seasonal differences in the size or recolonization rates of invasive lionfish were found. These findings were used to form recommendations on the most effective weekly schedule of removals needed to prevent more than three invasive lionfish from inhabiting these areas.


Department: MBE

MPS Track: TME

Location: Biscayne National Park: Miami, FL

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