Drivers of lionfish spatial distribution in shallow fore-reef environments in the Caribbean

Supervisor: Manuel Gonzalez-Rivero (Global Change Institute, University of Queensland)
The invasion of the Caribbean Sea marine habitats by two predatory Indo-Pacific lionfish species, Pterois volitans and P. miles, is one of the fastest ever documented for a marine fish. Having successfully established populations in all subregions of the Caribbean, the lionfish has emerged  as a major threat for coral reef communities across the whole region. Coral reefs in the Caribbean are already under severe ongoing stress as a result of intense human activity in the area, and the additional impact of this remarkable invader has resulted in enhanced ecosystem disruption and the accelerated loss of coral and fish species. Lionfish are habitat generalists able to occupy diverse environments and are able to withstand adverse conditions, and this plasticity and resilience could be playing a major role in their invasive success.
Utilizing the extensive photographic record acquired through the Catlin Seaview Survey at four  different subregions within the Caribbean (Lucayan Archipelago, Mesoamerica, Southern Caribbean and Lesser Antilles), the present study investigates lionfish spatial aggregation and abundance in shallow fore-reef environments within this range. The effect of abiotic factors as drivers of its distribution, including coastal development, overfishing, marine-based pollution, sedimentation and protection status of the reefs, was explored through the application of Generalized Linear Mixed-Effect modeling. Additionally, rugosity was included as a proxy for reef habitat complexity to explore its effect on lionfish abundance, as it relates to the availability of predation refugia, reproduction shelter and food availability. Lionfish distribution was observed to be spatially heterogeneous among and within subregions, clustering within a distance of 40 m. While habitat complexity does not seem to be a major factor driving lionfish abundance, the results of the GLMM modeling  suggest  that habitat degradation due to anthropogenic stressors could be facilitating the establishment of an invasive opportunistic species such as the Indo-Pacific lionfish.Keywords: Lionfish distribution, Pterois, invasive species, coral reefs, Caribbean,  reef