NCCOS Project Explorer (NPE)

Assessments of lionfish trophic impacts(2010)

Project Description:
This project is utilizing laboratory and field-based studies to assess the potential trophic impact lionfish in the Northwestern Atlantic, Gulf of Mexico, and Caribbean. Invasive lionfish have become widespread along the U.S. Southeast Coast and Caribbean. Until recently, invasions of finfish in marine ecosystems have been considered of minor consequence; however, lionfish have been observed to reduce recruitment of forage fishes by nearly 80% on tropical patch reefs. Significant ecological impacts might occur if lionfish continue to increase and out-compete native reef fishes. Concerns about the invasion of the lionfish are based on its presumed position at the top of the food chain. Despite no known predators, their life history and foraging habits could make them direct competitors with many species among the snapper-grouper complexes of the western north Atlantic and Gulf of Mexico and the coral reef fishes of the Caribbean. We believe that lionfish are functional equivalents to these species, and their introduction and establishment will have measurable affects on community composition and food-web dynamics of coral reef and hard bottom communities. We are measuring bioenergetic parameters of lionfish in the laboratory and are estimating lionfish metabolic processes (i.e., maximum consumption, respiration, and excretion) at a range of realistic temperatures encountered by invasive lionfish. These experiments are determining size dependent energetic requirements of lionfish and will result in direct calculation of trophic energy lionfish are removing from reef fish communities through predation. We are compiling a comprehensive diet analysis for lionfish collected from the tropical Atlantic. This research is documenting the composition of lionfish diet and is capable of comparing diet overlap with native predators. We are developing spatially explicit forecasts of trophic impacts from lionfish by integrating bioenergetics assessments with the known bottom habitats of the Western Atlantic, Caribbean, and Gulf of Mexico. These forecasts will provide coastal managers with a relative assessment of the potential threat of lionfish to locally important fisheries and could be used to mitigate the impacts of lionfish to these valuable fisheries resources. This information will be coupled with spatially explicit datasets to produce a descriptive index of the optimal habitat for lionfish. This in vitro information will be combined with in situ SEAMAP bottom habitat profiles, bottom temperature measurements, and sea surface temperature measurements to predict the locations where lionfish bioenergetic demands will impact fisheries resources. These efforts will quantify the impact from lionfish on food web dynamics in invaded and un-invaded habitats. Using this information and literature derived values, we are developing a model capable of exploring life-stage sensitivity in a lionfish population model.

Expected Outcome:
This project will provide an assessment and prediction of lionfish trophic impacts at the local, regional, and international scales. We anticipate that lionfish consumption of native forage fishes will cause direct and/or indirect impacts on native reef fish communities. This project is providing the first evidence and predictions of the trophic impacts of a non-native marine finfish. Using a lionfish optimal habitat map, provided by this study, coastal managers will be able to determine the relative threat from lionfish to local reef fish communities.