NCCOS Project Explorer (NPE)

Ecology of invasive lionfish in the northwestern Atlantic and Caribbean(2009)

Project Description:
The rapid establishment of invasive lionfish in the Atlantic and Caribbean could impact native reef fish communities by direct or indirect competition for diet and/or reef space. Given the intensive fishing pressure on the reef fish complex, lionfish could occupy vacant niches thus hampering stock rebuilding efforts. Understanding the ecological interactions of invasive lionfish in their new environment is critical for predicting their impact. For this reason, we are assessing the nature of predatory interactions between juvenile lionfish and native predators. As predation mortality is a significant component of natural mortality of reef fishes, the quantification of predation pressure on juvenile lionfish is critical. Using laboratory and field based experiments, we are determining if native predators are capable of preying upon the venomous juvenile lionfish. We are also assessing lionfish movement around reef systems in the tropical Atlantic. Lionfish have been known to exhibit a home range, however, quantification of site fidelity has not be accomplished for lionfish. Using physical tagging, we are assessing the movement of lionfish in multiple habitat types including patch reef, mangroves, and expansive reef systems. Using these tagged individuals we are also assess in situ growth rates of lionfish at various sizes. Site fidelity and growth rates will provide important information for assessing recruitment intensity and feasibility of lionfish removal for mitigating ecological impacts. Lastly, we are conducting lionfish ethology (behavioral) assessments in various habitat types in the tropical Atlantic. We are assessing when lionfish feed, their behavior interactions with native reef fishes (i.e., competition for reef space), and their physical location in proximity to the reef habitat. These assessments are critical for understanding the nature of lionfish interactions with native fishes and thus their impact on the reef fish communities of their invaded range.

Expected Outcome:
By assessing lionfish ecological interactions with native fishes, we will be able to understand the scale of ecological impact. Based on preliminary observations, we anticipate that lionfish are capable of altering the forage fish community through direct predation on small fusiform teleosts. Given the high level of lionfish biomass (400 lionfish per hectare) observed in the tropical Atlantic, we expect that lionfish will compete directly with large piscivores for reef space. We also expect that lionfish exhibit high site fidelity in large complex reef systems, but will wander in patch reef systems as prey availability changes. We anticipate that no native reef fish will prey on lionfish with regularity and will actively avoid eating lionfish. It is by better understanding these ecological interactions that we will provide coastal managers with necessary information for mitigating the impacts of lionfish and thereby focusing resources where they are needed most.