About This Project

We hypothesize that invasive lionfish settle in typical nursery habitats before searching out deeper, colder water. We will use otolith microchemistry to determine the differences between the most recent residency and the settlement location of lionfish individuals throughout Floridian waters.

Understanding their post-settlement behavior may help us control their population, limit future spread of the species, and decrease the negative influence of lionfish on native ecosystems.

Ask the Scientists

What is the context of this research?

Invasive lionfish first became established in the coastal waters of Florida, near Ft. Lauderdale. Currently, they have invaded coral reefs, mangrove, seagrass beds, and deep coastal water. Unrecognizable to native fishes, they eat whatever prey fits into their mouth. Furthermore, native predators have provide no top-down control on the invaders. They reduce biodiversity and are a threat to our native ecosystems.

Lionfish generally exhibit site fidelity but we lack long term data on lionfish spatial ecology and their settlement preferences. This is why approaching the question with stable isotopes will allow us to examine trends and behavior over a much larger time frame. This study will be the first to do microchemistry analysis on lionfish otoliths.

What is the significance of this project?

It is vital that we manage these lionfish populations as effectively as possible to reduce harmful effects on our fisheries and our ecosystems. Current removal efforts generally focus on spearfishing, but can also include trapping techniques. In many cases, spearfishing hasn't been enough, since some populations live deeper than safe diving limit. So, by learning about lionfish habitat use, we can target source populations or larval settlement habitats to improve current conservation efforts. Reducing the number of individuals that spread from source populations will help limit sink populations.

What are the goals of the project?

The purpose of this research is to determine if lionfish larvae settle in nursery habitats and how they disperse following settlement. I will age each individual fish by counting the otolith rings. Fish lay down layers of material on their otolith much like a tree lays down rings as it ages. For my stable isotope analysis, the juvenile core of the otolith will be sub-sampled using a micro-drill. Following this, a portion of the outer ring of the otolith will be sampled. These sub-samples will be analyzed for the isotopic ratios of O18, an indicator of ocean temperature, and C13, an indicator of different habitats. For each individual, differences between the two time-point sub-samples will indicate if movement away from settlement habitat occured.