1) Systematics, taxonomy, biogeography, and diversification of North American fishes
My lab addresses questions of fish taxonomy, systematics, biogeography, and diversification using a variety of analytical approaches. These areas represent the core research focus in my lab. I have used traditional Sanger sequencing, as well as genomic and next-generation sequencing approaches (UCE, Anchored Hybrid Enrichment, SNPs) to generate data rich phylogenies that I use as historical templates to test biogeographic hypotheses, to examine diversification rates, to estimate the timing of clade divergence, and to investigate the evolution of particular ecological characteristics and morphological features. I plan to continue to focus on studying the diversity of various fish groups throughout Mexico, Central America, and the southeastern United States. In particular, I have lead more than 25 research expeditions to Mexico and Central America. Current projects include phylogenetic studies of silversides (Atherinopsidae), splitfins (Goodeidae), poeciliids (Poecilidae), cichlids (Cichlidae), and darters (Percidae).
2) Population and conservation genetics
Understanding genetic variation within and among populations is critical to protecting, conserving, or managing any species. I have received substantial funding to conduct population genetic studies of various marine, estuarine, and freshwater fish groups in the Gulf of Mexico including recreationally/commercially important species as well as state and federally imperiled species. I have used DNA sequences, microsatellites, and SNPs to address a wide variety of questions regarding gene flow and genetic structure. My lab has also applied these approaches to non-game fishes to examine rates and direction of gene flow with and among populations. This area of research has consistently been an important component of my research program.
3) Conservation and natural history of North American freshwater fishes
A large percentage of the non-game fishes throughout the eastern United States, Mexico, and Central America are in jeopardy. Most of the impacted species are sensitive to changes in water quality and substrate stability, land use changes, and introductions of exotic species. My lab has long been involved in studies that have utilized field intensive surveys, data/specimens from natural history collections and most recently, environmental DNA monitoring (eDNA) to determine the conservation status of rare and endangered fishes and to assess the benefits of artificial reefs in coastal Louisiana. The combination of field and lab work (i.e., gathering of life-history data, quantification of ecological characteristics, the examination of long-term population trends from natural history collections, eDNA) have aided in understanding the factors important in the decline of species, as well as documented the existence of rare fishes when traditional sampling has failed.