The species we work with are located in the Mississippi River Valley watershed and the southeastern United States.
The pearl darter (Percina aurora) is historically endemic to the Pearl and Pascagoula river systems of southeastern Louisiana and southern Mississippi. Although recent data syntheses indicate populations are widespread and appear relatively stable in the Pascagoula River drainage, the species is likely extirpated from the Pearl River drainage following extensive anthropogenic modifications beginning in the 1950s. Recovery efforts to restore the species into the Pearl River drainage are currently in development; however, basic science gaps pertaining to the species’ biology and ecology limit our ability to designate and define tangible recovery goals and criteria. Working collaboratively with a variety of state and federal partners, we continue to fill data deficiencies related to basic population parameters (distribution, demographics, life history, and population genetics) and habitat requirements to inform management decisions and track recovery success.
The Gulf sturgeon (Acipenser oxyrinchus desotoi) is a large, long-lived, anadromous fish that was historically abundant across the northern coast of the Gulf of Mexico over the last 150 million years. The species was federally listed under the Endangered Species Act (ESA) in 1991 as a result of declining population trends. Habitat degradation and limited access to critical spawning areas continue to threaten Gulf sturgeon population recovery across the extent of its geographic range. Our office is working to protect and conserve this iconic species by identifying habitat-use that will inform management decisions and help design habitat restoration that will provide measurable benefits to the species’ recovery. We are also working to improve population numbers of Gulf sturgeon by developing a better understanding of the current status of the Pearl River population in order to evaluate the influence of various restoration efforts.
Many states in the south central region of the US have seen declines in alligator gar (Atractosteus spatula) populations in recent decades. Habitat alteration and overharvest contribute to various degrees in different parts of the range so restoration efforts are designed to meet specific geographic needs. The National Fish Hatchery system has been propagating and stocking alligator gar in efforts to achieve population restoration goals of the states; however, data gaps pertaining to post release survival limit our ability to determine the relative contribution of stocking efforts to restoration accomplishments. Together with partners, we will fill data deficiencies related to post stocking parameters (survival, recruitment, growth, environmental conditions) and develop a unified strategy with measurable metrics to define and evaluate restoration success and inform adaptive management decisions.
Louisiana pearlshell mussel
Historically, populations of Louisiana pearlshell (Margaritifera hembeli) have been limited to three tributary drainages of the Red River in central Louisiana. It predominately occurs in the high gradient reaches of headwater streams; however, these stream reaches tend to be the most highly susceptible to fragmentation effects due to anthropogenic barriers such as culverts associated with road crossings. Owing to the dynamics of the host-ectoparasite relationship, conservation of mussels is often intertwined with fish due to the obligate ectoparasitic stage of many freshwater mussels. Consequently, a more thorough understanding of current threats to connectivity by determining the adequacy of has been identified as a priority recovery action for Louisiana pearlshell. We are actively investing resources into robust assessments of stream network connectivity, local fish assemblage , and movement capabilities of potential host species to identify and prioritize Louisiana pearlshell management and restoration efforts.
American eel (Anguilla rostrata) are an important resource that serve as prey for fish, mammals, and birds, host species for freshwater mussels, support valuable commercial, recreational and subsistence fisheries and provide ecosystem balance. American eel migrate thousands of miles to complete a very complex lifecycle and populations have declined partially due to migratory obstacles and habitat loss. Together with numerous state and federal partners we are using acoustic telemetry to better understand adverse impacts to American eels migrating out of the Ouachita-Black-Red-Atchafalaya River navigation system, specifically, out migration success, chronology and migration triggers.
The frecklebelly madtom (Noturus munitus) has a broad but disjunct distribution, with populations ranging west from the Pearl River drainage of Louisiana and Mississippi, east to the upper Coosa River system of Georgia and Tennessee. Due to its fragmented range however, populations face differing threats and intensities of imperilment, necessitating drainage-specific recovery and restoration goals. Although recent surveys in the western portion of its range suggest populations display moderate levels of redundancy, threats resulting from the construction of the Tennessee-Tombigbee Waterway in the upper Tombigbee River drainage have likely extirpated the species from portions of its historic range. Together with numerous state and federal partners, we have initiated reintroduction efforts, along with integrating empirical studies assessing populations parameters and habitat use and suitability to identify and prioritize areas of high restoration potential to benefit frecklebelly madtom recovery efforts.