Research

Research in the Aquatic Ecology and Astacology Lab involves a variety of aquatic biota in riverine, stream, floodplain, lake, wetland, and estuarine habitats throughout Louisiana.  Below are some examples of previous and ongoing research.

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Effect of hydrologic restoration activities on P. clarkii population characteristics in the Atchafalaya River Basin
Hydrologic restoration activities planned for The Nature Conservancy’s Atchafalaya Basin Preserve are aimed to improve flow patterns and water quality and ultimately reduce the extent, severity, and duration of hypoxia in restored areas.  We are working with TNC to examine P. clarkii population characteristics and physiological indices before and after these hydrologic restoration projects.  The information obtained will be used to evaluate the effect of restored water quality on P. clarkii populations and can be incorporated into future conservation and restoration decision activities.

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Red swamp crawfish Procambarus clarkii

Biotic and abiotic effects on Procambarus clarkii in the Atchafalaya River Basin
Over 90% of the wild crayfish harvest in Louisiana comes from the Atchafalaya River Basin, however, little research has examined the ecology of P. clarkii and the environmental factors that structure crayfish populations and harvests in this system.  My research examines how various biotic and abiotic factors (e.g., water quality, habitat characteristics, density) influence crayfish harvests and population structure.

Hypoxia
Hypoxic black water mixing with normoxic brown water.

Effects of environmental hypoxia on P. clarkii population characteristics
Spatially extensive and temporally persistent hypoxia in the ARB is associated with the annual floodpulse and floodplain inundation.  Crayfish and other aquatic biota are subjected to hypoxic conditions that can last for several weeks to months in many areas of the ARB.  I am examining crayfish population responses to environmental hypoxia by monitoring and comparing populations sampled from hypoxic and normoxic habitats throughout the ARB.

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P. clarkii hemolymph protein assay.

Physiological biomarkers of hypoxic stress in P. clarkii
Crayfish frequently encounter hypoxic conditions in aquatic and/or burrow habitats.  Physical responses by crayfish are often the result of physiological and behavioral responses to endure sub-optimal oxygen conditions.  My research investigates and quantifies several physiological biomarkers (hemolymph lactate, protein, and glucose concentrations) of hypoxic stress in crayfish from both field and laboratory experiments.

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Orconectes lancifer
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Orconectes palmeri ssp.

Distribution and life history of Louisiana crayfishes
Most people in Louisiana are familiar with our two commercially important crayfishes, the red swamp crawfish Procambarus clarkii and the southern white river crawfish Procambarus zonangulus.  However, most are unaware that Louisiana has approximately 39 species of crayfish within six genera.  I am attempting to fill in gaps and update our current knowledge on the distribution, life history, and ecology of crayfishes throughout Louisiana.

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Tagging a spotted gar.

Assessing the use of low-water refuges by fishes in river-floodplain systems
Seasonal inundation of river floodplains provides a mechanism of energy and nutrient transfer between the aquatic and terrestrial zones.  Many fishes in river-floodplain systems utilize nutrient-rich inundated floodplain habitats for feeding and spawning.  As flood waters recede, seasonally connected low-water refuges and back-water areas become important for fishes during low-water periods.  My research continues to document and quantify habitat characteristics and fish populations in floodplain back waters.

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