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Current Thesis & Dissertation Research

Growth and condition of native Louisiana and Florida largemouth bass in Louisiana lakes

Melissa FriesFries, M. 2010. Environmental influences on individual growth and genetic composition of Louisiana largemouth bass stocks. M. S. Thesis. In progress.

Melissa is focusing her research on 12 lakes located throughout Louisiana that have been stocked with Florida largemouth bass over the past two decades. We have noticed substantial differences in bass growth, introgression, and individual condition these lakes, and Melissa is measuring numerous morphological, water quality, and habitat related variables in these lakes to see if we can determine why lakes differ in the composition and growth of their resident bass populations

Submerged woody structures

Submerged woody structure is one of the variables that may influence largemouth bass in these lakes

Important habitat variables

Another important habitat variable that may be affecting bass growth and condition is macrophyte density, particularly hydrilla, or in this case, duckweed

Recording water quality

Melissa is recording water quality with in situ monitors and basin morphology with a digital recording fathometer

Everyone loves crayfish

Everybody in Louisiana likes crayfish


Effects of stream stability on macroinvertebrate communities

Markos, P. D. 2010. Effects of stream channel stability on benthic macroinvertebrate communities in southeastern Louisiana. M.S. Thesis.

Peter is finishing up his research project on the effects of stream channel stability on habitat and macroinvertebrates in streams located in southeastern Louisiana. Peter incorporated the Pfankuch Index as a measure of channel stability in his habitat assessment, and found it to be highly correlated with many variables that we traditionally measure in stream habitat assessments. It appears that the index accurately reflected habitat conditions in these streams, and these qualitative measurements could easily be incorporated into our current stream habitat assessment procedures. 

Stream habitat conditions

Even though streams in the southeastern part of the state have relatively higher gradients, minimal flow and high densities of woody debris still characterize habitat conditions, even in small headwater systems

Sand substrates

Sand substrates characterize most of these streams, so woody debris is critically important for benthic habitat diversity.

The flashiness and instability of many streams in this ecoregion is reflected in the erosive bank along this stream.

 

Fish community habitat relationships in southeastern Louisiana streams

Ward, B. M. 2009. Effects of land use and habitat on stream fish assemblages in tributaries of the lower Bogue Chitto watershed, Washington Parish, Louisiana. M. S. Thesis. 

Brian is finishing up a project looking at the influence of water quality, reach-scale habitat, and watershed land use on the structure of fish communities in several tributaries of the Bogue Chitto River watershed in southeastern Louisiana. He visited his study sites four times each to get a good idea of community composition and variability within and among years, and we are curious whether we can detect land use effects on fish distribution and abundance. He has found substantial variability in physicochemical characteristics among sites, and we are analyzing his data to see if these site differences are reflected in the resident fish communities.

Finding fish

Numerous fishes were found in Brian's study streams, including striped mullet

Measuring habitat

Measured habitat characteristics included depth, flow, woody debris abundance, and substrate composition

Electrofishing

Backpack electrofishing units worked well in these streams, despite low specific conductance.

 

Disturbance ecology

Jonathan WestWest, J. L. 2010. Disturbance ecology of streams in southeastern Louisiana. Ph.D. Dissertation.

 

Jonathan is just beginning his research on the environmental structuring forces that shape the structure and function of coastal plain streams. We have numerous streams in the eastern portion of the state that were significantly impacted by Hurricane Katrina, and he would like to follow temporal patterns of community metabolism, periphyton abundance, and habitat diversity in these streams relative to streams that received little if any storm impact. Woody debris movement and the effects of woody debris abundance on stream habitats will likely play a major role in his research, as these streams are highly dynamic in terms of discharge and habitat structure. 

Finding fish

During the growing season, streams throughout southeastern Louisiana are often characterized by low gradients, fine substrates, high organic loads, and marginal dissolved oxygen levels.

Measuring habitat

Although often supporting high densities of woody debris, many streams offer little habitat complexity in the form variable depths, flow velocities, and substrate types, yet often yield a relatively high diversity of fishes and invertebrates.


Life history of alligator gar

Kayla DiBenedetto DiBenedetto, K. C. 2009. Life history characteristics of alligator gar, Atractosteus spatula, in south Louisiana. M.S. Thesis.

Kayla is investigating several basic life history parameters of alligator gar, a species that has declined throughout much of its historic range, but appears to be thriving in south Louisiana and currently supports a small commercial fishery. She is looking at aging techniques, growth, and reproductive ecology, and has collected over 300 gar for her project with the help of a commercial fisherman.

Gar ovaries

Gar ovaries are supposed to be highly toxic, but Kayla is still here

Impressive fish!

Impressive fish, but these are small relative to historic records

Alligator gar teeth

The business end of a small alligator gar, imagine the mouth of an 8-footer, pretty efficient predators!