Semester of Graduation

August 2020


Master of Science (MS)


Environmental Sciences

Document Type



Gulf of Mexico estuaries, particularly in Louisiana, are among the world’s most productive, with landings of commercially- and recreationally-important species exceeding all other contiguous US states. Coastal wetlands are disappearing at an alarming rate because they have been impounded from Mississippi River water and sediment. Although controversial, one proposed solution is to re-route the Mississippi River through diversions and siphons to supply the freshwater and sediments necessary to rebuild vanishing wetlands, particularly in Barataria Bay and Breton Sound, LA. This strategy is one approach outlined in the Louisiana Coastal Master Plan. This project aimed to describe the composition and structure of the fish community associated with the Caernarvon freshwater diversion in three microhabitats within Big Mar pond. These three habitats included Bayou Bonjour (shallow, slow-moving, protected habitat), Center Big Mar (shallow, slow-moving, submerged aquatic vegetation dominated habitat), and SW Big Mar (open water habitat). The fish community was dominated by a few ubiquitous species, and no differences were detected between the three sites. A single-species approach was adopted to determine how the three locations support the common species. Though the community did not vary, four of the five common species show evidence of an ontogenetic shift in habitat within Big Mar Pond. This work will inform fishers and policymakers on the impacts of the Mississippi River diversions and siphons on fish communities, especially as new diversion projects are proposed to restore eroding coastal wetlands and marshes.

Committee Chair

Linda Hooper-Bùi