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Full-Text Articles in Physical Sciences and Mathematics
Fishes Associated With Oil And Gas Platforms In Louisiana's River-Influenced Nearshore Waters, Ryan Thomas Munnelly
Fishes Associated With Oil And Gas Platforms In Louisiana's River-Influenced Nearshore Waters, Ryan Thomas Munnelly
LSU Master's Theses
A distinctive feature of coastal Louisiana is the unrivaled network of oil and gas installations (platforms) extending from inshore waters to the deep Gulf of Mexico. Since 2007 there has been a 38% reduction in platform numbers with the highest removal rates occurring in shallow (< 18 m) nearshore waters. Many fishes and invertebrates are attracted to platforms, presenting a unique opportunity to study detailed species-specific responses to the river-influenced hydrographic characteristics of Louisiana’s nearshore zone (5–25 km water depth). Prior studies of fishes around platforms focused on a few relatively large platforms in water depths ≥ 18 m. However, about one-third of all platforms are small, unmanned and non-drilling platforms located in waters < 18 m depth. Paired video and hydrographic data were collected at 150 small platforms in < 18 m water depth during the summers of 2013–2014. Fifty-four species of fishes were associated with small platforms. The assemblage(s) included juveniles of 29 species, indicating the importance of nearshore platforms as diverse nursery habitat. The coastal zone was divided into three regions based on broad-scale interactions between freshwater input and bathymetry driving major distinctions in interregional hydrography and fish assemblages. Co-occurring within this expansive artificial reef network is the second largest hypoxic area (dissolved oxygen (DO) < 2.0 mg l−1) on Earth. Platforms offer reef-like habitat features in the upper water column that may offer refugia for some reef-associated species during hypoxic events. Significant intraregional differences in physicochemical features were related to the presence of hypoxia (defined as DO < 50% saturation), as well as the distribution of sandy shoals. Eleven species accounted for most of the assemblage dissimilarities, composing ~93% of fishes observed. Habitat suitability indices for these 11 species provided information about habitat selection across horizontal and vertical physicochemical gradients throughout the coastal zone, and within hypoxic and well-oxygenated stratified water columns. East Bay, near the outlet of the Mississippi River, exhibited less hypoxia and a distinct fauna that included four adult goliath grouper (Epinephelus itajara). This endangered fish was observed during spawning season (summer), suggesting that East Bay might support a spawning aggregation.
Addressing The Land Loss-Fish Production Paradox, Kristy A. Lewis
Addressing The Land Loss-Fish Production Paradox, Kristy A. Lewis
LSU Doctoral Dissertations
Saltmarsh loss is occurring at high rates in Louisiana (LA), but understanding the impacts that marsh degradation has had on historical abundance of estuarine nekton in Barataria Bay, LA is lacking. I first examined the differences between fishery independent and fishery dependent data as indices of relative abundance. Previous studies used landings data to evaluate the importance of marsh habitat (e.g. distance of marsh edge and area of intertidal marsh) to fisheries production, but for most species, landings and survey data showed differing patterns of abundance through time. These findings emphasize the importance of using survey data (not landings data) …
The Role Of Climate Variability And Riverine Pulsing In The Community Dynamics Of Estuarine Nekton In Breton Sound, Louisiana, Bryan Patrick Piazza
The Role Of Climate Variability And Riverine Pulsing In The Community Dynamics Of Estuarine Nekton In Breton Sound, Louisiana, Bryan Patrick Piazza
LSU Doctoral Dissertations
Climate controls biotic community composition at multiple spatiotemporal scales through variability in environmental control mechanisms (assembly filters). This research investigated the role of climate variability in the community dynamics of estuarine nekton in Breton Sound estuary, Louisiana, and, specifically the effects of El Niño Southern Oscillation (ENSO), freshwater discharge, and a tropical cyclone. A teleconnection was found between ENSO and juvenile brown shrimp (Farfantepenaeus aztecus) abundance in Breton Sound from 1988 – 2007. ENSO affected winter weather conditions (air pressure, temperature and precipitation), and spring brown shrimp abundance in Breton Sound. Juvenile brown shrimp abundance lagged ENSO by …
Nekton Utilization Of Black Mangrove (Avicennia Germinans) And Smooth Cordgrass (Spartina Alterniflora) Sites In Southwestern Caminada Bay, Louisiana, Melanie Christine Caudill
Nekton Utilization Of Black Mangrove (Avicennia Germinans) And Smooth Cordgrass (Spartina Alterniflora) Sites In Southwestern Caminada Bay, Louisiana, Melanie Christine Caudill
LSU Master's Theses
This is the first study to compare nekton use and habitat value among Spartina alterniflora (Spartina), Avicennia germinans (black mangrove), and transition (S. alterniflora and A. germinans) sites within Louisiana's salt marsh-mangrove ecotone. Fishes and crustaceans were collected in Caminada Bay during fall 2003 and spring 2004 using 4 m2, bottomless lift nets. Although analyses were unable to demonstrate significant differences in fish (p=0.0753) and crustacean (p=0.1457) densities and species composition (p=0.8801) across sites, habitat-specific trends in nekton use were evident. Fishes, including gulf killifish and sheepshead minnows, showed affinities for the Spartina site, while crustaceans, especially white shrimp, were …