Life Sciences Commons^™

Development And Employment Of Environmental Dna Methods For The Detection Of Bull Sharks (Carcharhinus Leucas) In A Freshwater And Estuarine Interface In The Mobile-Tensaw Delta And Mobile Bay, Alabama, Katherine Schweiss

Master's Theses

Species conservation and management is influenced by the quality of monitoring methods employed, especially when targeting elusive, but ecologically significant species, like elasmobranchs. Bull Sharks (Carcharhinus leucas) are highly mobile predators that rely on estuaries and freshwater rivers for maturation, resources, and refuge; their ability to withstand changing environmental conditions may mean they are linking ecosystems through their habitat usage and movements. Rather than setting nets or attaching acoustic monitoring devices, which can be expensive, time-consuming, and invasive, the analysis of environmental DNA (eDNA) for tracing species presence was used to target C. leucasDNA. The present research …

Early Recruitment Of Crassostrea Virginica To Restored And Natural Oyster Reefs In The Western Mississippi Sound: Larval Supply And Post-Settlement Success, Leah Morgan

Master's Theses

The eastern oyster (C. virginica) is a foundation species that improves water quality, protects shorelines, provides refuge for other organisms, and contributes to commercial fisheries. Successful early recruitment of eastern oyster is vital for resupplying adult populations in the face of habitat loss. Coastal oyster populations are challenged by freshwater input, hypoxia, predation and overfishing. Consequently, substantial efforts have been dedicated toward oyster restoration within the northern Gulf of Mexico. The overall objective of this study was to consider the role and importance of early recruitment to oyster restoration in western Mississippi Sound. During the summer 2018 recruitment period, we …

Distribution, Abundance, And Trophic Ecology Of Anguilliform Leptocephali In The Northern Gulf Of Mexico, Lillian Collins

Master's Theses

All species of anguilliform eels have pelagic leptocephalus larval stages, which provides a means of monitoring the population dynamics of these otherwise cryptic and hard to study species. The goals of this study were to: 1) describe the distribution and abundance of anguilliform eel leptocephali across the northern Gulf of Mexico, and 2) examine the trophic ecology of leptocephali using stable isotope values of carbon and nitrogen (δ13C and δ15N). A 25-year (1990-2014) ichthyoplankton dataset provided by the National Oceanic and Atmospheric Administration (NOAA) Southeast Area Monitoring and Assessment Program (SEAMAP) was used to examine interannual variations in leptocephalus distribution, …

The Effect Of Historic Shipwrecks On Sediment Microbiomes In The Northern Gulf Of Mexico, Melissa Brock

Master's Theses

Microorganisms are ubiquitously distributed across all aquatic habitats, but it is the environmental conditions of a habitat that determine which microorganisms can thrive in terms of abundance or metabolic activity. Habitats that experience consistent physical and chemical environmental conditions repeatedly favor specific taxonomic groups which may result in a microbial assemblage that is commonly associated with that habitat (i.e., a core microbiome). Core microbiomes have been identified for a variety of natural marine habitats including methane seeps, wood falls, octocoral, and deep-sea sediments. However, it was unknown if the presence of man-made structures on the seafloor, including historic shipwrecks, also …

Evaluating Alternate Management Strategies For Spotted Seatrout (Cynoscion Nebulosus) In The North-Central Gulf Of Mexico, Nathaniel Wallace Jermain

Master's Theses

Spotted Seatrout (Cynoscion nebulosus) receive considerable fishing pressure as the most popular saltwater target species in the north-central Gulf of Mexico. The potential for alternate management strategies, including stock enhancement and reducing discard mortality, to support the sustainability of the stocks and the desires of stakeholders is unknown. The purpose of this study was to provide an objective evaluation of the efficacy of alternate management strategies for Spotted Seatrout in Louisiana, Mississippi, and Alabama. I used a management strategy evaluation (MSE) to measure the performance of 18 alternate management scenarios relative to control scenarios. Scenarios with a high …

Investigating Diel Periodicity In Export Flux In The Gulf Of Mexico Using A Particulate Imaging System, Justin Edward Blancher

Master's Theses

To estimate the diurnal periodicity in the biological pump, a floating array with a marine snow camera system at 150 m depth was used, and particles were imaged at a 40 second interval for a 24 to 30 hour period at five sites in the Gulf of Mexico in June 2017. Each image was processed to identify and size all the particles within the frame, which was then processed to determine diameter, an estimated volume, and settling speed for each particle. Using these parameters, particle mass was estimated using algebraically rearranged calculations for settling speed. Each hour during the deployment …

The Effects Of Salinity On Zootechnical Performance Of Spotted Seatrout (Cynoscion Nebulosus) In Recirculating Aquaculture Systems, Eric Gigli

Master's Theses

The spotted seatrout (Cynoscion nebulosus) is a euryhaline finfish candidate for marine aquaculture in the northern Gulf of Mexico. Aquaculture of this species currently uses salinities of 25 psu or greater making production challenging in areas where high salinity water is not available. This study aimed to document the effects of salinity on zootechnical performance of spotted seatrout embryos, early larvae, and juveniles in recirculating aquaculture systems to assist with the development of protocols for low salinity culture.

Embryos obtained from a volitional spawn at 29 psu were incubated at three salinities (12.5, 18.75, or 25 psu) until …