Marine Biology Commons^™

Evaluating Habitat Use By Nekton In Widgeon Grass (Ruppia Maritima), Shoal Grass (Halodule Wrightii), And Unvegetated Bottom Habitats In The Grand Bay National Estuarine Research Reserve, Jessica Woodall

Master's Theses

Seagrass beds support high biodiversity and animal abundance, serve as feeding grounds for a variety of animals, offer shelter from predation, and act as a nursery habitat for juveniles. The species composition of seagrass beds can impact their use as habitat by animals. Two common species of seagrass in the Gulf of Mexico are Ruppia maritima (widgeon grass) and Halodule wrightii (shoal grass). The shallow coastal waters of the Grand Bay National Estuarine Research Reserve (NERR) support both species, but the use of each seagrass as habitat by nekton is poorly understood, which can limit management decision-making. Nekton communities were …

Deep Ocean Vehicle Applications And Modifications, Nichole "Nikki" T. Arm

Master's Theses

This project had two primary goals: (1) to explore opportunities to further a deep-ocean vehicle’s reach using alternative pressure spheres, and (2) to implement an existing deep-ocean vehicle (lander) in active scientific research.

I gained a greater understanding of the limitations and design choices made for existing pressure spheres using Finite Element Analysis (FEA). My simplified FEA model predicted sphere failure for the existing 30% Fiber Glass 70% Nylon injection molded spheres at an external pressure of 3,954psi or 2,690m ocean-depth (only a 7.38% error compared to the tested minimum failure depth), so I determined it a valid model. I …

Effects Of Intertidal Position On The Response To Oxygen And Desiccation Stress In The Common Acorn Barnacle, Balanus Glandula, Megan M. Dotterweich

Master's Theses

Sessile invertebrates in the rocky intertidal experience intermittent periods of air exposure due to tidal flux, presenting risks of temperature extremes, hypoxia, nutrient limitation, and most dangerously, desiccation. Microscale variation in severity and frequency of these risks is widely dependent on vertical position within the intertidal zone. Common acorn barnacles (Balanus glandula) have a wide vertical distribution in the intertidal, creating large differences in microhabitat between the highest and lowest individuals in the population. This study set out to explore whether tidal position dependent differences exist in the response to oxygen and desiccation stress in B. glandula. …

Estimation Of Mortality Rates For The Gulf Menhaden Stock And Reference Point Implementation For The Fishery, Catherine Wilhelm

Master's Theses

The Gulf menhaden stock is the target of a large commercial fishery in the Gulf of Mexico. To address the needs of both the stock and fishery, I performed two studies. I first addressed the natural mortality rates currently used in the Gulf menhaden stock assessment. To update these rates, I used data from a tagging study conducted from 1970 to 1988. Adult and juvenile menhaden were tagged, released, and recovered in fish processing plants. To evaluate the data, I built a Bayesian model using the negative binomial distribution to estimate natural mortality, catchability, and the overdispersion factor parameters. I …

Rattus Norvegicus As A Biological Detector Of Clandestine Remains And The Use Of Ultrasonic Vocalizations As A Locating Mechanism, Gabrielle M. Johnston

Master's Theses

In investigations, locating missing persons and clandestine remains are imperative. One way that first responder and police agencies can search for the remains is by using cadaver dogs as biological detectors. Cadaver dogs are typically used due to their olfactory sensitivity and ability to detect low concentrations of volatile organic compounds produced by biological remains. Cadaver dogs are typically chosen for their stamina, agility, and olfactory sensitivity. However, what is not taken into account often is the size of the animal and the expense of maintaining and training the animal. Cadaver dogs are typically large breeds that cannot fit in …

Trace Dna Detection Using Diamond Dye: A Recovery Technique To Yield More Dna, Leah Davis

Master's Theses

This study aspires to find a new screening approach to trace DNA recovery techniques to yield a higher quantity of trace DNA from larger items of evidence. It takes the path of visualizing trace DNA on items of evidence with potential DNA so analysts can swab a more localized area rather than attempting to recover trace DNA through the general swabbing technique currently used for trace DNA recovery. The first and second parts consisted of observing trace DNA interaction with Diamond Dye on porous and non-porous surfaces.

The third part involved applying the Diamond Dye solution by spraying it onto …

Effects Of Shoreline Development And Freshwater Discharge On Nekton Assemblage And Trophic Structure In A Northern Gulf Of Mexico Estuary, Glenn Schumacher

Master's Theses

Coastal salt marshes support a diversity of nekton and facilitate critical ecosystem functions but are threatened by shoreline development and climate change. Therefore, coastal ecosystem managers have begun incentivizing the use of living shorelines (LS), erosion control structures incorporating native plantings, to mitigate ecological consequences of marsh loss. However, post-restoration climate changes may shift habitat templates and negate positive effects of ecosystem restoration. I evaluated the ecology nekton along LS, natural marshes, hardened shorelines and greyed shorelines within Biloxi Bay, Mississippi, during a high freshwater discharge (HFD) period by comparing nekton assemblage (using species richness, Shannon-Wiener diversity, and relative abundance), …

Induced Spawning Of Captive Tripletail Lobotes Surinamensis, Nicholas Adams

Master's Theses

The Tripletail, Lobotes surinamensis, is an emerging candidate species for U.S. marine aquaculture. This work aimed to address two bottlenecks for hatchery production of the species by developing a hormonal induction protocol to obtain fertile spawns from captive brooders and a method for sex identification of candidate brooders.

Single pairs selected among a captive-held broodstock conditioned under a natural photothermal cycle were induced with one of five treatments (n = 5 or 6 replicates per treatment). Control (no hormone) and hCG (1,100 IU.kg^-1 for females, 550 IU.kg^-1 for males) pairs did not spawn. Pairs treated with GnRHa …

Using Deep Learning And Uav Imagery To Detect Elkhorn Coral In St. Croix’S East End Marine Park, Samuel Wyatt

Master's Theses

Elkhorn coral, or Acropora palmata, is an important reef building species that promotes species abundance and other ecological services to the communities in the US Virgin Islands. We captured high resolution imagery of a reef in St. Croix’s East End Marine Park using a Wingtra One UAV. We then used deep learning techniques to detect individual coral colonies. We compared two deep learning models, FasterRCNN and MaskRCNN, and found that the models achieved accuracy shores up to 0.78. These scores improved when examining only larger corals in shallow waters. The model was able to both detect Elkhorn coral and …

Effects Of Intertidal Position On The Capacity For Anaerobic Metabolism And Thermal Stress Response In The Common Acorn Barnacle, Balanus Glandula, Kyra Anderson

Master's Theses

Intertidal habitats are characterized by dynamic, tidally-driven fluctuations in abiotic and biotic factors. Many of the environmental stressors that vary across the intertidal (e.g., temperature, oxygen, food availability, predation pressure) are strong drivers of metabolic rate in ectotherms. As such, we predicted that there may be pronounced differences in the metabolic and stress physiology of conspecific sessile invertebrates occupying at different relative tidal heights. The common acorn barnacle Balanus glandula represents an ideal model organism in which to investigate the possibility of tidal height-dependent physiological differences, owing to their wide distribution in the intertidal zone and their eurytolerant nature. In …

Polycyclic Aromatic Hydrocarbons And The Microbiomes Of Two Benthic Species, Samantha Ells

Master's Theses

The presence of oil has been shown to affect the microbiomes of the water column, sediments, and organisms, both by altering the diversity and the composition of those microbial communities. If the microbiome is altered it may no longer provide benefits to its host organism, impacting its ability to survive. Thus, it is important to understand the effects of large-scale contamination events including the Deepwater Horizon oil spill. This study set out to examine the effects of oil exposure on the microbiome of two benthic species, southern flounder (Paralichthys lethostigma) and eastern oysters (Crassostrea virginica) to further understand the effects …

Population Parameter Estimation And Stable Isotope Analysis Of Gulf Sturgeon (Acipenser Oxyrinchus Desotoi) In The Pascagoula River, Alfonso Cohuo

Master's Theses

Gulf Sturgeon (GS), Acipenser oxyrinchus desotoi, are a threatened, anadromous fish species in the northern Gulf of Mexico. Their range is from the Pearl River, LA, in the west to the Suwannee River, FL, in the east with a longitudinal divide at Mobile Bay, AL, creating a western population unit (WPU) and an eastern population unit (EPU). Sturgeon belonging to the WPU exhibit lower abundances, higher mortality rates, and are overall less studied than their EPU counterparts. Notable data gaps for the WPU includes the absence of recent population parameter estimations and confirmed feeding habitat. My thesis aims to …

Spatial And Seasonal Patterns Of Above- And Belowground Vegetation Biomass And Potential Drivers In The Pascagoula River Delta, Ms, Evan Grimes

Master's Theses

Coastal wetlands provide a valuable wealth of services to the greater coastal ecosystem and human communities. However, threats such as sea level rise and conservation projects, such as freshwater diversions, have the potential to alter coastal wetlands in different ways. In this thesis, I describe the effects of inundation and nitrogen on vegetation productivity using a field-sampling approach and an in situ controlled mesocosm experiment, called a marsh organ. The West Channel of the Pascagoula River contained significantly higher belowground biomass than the East Channel, which is more anthropogenically modified. Vertical distribution of belowground biomass did not strongly vary between …

Trophic Ecology Of Mesopelagic Fish Larvae And Juveniles In The Northern Gulf Of Mexico, Emily Gipson

Master's Theses

The deep-pelagic environment encompasses ocean waters below 200 m depth, and comprises 90% of the volume of the Gulf of Mexico. Deep-pelagic fishes are important prey for many oceanic consumers, but relatively little is known about their early life history, including larval fish trophic ecology. An understanding of the role deep-pelagic fish larvae have in oceanic food webs is important in the development of ecosystem models that examine the connectivity (via vertical migrations) between the deep-pelagic and epipelagic environments with respect to trophic interactions, nutrient cycling, and carbon sequestration. In this study, archived plankton samples collected during 2010 and 2011 …

The Response Of Marine Synechococcus To A Landscape Of Environmental Stressors: A Proteomic Exploration, Dana E. Michels

Master's Theses

In the field of marine microbial ecology, many questions remain unanswered with regards to the physiological trade-offs made by phytoplankton to maximize growth (e.g., nutrient acquisition) and minimize loss (e.g., predation defenses). These tradeoffs, which occur at the cellular level, have wide reaching impacts on food web dynamics and global biogeochemical cycles. In the first chapter, we explored the use of a non-canonical amino acid (NCAA) technique, bioorthogonal non-canonical amino-acid tagging (BONCAT), in phytoplankton model systems. This technique has potential to work well in natural systems by enabling isolation of only newly synthesized proteins during an incubation period with the …

Assessment Of Genetic Diversity In Largetooth Sawfish, Pristis Pristis, Populations Over The 20th Century, Ann Fearing

Master's Theses

The Critically Endangered Largetooth Sawfish, Pristis pristis, experienced global declines in range and abundance over the past century and Australia is now their last stronghold. This research aimed to understand whether these declines have been accompanied by a reduction in levels of genetic diversity. Using P. pristis tissue samples sourced from natural history specimens, three fragments (616-bp, 386-bp, 141-bp) in the mitochondrial DNA (mtDNA) control region were PCR-amplified. At each fragment, significant genetic structure was found in P. pristis overall (Φ_ST=0.946, N=9; 0.813, N=54; 0.771, N=99). The Indo-West Pacific and Atlantic/Eastern Pacific each harbor genetically distinct lineages of …

Microplastic Abundance, Distribution And Impacts On Sargassum-Associated Juvenile Fishes In The Gulf Of Mexico, Olivia Lestrade

Master's Theses

Microplastics are a concern in marine environments because they are highly durable, ubiquitous, and can be mistaken for food and ingested by small organisms. Pelagic Sargassum, an important habitat for larval and juvenile stages of many fish species, is found in large surface aggregations, and may provide complex structure in which microplastics become trapped. This could lead to greater risk of microplastic ingestion by fish early life stages associated with Sargassum habitats. To better understand the impacts of microplastics within Sargassum communities, this study examined 1) microplastic concentrations and ingestion by juvenile fishes associated with Sargassum; 2) the microbial …

Determining The Trophic Role Of Red Snapper (Lutjanus Campechanus) In Mississippi State Waters Using Stomach Content And Stable Isotope Analysis, Branden Kohler

Master's Theses

The goal of this study was to determine the diet composition, trophic position and ecological role of red snapper (Lutjanus campechanus) in Mississippi state waters utilizing stable isotopes (δ¹³C and δ¹⁵N) and stomach content analysis. Stable isotope analysis of fish and their prey can provide information on species-specific basal resource utilization, diet composition and trophic position which can improve food web models and inform fisheries management decisions. Particulate organic matter (POM), the presumed base of the food web, red snapper muscle tissue, and red snapper stomach contents were collected from 25 sites in 2016 and …

Transgenerational Plasticity Causes Differences In Uv-Tolerance Of Intertidal And Subtidal Populations Of The Purple Sea Urchin, Strongylocentrotus Purpuratus, Yareli Alvarez, Nikki L. Adams

Master's Theses

Planktonic larvae of marine organisms are increasingly being exposed and required to respond to a changing physical environment. Adult sea urchins occupy both intertidal and subtidal waters and broadcast spawn gametes into the water column to contend with variable physical conditions. To answer how populations of invertebrates residing at different depths adequately prepare their offspring to cope with different levels of ultraviolet radiation (UVR), we collected adult purple sea urchins, Strongylocentrotus purpuratus, from four sites (two intertidal and two subtidal (~15 m deep)) on the central coast of CA to compare UV tolerance in offspring. Our measurements of UVA …

The Effect Of Constant Relative Growth Rate Versus Constant Specific Growth Rate On Oocystis Sp, Rachel Kriner

Master's Theses

In this study, a strain of Oocystis sp. (S002) was grown using two different growth strategies at three different temperatures (15°C, 20°C, 25°C). One strategy (GS1) kept a constant specific growth rate (µ) and the other (GS2) kept a constant relative growth rate (µ/µ_max). In both strategies, the cultures were grown following the protocols of a hybrid growth system. The Dilution Phase is an initial semi-continuous growth phase that involves daily dilutions until set growth criteria are met. Followed by a batch culture growth protocol where the cultures were diluted at the onset of the first day and …

Quantifying The Ecological Drivers And Impacts Of Parrotfish Predation On Caribbean Corals Communities, Hannah Sima Rempel

Master's Theses

Parrotfishes (Scarinae) are dominant Caribbean herbivores that play an important role in reducing coral-algae competition by grazing algae; yet some species are also occasional coral predators (corallivores) and thereby can have direct negative impacts on coral growth and survivorship. There is concern that parrotfish corallivory may contribute to substantial long-term declines in targeted coral species, particularly in areas with a high biomass of parrotfishes and low cover of corals. However, the capacity of target coral species to heal from parrotfish predation and the ecological drivers of corallivory are poorly understood.

In Chapter 1, we examined the patterns of coral healing …

Cal Poly Pier Master Plan, Troy A. Lawson

Master's Theses

The Cal Poly Pier (Pier) Master/Facility Plan (FP) document provides the vision of the future for the Pier, a marine science research facility. The Plan facilitates project development and management of the Pier while meeting university and department research goals. Specifically, the FP document establishes goals and strategies to direct long-term development of the Pier, streamlines agency approval and permit requirements, provides context for pier management, and assists the permitting process for future development as it relates to regulatory permits and programmatic growth on the Cal Poly Pier to help meet goals of the Center for Coastal Marine Sciences (CCMS). …

Evaluating Methods To Reduce Humpback Whale (Megaptera Novaeamgliae) Ship Strike Mortality In Nearshore Feeding Habitats Within The San Francisco Bay, Alisa Keenan

Master's Theses

Across our world’s oceans, whales are perpetually stuck and killed by large ships. Sea-based commercial trade is increasing on a global scale; therefore, more large ships are circumnavigating through biologically important whale habitats. This is of grave concern to marine resource managers, especially in the United States where major shipping corridors overlap critical whale habitat. It is feared that in these areas with high whale density, ship strikes are reducing populations of whales to levels below what is sustainable for threatened and endangered species, thereby hindering the recovery of depleted whale populations. Humpback whales, a species that is federally-listed as …

An Analysis Of Dredge Efficiency For Surfclam And Ocean Quahog Commercial Dredges, Leanne Poussard

Master's Theses

Between 1997 and 2011, The National Marine Fisheries Service conducted 50 depletion experiments to estimate survey gear efficiency and stock density for Atlantic surfclam (Spisula solidissima) and ocean quahog (Arctica islandica) populations using commercial hydraulic dredges. The Patch Model was formulated to estimate gear efficiency and organism density from the data. The range of efficiencies estimated is substantial, leading to uncertainty in the application of these estimates in stock assessment. Analysis of depletion experiment simulations showed that uncertainty in the estimates of gear efficiency from depletion experiments was reduced by higher numbers of dredge tows per experiment, more tow overlap …

Vegetative Community And Health Assessment Of A Constructed Juncus-Dominated Salt Marsh In The Northern Gulf Of Mexico, Nickolas R. Murphy

Master's Theses

Deer Island is a coastal habitat which provides a buffer from storm and flood damage as well as shore-line stabilization to the mainland of Biloxi, Mississippi. A third of the land has been lost since 1850, largely driven by tropical storm and hurricane impacts as well as sea level rise. The United States Army Corps of Engineers and Mississippi Department of Marine Resources have targeted the shores of the island as sites for restoration using beneficial use dredged material, and two sites of differing age have since been planted with Spartina alterniflora, Juncus roemerianus, Uniola paniculata, S. patens, and Panicum …

Pismo Clams (Tivela Stultorum) In Califorina: Population Status, Habitat Associations, Reproduction, And Growth, Alexandria R. Marquardt

Master's Theses

Marine shellfish play a vital role in intertidal ecosystems and coastal communities, but many of these fisheries are small-scale and lack the necessary monitoring to ensure long-term sustainability. Effective management often requires information on key demographic parameters, such as population status, reproduction and growth. Pismo clams (Tivela stultorum) are a culturally important and iconic species in California, which supported a thriving commercial and recreational fishery throughout much of the 1900’s. However, Pismo clam populations have declined statewide in recent decades and are attributed to human harvest and predation by California sea otters (Enhydra lutris); However, no …

Patterns In Size Distribution And Catch Of Rockfish (Sebastes Spp.) In Fisheries-Independent And Fisheries- Dependent Hook-And-Line Surveys On The Central Coast Of California, Rose Elizabeth Dodgen

Master's Theses

Stock assessments are statistical models which characterize the state of a population of fish. Data for stock assessment models of West Coast nearshore groundfish come largely from fisheries-dependent sources. Incorporating fisheries-independent data would increase data availability. A potential source of fisheries-independent data which is comparable to existing fisheries-dependent data is the California Collaborative Fisheries Research Program (CCFRP), a Marine Protected Area (MPA) monitoring study. We are interested in understanding the context in which CCFRP could be implemented into assessments of nearshore groundfish, specifically rockfish. To investigate this, we used management-relevant metrics to examine three questions concerning the implementation of CCFRP …

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 …

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 …