Marine Biology Commons^™

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 …

Assessing Predator Risk To Diadromous Fish Conservation In The Penobscot River Estuary, Lauri Leach

Electronic Theses and Dissertations

Successful conservation of pinnipeds in the northwest Atlantic has led to increasing populations of harbor (Phoca vitulina) and gray seals (Halichoerus grypus) in the Gulf of Maine. Seals are often perceived as predators and competitors for fish, and as a result, come into conflict with fisheries and fish conservation. Increasing numbers of seals have become a recent concern in the Penobscot River Estuary in Maine, as habitat restoration and diadromous fish conservation have been top priorities in this region for the past decade.

To understand how pinnipeds are responding to these efforts, as well as the risks they pose to …

Characterizing The Diversity Of The Eukaryotic Microbiome In Marine Crustacean Zooplankton., Rose-Lynne Savage

Electronic Thesis and Dissertation Repository

Understanding zooplankton productivity is critical for modeling marine food web function, of which one poorly known factor is the influence of zooplankton symbionts. Zooplankton protist symbiont diversity is underestimated due to the limited surveys and techniques previously used. Using 18S V4 metabarcoding, I characterized the eukaryotic microbiomes associated with crustacean zooplankton from the northern Strait of Georgia, BC. Apostome ciliates were most abundant in all hosts except for cyclopoid copepods, which were dominated by Syndiniales. Most symbiont lineages were more abundant in one or two hosts, suggesting some degree of host preference. Microbiome data also provided information on diet, confirming …

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 …

From Phocine Distemper To Avian Influenza: A Study Of Immunogenetic Diversity In Two Sympatric Pinniped Species, Alayna K. Gigliotti

Electronic Theses and Dissertations

Gray (Halichoerus grypus) and harbor (Phoca vitulina) seals are sympatric species that inhabit the North Atlantic and have been subject to mortality events from disease outbreaks, particularly phocine distemper and avian influenza virus. Across mortality events, gray seals tend to exhibit a higher survival rate, which could be explained by various ecological factors impacting rates or direction of selection in parts of the genome related to the immune system. These factors could include haul-out site density, habitat, and degree of inter/intraspecies interaction. This research aims to compare genetic diversity within the Major Histocompatibility Complex (MHC) class …

Distributions And Abundances Of The Red Tide Dinoflagellate Alexandrium Catenella In The Eastern Gulf Of Maine And Bay Of Fundy In Relation To Diatoms In June, July And August Of 2019, Kimberly Lina D'Adamo

Electronic Theses and Dissertations

A series of three oceanographic survey cruises were conducted in June, July, and August of 2019 in the northeastern Gulf of Maine and Bay of Fundy. Surface water samples were collected and analyzed for enumerations of cell densities of the dinoflagellate Alexandrium catenella in relation to cell densities of diatoms. Hydrographic profiles of temperature, salinity, and nutrients (silicate and nitrate) were also made at each station. Data were analyzed to determine if there was any statistically significant evidence of allelopathic interference imparted by diatoms that impede A. catenella. A. catenella cells were most abundant in June, reaching 6,195 cells per …

Prioritizing The Largest, Oldest Corals For Disease Intervention In A Coral Disease-Ravaged Area: Southeast Florida Coral Reef Ecosystem Conservation Area, Alysha Brunelle

All HCAS Student Capstones, Theses, and Dissertations

Coral diseases appear to be more devastating than ever before. When a virulent disease ravages a coral ecosystem, it can significantly change the population’s demographics and cause local extinctions. Disease intervention response during such an event is impossible at a landscape scale, therefore priorities must be considered. Saving the largest, oldest colonies of reef-building species is a good choice due to their high fecundity and ecological function. Their size, as a proxy for age, is an indicator of their resistance to previous perturbations which may indicate higher fitness. Their size also provides habitat to many organisms and wave resistance in …

Surface Levels, Keisha Brathwaite

Electronic Theses and Dissertations

Surface Levels are depictions of unobserved and imperceptible realities of many phytoplankton exteriors. The exhibition explores various structures, textures, and repetitious forms from microscopic surfaces of objects that cannot be seen with unaided eyes. Electron microscopy is used to perceive and analyze these otherwise unseeable surfaces in depth. Magnifications provide a reference in creating three- and two-dimensional works that are minimalistic and abstract at a visible level. This abstract 3D/2D image collection is translated into material expressions using acrylic sheets, acrylic ink, and wood as the main media for construction of individual works. Collectively, they serve to make the invisible …

Fish Community Composition And Structure Near A Freshwater River Diversion In Southeastern Louisiana, Rachel L. Snider

LSU Master's Theses

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 …

Reproductive Effort Of Montastraea Cavernosa Across Depth In The Context Of Both Climate Change Refugia And Emergent Disease, Jeanne Bloomberg

LSU Master's Theses

As coral populations on shallow reefs decline globally, mesophotic coral ecosystems (MCE) have been suggested as potential coral refugia in the face of climate changes, leading to the development of a comprehensive deep reef refugia hypothesis. The current study assesses the climate and disease refuge potential of MCEs in the U.S. Virgin Islands (USVI) for the gonochoric, broadcast-spawning species Montastraea cavernosa. Polyp, population, and total habitat fecundities were estimated across the species’ depth range, and changes to population oocyte production over time due to recent ecosystem disturbances were considered. The number of gonads producing oocytes in each polyp and oocyte …

The Evolution Of Bivalve Shell Matrix Proteins, Mark Ira Duhon Ii

LSU Doctoral Dissertations

This dissertation focuses on the molecular underpinnings surrounding the evolution of the biomineralized shells of marine bivalves. Bivalve molluscs synthesize remarkably complex shells from calcium carbonate and an organic matrix of proteins secreted from the dorsal edge of the mantle. Molecular analyses of shell matrix proteins (SMPs) have suggested high rates of gene turnover despite the conserved nature of the shell itself. Here, I used proteomic and transcriptomic data to identify the SMPs and other biomineralization proteins from seven bivalve species that diverged 3-513 Mya. Contrary to previous studies that identified only a few shared biomineralization transcripts across the Bivalvia, …

Bull Kelp (Nereocystic Lutkeana) Restoration And Management In Northern California, Olivia Johnson

Master's Projects and Capstones

Northern California’s coastal marine ecosystems support one of the most productive and biodiverse habitats on the planet. Bull kelp forests (Nereocystic lutkeana) form habitats for an abundance of marine mammals, sea bird, fish, and invertebrates. In recent years, compounding ecological and climatic factors have disrupted the balance of the bull kelp forests and led to an unprecedented loss of bull kelp biomass and canopy cover. These areas that are typically teeming with marine life have shifted into a stable state of sea urchin barrens due to over grazing of bull kelp by purple sea urchins (Strongylocentrotus pupuratus). These sea urchin …

Sourcing And Evaluating The Use Of Detritus As A Supplementary Diet For Bivalve Aquaculture Using Stable Isotopes And Fatty Acid Biomarkers, Adrianus C. Both

Electronic Theses and Dissertations

Detritus is a ubiquitous component of ecosystems and an important fuel for secondary production. Due to the extractive nature of bivalve aquaculture, detritus is often incorporated into carrying capacity and growth models for cultured bivalves. However, despite the complexity and difficulty in obtaining direct measurements, detritus is often treated as a homogeneous food source in models. Further understanding the role detritus plays in the diet of cultured bivalves could lead to more comprehensive and accurate models as well as more informed site selection for growers. The purpose of this study was to assess the abundance, bioavailability, and contribution of detritus …

Steady Heartbeat: Field And Laboratory Studies Indicate Unexpected Resilience To High Temperatures For The Ribbed Mussel Geukensia Demissa, Ashlyn N. Smith Ms.

Honors College Theses

Salt marshes are important ecosystems found along the coast of Georgia. Salt marshes are hosts to diverse organisms that interact with each other to promote many ecosystem services, such as storm buffering and flooding, and absorption of excess nutrients. Among these diverse organisms is the ribbed mussel, Geukensia demissa. Mussels are a foundation species in this intertidal landscape, and without them the whole salt marsh would be negatively affected. The purpose of this investigation was to explore the thermal stress response of G. demissa to rising temperatures. Mussels were collected from three locations that were landlocked, close to a …

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 …

Sea Level Rise Vulnerability Analysis Of Mangrove Ecosystems Using Gis, Kayla Caldwell

HCNSO Student Theses and Dissertations

Climate change is accelerating beyond what is natural due to excessive emissions from human activities. The sea level has been rising for many years and is currently at a rate of 3.6 mm/yr. Mangroves are known to only keep pace with a sea level rate of less than 1.2 mm/yr. Mangroves are particularly vulnerable to rising sea levels if they are not able to keep pace through vertical sediment accretion or inland migration. To test the vulnerability of the south Florida mangrove ecosystems to sea level rise, this study analyzed changes in the mangrove forest coverage of the Oleta River …

Feeding Ecology Of Red Snapper (Lutjanus Campechanus) And Vermilion Snapper (Rhomboplites Aurorubens) Coexisting At The Louisiana Shelf-Edge Banks, Katherine M. Ellis

LSU Master's Theses

Niche partitioning, the process by which competing species use different subsets of the available resources, is commonly used to explain the coexistence of closely related species. In the northwest Gulf of Mexico on the shelf-edge banks, red snapper (Lutjanus campechanus) and vermilion snapper (Rhomboplites aurorubens) are two coexisting closely related species. Yet, little is known about how these species partition resources. In this study, niche partitioning of red snapper and vermilion snapper was investigated using gut contents and stable isotopes. While dietary niche partitioning was apparent, the species relied upon similar prey and displayed isotopic niche overlap, …

An Ecopath With Ecosim Analysis On Offshore Petroleum Platform Influences On Gulf Of Mexico Red Snapper, Valentin Gomez

LSU Master's Theses

Offshore oil and gas platforms have had a significant presence in the Gulf of Mexico since the 1950s. An important secondary function of these structures is that they provide artificial habitat to fisheries, most notably Red snapper. Policy changes intended to reduce the risk associated with aging infrastructure have reduced the number of standing platforms from 4044 to 1867 from 2001 to 2018. The effect this loss of habitat has on Red snapper was tested by creating three scenarios of platform changes and modeling the perturbation from 2005 to 2050. The simulation was accomplished using the ecological model Ecopath with …

Diet Analysis Of Stranded Bottlenose Dolphins (Tursiops Truncatus) In Virginia, Kristen Marie Volker

Biological Sciences Theses & Dissertations

This study describes the diet of bottlenose dolphins (Tursiops truncatus) stranded in Virginia via stomach content analysis and considers factors such as proportion of numerical abundance and reconstructed mass, frequency of occurrence, average reconstructed prey size, prey diversity and quantity, and otolith degradation code. Fish size was estimated via regression equations established from local fish collected during the study that derive wet weight directly from otolith length or width. Squid size is estimated from previously published equations. Soniferous fishes dominated the diet, especially Atlantic croaker, spot, and seatrout spp., adding evidence to the theory that bottlenose dolphins passively …

Natural Variation And Evolutionary Responses To Climate Change Stressors In Marine Invertebrates, Joanna Sarah Griffiths

LSU Doctoral Dissertations

Our rapidly changing climate is putting many species at risk of extinction and there is an urgent need to understand how species will respond to these changes. In this dissertation, I evaluate how three species of marine invertebrates (corals, oysters, and copepods) respond to stressful conditions in their current environments and how plasticity and evolutionary adaptation could alter their response to future climate change stressors. I first employed a space for time study to elucidate population differences in the response of cold-water corals, Balanophyllia elegans, to future ocean acidification. I found evidence that upwelling history (natural low pH exposure) influences …

Effects Of Freshwater Inflow On Nekton Assemblages And Blue Crab Populations In Southeastern Louisiana, Caleb Benjamin Taylor

LSU Master's Theses

Estuaries along the northern Gulf of Mexico represent some of the most productive ecosystems in the world, providing vital habitat for many recreationally and commercially valuable species, including the blue crab, Callinectes sapidus. The mixing of fresh river and saline ocean water in coastal estuaries contribute to this productivity. Dominated by large river influences and consisting of multiple estuaries, Louisiana contributes the largest commercial fishery in the Gulf of Mexico, and remains, on average, the largest supplier of blue crabs in the nation. However, across southeast Louisiana, freshwater flow is largely dependent on Mississippi River discharge, which is highly …

A Troop, A Raft, A Bed, Hanna Jane Guendel

Senior Projects Spring 2020

A Troop, a Raft, a Bed tells the interwoven fictional stories of three major animals (the mountain gorilla, the Adélie penguin, and the American eel) and four transitional animals (the white stork, the humpback whale, the common octopus, and the great white shark). The stories are told from the animals' perspectives, and are written with language that considers each animal's unique intelligence, mind, and behavior. These stories seek to communicate how animals around the world may be experiencing the various effects of climate change and global warming.

Estimating The Heritability Of Plasticity Of Thermal Tolerance And Its Application In The Restoration Of Endangered Caribbean Coral, Matz O. Indergard

UNF Graduate Theses and Dissertations

Abstract

Over the last two centuries anthropogenic activity has elevated atmospheric CO₂, creating a greenhouse effect that is predicted to elevate global temperatures 1-4^o C within the century. Increases in surface temperature pose a threat to the world’s coral reefs and have been the cause of many mass bleaching events. To combat this new threat, corals must migrate, acclimate, or evolve to rising temperatures. Phenotypic plasticity, or the ability of an individual to express different phenotypes to survive in different environments, is crucial for sessile organisms since it can increase survivability in species incapable of moving to …

Predicting The Impacts Of Climate Change On The Sandbar Shark And Cobia, Daniel P. Crear

Dissertations, Theses, and Masters Projects

A changing climate has been identified as a major driver of changes in marine species’ distribution, phenology, and habitat selection in recent decades and is expected to continue to influence these traits. These changes are not only happening in our oceans, but within coastal habitats as well, where waters are susceptible to sudden changes in temperature and oxygen levels are influenced by nutrient inputs. These changes which will likely impact fish species that utilize these areas as nurseries, spawning habitat, or foraging grounds. In this dissertation I consider climate impacts on two important predators, the sandbar shark (Carcharhinus plumbeus) and …

The Chumash Heritage National Marine Sanctuary: An Exploration Of Changing The Discourse On Conservation, Arielle Ben-Hur

Pitzer Senior Theses

In 2015, the Northern Chumash Tribal Council submitted a National Marine Sanctuary Nomination to establish the Chumash Heritage National Marine Sanctuary– a means by which to ensure the protection of one of the most culturally and biologically diverse coastlines in the world. On October 5, 2015, John Armor of the National Oceanic and Atmospheric Administration (NOAA) responded to the nomination, adding it to the inventory of areas NOAA may consider in the future for national marine sanctuary designation.

In my thesis, I explore how the nomination of the Chumash Heritage National Marine Sanctuary acts as a platform from which Traditional …

Distribution, Density, Movement, And Support For Management Of Mountain Sucker, Pantosteus Jordani, In The Black Hills Of South Dakota, Seth J. Fopma

Electronic Theses and Dissertations

Mountain Sucker, Pantosteus jordani, is a cold-water species native to the Intermountain West. Fringe populations of Mountain Sucker have experienced declines in recent decades. The population of Mountain Sucker found in the Black Hills of South Dakota represents the eastern fringe of the species’ native range. Recognized as both an indicator of biologic health and as a species of greatest conservation need in South Dakota, recent studies have suggested significant declines in both distribution and abundance. Despite the recent study of Mountain Sucker in the region, increased understanding of Mountain Sucker ecology is needed to effectively manage for the conservation …

A Mechanistic Understanding Of Range Expansion Of Invasive Blue Catfish In The Chesapeake Bay Region, Vaskar Nepal

Dissertations, Theses, and Masters Projects

Blue catfish Ictalurus furcatus is an invasive species of great concern in coastal habitats throughout the eastern United States, inclulding the Chesapeake Bay and its tributaries. In this dissertation, I use field surveys, laboratory experiments and quantitative modeling to provide insights into several aspects of blue catfish biology at the individual level. In chapter 1, I characterize and compare patterns in growth and body condition in blue catfish populations in the James and York river subestuaries during two stages of invasion. Both the mean growth rate and mean body condition of blue catfish declined in the recent period in response …

Multivariate Habitat-Based Predictive Modeling Of Three Demersal Rockfish Species In Central California, Georgia R. Martel

Cal Poly Humboldt theses and projects

Accurate, spatially explicit models of rockfish abundance are critical in implementing ecosystem-based management strategies and designating essential fish habitats and marine protected areas. Multibeam bathymetry methods and visual, non-extractive submersible transect surveys were combined to collect environmental variables and fish abundance data at three distinct sites within the study region. Zero-adjusted models were developed using habitat classification analyses of high-resolution (5 m) digital elevation models. Model accuracies were assessed by using a reserved subset of the original datasets. To demonstrate that a model’s predictive power was linked to its spatial origins, Mean Absolute Error and coefficient of determination values were …

Spatiotemporal Variability Of Rockfish Recruitment On California's North Coast In Relation To Habitat Availability, Carolyn Belak

Cal Poly Humboldt theses and projects

Characterizing primary drivers of temporal and spatial variability in recruitment is imperative to understanding the role of pre- and post-settlement processes influencing marine population dynamics. On benthic reefs, the quality and quantity of suitable settlement habitat can alter post-settlement density-dependent mortality rates and increase chances of survival. The north coast of California has experienced highly unusual oceanographic conditions in recent years, leading to severe loss of highly productive kelp forests and potentially deleterious ecosystem consequences. In the present thesis, I aimed to determine the effects of canopy-forming bull kelp (Nereocystis) and alternative complex habitats on the recruitment of …

Changes In Prey Mortality: The Efects Of Multiple Predators And Temperature On California Mussels, Wesley Hull

Cal Poly Humboldt theses and projects

Organisms serve as prey to a variety of predators within natural systems, detecting threats through physical and chemical means. While predator feeding behavior is also affected by the presence of other predators, it is unclear whether differing modes of detection have similar effects on predator feeding behavior. In rocky intertidal zones in northern California, the California mussel (Mytilus californianus) is a competitively dominant foundation species consumed by a variety of predators. I quantified the individual and combined effects of ochre star (Pisaster ochraceus) and rock crab (Romaleon antennarium) predation on mussels by implementing mussel …