Marine Biology Commons^™

Trophic Ecology Of Black Swallowers (Scombriformes: Chiasmodontidae: Chiasmodon) In The Deep-Pelagic Gulf Of Mexico, Travis J. Kirk

All HCAS Student Capstones, Theses, and Dissertations

The ecology of deep-pelagic predatory fishes remains poorly understood despite their importance as ecosystem regulators and energy transfer vectors. This study investigated the trophic ecology of three species of the predatory fish genus Chiasmodon (“black swallowers”) in the Gulf of Mexico, a region that serves as an analog for the global low-latitude deep pelagial, the world’s largest cumulative ecosystem. Foraging habits (e.g., selectivity, chronology, daily ration) of an “advanced” evolutionary fish in a system that is otherwise dominated by basal fish taxa, were quantitatively estimated via high-resolution stomach content analysis. A quantitative dataset of both predator and prey abundance, the …

Addition And Subtraction: Coral Reproduction And Disease In A Changing Ocean, Ashley Rossin

LSU Doctoral Dissertations

Marine diseases are changing the landscapes of coral reefs particularly throughout the Western Atlantic. Stony coral tissue loss disease (SCTLD) swept through this region impacting at least 22 stony coral species. White plague (WP) is a more ephemeral disease, but still has a significant impact on coral reef health and perseverance, especially under a changing ocean. While these impacts are seen on the reef-scale, we can zoom into the tissue-level to identify disease markers for both diseases and identify their differences. This has ramifications for disease intervention, as well as mitigation strategies. Despite continuous disease outbreaks, healthy corals persist and …

Quantifying The Respiratory Plasticity Of Common Fishes Of The Indian River Lagoon, Logan Exton

Honors Theses

Increasing water temperatures resulting from global climate change introduce new energetic demands for marine organisms. Higher energy input will be required to cope with a subsequently higher metabolic rate, affecting all aspects of an individual’s life and therefore their survival. Because estuaries act as a link between rivers and oceans, they and their inhabitants are considered to be the most threatened by climate change. Therefore, it is crucial to understand how these organisms will respond to increased stressors due to climate change. Checkered pufferfish (Sphoeroides testudineus) are among the most common teleost fish in the Indian River Lagoon, …

Density Dependent Calling Behavior In North Pacific Humpback Whales, Lucas J. Anderson

Honors Theses and Capstones

Animal density can define factors such as mating success, food acquisition, and communication. Inferring animal density from vocal rates is an important tool for estimating abundance and space use in difficult-to-study species like marine mammals and requires an understanding of the relationship between social context and calling rates. The goal of this project was to investigate the relationship between animal density and call rate in Southeast Alaskan humpback whales (Megaptera novaeangliae). Passive acoustic monitoring data were collected along with visual observations gathered near Frederick Sound and Stephen’s Passage, Southeast Alaska, over two summers (2019, 2022). Observers watched whales …

Tropical Fish Study In Tahiti, French Polynesia, Miranda Brainard, Caitlyn Swango, Paityn Houglan, Richard Londraville

Williams Honors College, Honors Research Projects

In May of 2023, I embarked on an exciting research journey to Moorea, French Polynesia, alongside fellow students and faculty members from the University of Akron and Syracuse University. This expedition was part of the university-sponsored Tropical Vertebrate Biology course, where we delved into the exploration of various tropical species inhabiting the island, including sea urchins, geckos, and my primary focus, the blackspotted rockskipper.

My research team, composed of my co-authors and me, was particularly intrigued by the unique refuge-seeking behavior displayed by blackspotted rockskippers. These amphibious fish are renowned for their remarkable ability to inhabit tide pools and rocky …

Considering Tidal Flooding To Provide A Holistic Approach To Nutrient Input Management, Mary Beth Armstrong

Dissertations, Theses, and Masters Projects

This report explores the integration of tidal flooding impacts into nutrient management frameworks for the Chesapeake Bay, a potentially large gap in current strategies. Coastal communities in the Chesapeake Bay, face an increasing threat from tidal flooding—also known as sunny-day flooding—which occurs without rainfall. In 2023, Norfolk, Virginia experienced 10 days of tidal flooding, but forecasts indicate that by 2075 the area could be experiencing tidal flooding every day. Recent research highlights that even a single tidal flooding event can introduce substantial nutrient loads into the Bay, sometimes exceeding the annual nutrient allocations. This significant increase in both the frequency …

Investigation Of The Effects Of Ocean Acidification On Juvenile Homarus Americanus Feeding Behavior, Sophia Roy

Honors Theses and Capstones

Climate change has led to increased CO2 absorption by ocean surface waters, resulting in decreased pH levels, a phenomenon known as ocean acidification (OA). A primary class of marine organism behavior is impacted by OA, in particular, olfactory-mediated behaviors related to foraging and feeding success. However, the biological mechanisms responsible for the documented impairment of foraging and feeding-related behaviors remains in question. We find that juvenile American lobsters (H. americanus) exhibit significantly faster rates of total feeding times in response to short-term low pH exposure. However, total search time and total handling time were not affected by pH when examined …

Variation In The Fear Response Of Atlantic Sand Fiddler Crabs (Leptuca Pugilator) To Anthropogenic Disturbance, Katrina L. Buttram

Electronic Theses and Dissertations

Leptuca pugilator is a common inhabitant of southeast Georgia salt marshes. This study examined the boldness of Leptuca pugilator across environmental conditions and human impacts. Here, boldness was defined as time taken to reemerge from a burrow after a fear stimulus. I hypothesized that crabs would vary in their boldness based on their surroundings, reproductive timing, and sex. Field and experimental trials were conducted to isolate which factors most influence boldness. Field trials were conducted at four sites varying in human influence throughout the breeding season. During each survey, vegetation height, substrate temperature, average burrow width, burrow count, and distance …

Characterizing The Habitat Use Of Pacific Coast Feeding Group Gray Whales (Eschrichtius Robustus) And The Spatial And Temporal Variability Of Their Benthic And Planktonic Invertebrate Prey In Northern California, Robyn E. Norman

Cal Poly Humboldt theses and projects

As opportunistic foragers, the Eastern North Pacific population (~20,000) of gray whales (Eschrichtius robustus) feed on diverse benthic and planktonic invertebrates in northern Alaska foraging grounds before they undertake one of the largest yearly migrations of any mammal to breed in Baja California, Mexico. While most of the population travels to the summer foraging grounds in Alaska, a sub-group of whales (~230) called the Pacific Coast Feeding Group (PCFG) summer between British Columbia, Canada, and northern California. The diet of PCFG whales typically includes high-density and/or high-caloric prey items like mysids and diverse species of amphipods, yet a …

To Hum Or Not To Hum: Analyzing And Provoking Sound Production In The American Lobster (Homarus Americanus), Renske Kerkhofs

Honors Projects

American lobsters (Homarus americanus) produce humming sounds by vibrating their carapace. These sounds have a fundamental frequency on the order of 100 Hz, with multiple higher harmonics. Though I found no relationship between lobster carapace length and hum frequency, I observed sounds similarly structured to hums but with frequencies an order of magnitude higher, suggesting that lobsters may use a wider range of sounds than previously thought. Using laser vibrometry, I was able to pick up high frequencies of carapace vibration that were similar to those I observed on sound recordings. Lobsters seem to hum most readily when …

Physiological Responses Of The American Lobster Cardiovascular System To Neuropeptide Sgrnflrfamide (Sgrn), Andre Eden

Honors Projects

During every second of a human’s life, the cardiovascular system is modulated by factors both intrinsic and extrinsic to the physiology of the heart. We can uncover new insights regarding the nature of our system through investigations of similar systems in other model species. One example materializes itself in the form of the American Lobster (Homarus americanus) whose single-chambered heart finds resemblance to the function and anatomy to that of humans. The lobster heart is powered by the cardiac ganglion (CG), a group of neurons that drive contractions of surrounding heart muscles, known as the myocardium. Both the …

Mitochondrial Adaptation In The Green Crab Hybrid Zone Of The Gulf Of Maine, Jared Lynch

Honors Projects

The mitochondrial genome has historically been relegated to a neutral genetic marker, but new evidence suggests mitochondrial DNA to be a target for adaptation to environmental stress. The invasive European green crab (Carcinus maenas) exemplifies this in the Gulf of Maine’s hybrid zone, where interbreeding populations exhibit thermal tolerances influenced by mitochondrial genotype. To better understand the mechanism behind this phenomenon, the effect of mitochondrial genotype on mitochondrial activity was tested by measuring mtDNA copy number (mtCN) and the activity of complex I, II, and IV of the electron transport system via high-resolution respirometry. Mitochondria isolated from frozen …

Image Segmentation By Convolutional Neural Networks In Coral Resilience Research, Jennifer Benbow

Master's Projects

As ocean temperatures rise, coral bleaching is becoming more frequent and severe. Selective breeding experiments show promise for enhancing coral resilience, but scaling these projects is hindered by the labor-intensive nature of taking numerous time series measurements as corals grow. Automating this process with computer vision is one solution to this bottleneck, and to our knowledge, no such tool exists at present. To fill this gap, we have trained a set of machine learning models, based on the Mask R-CNN framework, for segmenting juvenile corals in lab-based coral resilience research. This work shows that retraining the Mask R-CNN architecture through …

Habitat Utilization Of Marsh And Adjacent Submerged Landscape By Fish And Macroinvertebrates In A Gulf Of Mexico Tidal Oligohaline Environment, Tia Offner

Theses and Dissertations

Estuarine habitats are considered nursery habitats for fishes and invertebrates, but oligohaline environments are critically understudied. Using a seine net and fyke nets, we sampled Back Bay, Mississippi (USA), a low salinity estuary, once a month for a year to explore the temporal use of the marsh and adjacent submerged landscape by nekton species. We also looked at whether there is evidence of habitat preference in the most numerous nekton species. We used a novel habitat usage index (HUI) to compare seine and fyke net catches of our top 10 species, and evaluated catch size in relation to maturation size. …

Spawning Asynchrony Of The Endangered Acropora Cervicornis: Are Light Pollution And Abnormally Warm Temperatures The Culprits?, Krista Laforest

All HCAS Student Capstones, Theses, and Dissertations

The persistence of reefs relies on mature corals spawning synchronously to maximize fertilization and produce larvae to replenish local populations. Corals synchronize the release of gametes by responding to temperature, sun, and moon light cycles; however, abnormalities in these patterns can disrupt synchrony. This study is the first to describe regional asynchronous spawning of Acropora cervicornis by quantifying gamete development and spawning times among two reefs, an in situ nursery off Fort Lauderdale, and an in situ nursery in the Florida Keys. While A. cervicornis in the Florida Keys synchronously spawned within the predicted window of 2-5 days after the …

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 …

Biophysical Factors Affecting Habitat Suitability For Crassostrea Virginica, Jason D. Tilley

Dissertations

Oyster reefs provide a variety of important ecosystem services. However, the mortality rate of eastern oyster, Crassostrea virginica, the dominant species that produces oyster reefs in the northern Gulf of Mexico, is increasing at an alarming rate due to a variety of abiotic and biological factors. I examined how biophysical factors, including the less-studied fatty acid profiles of the suspended particulate matter on which oysters feed, influenced morphometric condition of C. virginica.

I sampled suspended particulate matter (SPM) and oysters in-situ in the western Mississippi Sound, which historically supported the majority of oyster production in Mississippi waters. Sampling …

Fishing And Fear Effects Interact To Shape Herbivory On Coral Reefs, Bethany M. Tilton

All HCAS Student Capstones, Theses, and Dissertations

Predation influences animal behavior and shapes ecological structure and function through lethal effects and fear effects. On coral reefs, fear effects can alter the distribution and intensity of herbivory by herbivorous reef fishes. This includes the browsing functional group, which potentially reverses macroalgal phase shifts and promotes reef recovery. Herbivory by multiple functional groups may increase on coral reefs through the use of NTZs (no-take zones) but few studies have examined the extent to which small-scale NTZs (< 0.5 km²) influence fear effects and perceived predator presence on reefs. This study aimed to determine whether fear effects on browsers on …

A Rapid Site Selection Assessment As An Indicator Of Stony Coral Microfragment Outplant Success, John J. Alfirevich

All HCAS Student Capstones, Theses, and Dissertations

Microfragmentation of massive stony coral species is a technique being utilized to propagate corals asexually to help restore coral reefs. Microfragmentation consists of cutting corals into 3 cm diameter or less fragments, which boosts growth rates. However, in some locations the size of microfragments make them vulnerable to parrotfish predation and benthic overgrowth, reducing survival. As such, a method to identify key site characteristics which promotes microfragment outplant success, particularly one that can be performed quickly across multiple areas is needed. A rapid site assessment conducted prior to microfragment outplanting was performed at 12 randomly selected sites within the Kristin …

Psammocora Stellata Distribution At Devil's Crown, Floreana Island, Galápagos Islands, Ecuador, María José Guarderas Sevilla

All HCAS Student Capstones, Theses, and Dissertations

In the Galápagos Archipelago, the free-living nodular coral Psammocora stellata is a common species that does not form reef structures. However, it is a key component of the ecosystem by increasing habitat complexity and, consequently, species diversity. This species experienced a drastic decline in Devil’s Crown channel, Floreana Island, where it disappeared after the 1982-83 El Niño-Southern Oscillation, presumably by displacement of unattached colonies by strong surface waves and currents. This assemblage has now recovered to pre-impact levels. A combination of underwater photoquadrats from 2007 and 2009 and recent (2023) orthomosaics were used to determine changes in coral densities and …

Do Mesopelagic Fish Biomass Patterns Change In Response To Major Oceanographic Features In The Northern Gulf Of Mexico?, Ian M. Areford

All HCAS Student Capstones, Theses, and Dissertations

In recent years interest in mesopelagic fishes has grown due to their ecological significance and economic potential. A major outstanding question is how the assemblage is potentially structured by mesoscale (10 - 100s km) oceanographic features such as eddies, fronts, and riverine plumes. Mesoscale features are known to influence micronekton and zooplankton’s spatial distributions but data on individual mesopelagic fish species’ responses are limited. The Gulf of Mexico (GoM) is an area of particular interest due to its diverse mesopelagic fish assemblage, its well-defined mesoscale oceanographic features, its history of anthropogenic impacts such as oil spills, and its diverse mesopelagic …

Interactions Between Sediment Mechanical Structure And Infaunal Community Structure Following Physical Disturbance, William Cyrus Roger Clemo

<strong> Theses and Dissertations </strong>

Shallow, river-influenced coastal sediments are important for global carbon storage and nutrient cycling and provide a habitat for diverse communities of invertebrates (infauna). Elevated bed shear stress from extreme storms can resuspend, transport, and deposit sediments, disrupting the cohesive structure of muds, and sorting and depositing sand eroded from beaches. These physical disruptions can also resuspend or smother infauna, decreasing abundances and changing community structure. Infaunal activities such as burrowing, tube construction, and feeding can impact sediment structure and stability. However, little is known about how physical disturbance impacts short and long-term sediment habitat suitability and whether disturbance-tolerant infauna influence …

The Relationship Between Biofouling Adhesion And Frequency Of Mechanical Cleaning To Control The Recruitment To Clear Coatings, Dylan Thomas Eggers

Theses and Dissertations

There is a need to control biofouling on sensors and transparent windows in the marine environment. Clear silicone coatings offer a method to reduce the adhesion strength of marine organisms to the surface, however, these also require mechanical cleaning to maintain the surfaces free of fouling. This research evaluated the performance of eighty seven formulations and took the top two candidates to investigate a) the frequencies of wiping required by a brush to maintain two coatings and uncoated glass surfaces free of fouling and b) the effects of clear silicone coatings fouling release properties on required frequencies. The panels 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 Short-Term Pesticides Exposure On Swimming Behavior, Tissue Morphology, Oxidative-Nitrative Stress, Antioxidant Expression, And Cellular Apoptosis In Kidneys Of Goldfish, Esmirna Cantú

Theses and Dissertations

The prevalence of pesticides in the aquatic environment continues to increase due to anthropogenic activities and poses a threat to aquatic organisms. The aim of this study was to determine the short-term exposure (one-week) of pesticide mixtures (metolachlor, linuron, isoproturon, tebucanazole, alconifen, atrazine, pendimethalin; azinphos-methyl) on swimming behaviors, kidney morphology, and expression of nitrotyrosine protein (NTP), dinitrophenyl protein (DNP), superoxide dismutase (SOD), catalase (CAT), renin, and cellular apoptosis in goldfish (Carassius auratus). Results indicated that both low- and high-dose pesticide mixtures decreased the distance swimming behavior. Histological analysis showed pesticide exposure alters kidney morphology. DNP, NTP, and renin expressions, and …

An Intersection Of Science & Art: Vitrification Approaches And Open-Fabricated Tools For The Biomedical Model Sea Hare, Aplysia Californica, Allyssa M. Oune

LSU Master's Theses

The California sea hare (Aplysia californica) is an important biomedical model for molecular neurobiology, electrophysiology, learning, and memory due to their well-mapped and large neurons and well-characterized learning capabilities. The National Resource for Aplysia (NRA, University of Miami) maintains large stocks of live animals and relies on regular shipments of wild-caught individuals to maintain genetic diversity. This is labor and cost-intensive, and environmental changes could alter the availability of wild animals increasing the need to preserve this genetic resource. One solution is vitrification, ultra-fast cooling which produces an amorphous glass that minimizes damage to cells. Aplysia californica presents …

Identification Of Biomarkers Of Sub-Lethal Algal Toxin Exposure In Atlantic Salmon (Salmo Salar) And Chinook Salmon (Oncorhynchus Tshawytscha) Using Differential Gene Expression Analysis, Brandon Ellingson

Biology Theses

Atlantic Salmon (Salmo salar) and Chinook Salmon (Oncorhynchus tshawytscha) are important culturally, recreationally, economically, and are a common aquaculture species in Canada and the United States. In the Pacific Northwest, blooms of toxic algae result in millions of dollars annually in losses for salmonid aquaculture producers. Blooms of harmful cyanobacteria produce microcystins which have been linked to net-pen liver disease which has large financial impacts on net pen salmon operations. Microcystin-LR, the most toxic variant, bioaccumulates in the liver and disrupts normal cellular activity by inhibiting protein phosphatases leading to deleterious effects on growth, immune status, and liver function. To …

Population Genomics, Ecology And Conservation Of Asterias Sea Stars In The North Atlantic, Melenia I. Giakoumis

Dissertations, Theses, and Capstone Projects

Uncovering how species respond to environmental change is a central question in biology (Ehrlén & Morris 2015; Habibullah et al. 2022). It is the key to elucidating the past, understanding the present and predicting the future of species’ population dynamics. This dissertation investigates the influence of environmental change on intertidal species’ distributions and genomics at several timescales, with implications for conservation.

Environmental changes have occurred throughout history, on a geological scale, and have shaped the global patterns of species’ distributions and population sizes. Biologists have long studied how geological history has shaped species distributions (Sanmartín 2012) in both terrestrial (Liu …

Predicting Marine Teleost Responses To Ocean Warming And Pollution, Akila Harishchandra

Electronic Theses and Dissertations

Ocean warming and pollution are two detrimental anthropogenic factors causing rapid marine ecosystem degradation recorded in the past decades. These factors alter the marine environment intolerable for many marine species, forcing them to either adapt or shift their contemporary habitat ranges to reduce the extinction risk embedded with environmental degradation. Estimating marine species’ habitat range shifts, and their potential for developing adaptive mechanisms are critical for ecosystem conservation and management, human health risk assessment, and climate change vulnerability assessments. Given that, for the first chapter of this thesis, we focused on developing a species distribution model (SDM) integrating marine species …

Parasites Versus Predation: The Role Of Chronic And Acute Parasite Exposure In Infection Risk And Anti-Predator Behavior, Delaney Farrell

All HCAS Student Capstones, Theses, and Dissertations

Parasites with complex, multi-host lifecycles often engage in host behavior manipulation to increase transmission between successive hosts. In intermediate fish hosts, previous research has measured increased frequency of conspicuous behaviors, decreased swimming performance, and reduced antipredator behavior, which would collectively increase the fish’s risk of predation. In ecosystems where this type of parasite increased trophic transmission (PITT) occurs, parasites can play a substantial role in food webs. In this study, I investigate how chronic versus acute exposure to the trematode Euhaplorchis sp. A. affects the antipredator behavior of the Gulf killifish Fundulus grandis. Using a fully crossed design, I …