Digital Commons Network^™

Ecomorphology Of A Predatory Deep-Sea Fish Family: Does Trophic Specialization Drive Hyperspeciation?, Ryan P. Mcgonagle, David Kerstetter, Danté Fenolio, Tracey Sutton

Marine & Environmental Sciences Faculty Articles

Two of the main drivers of speciation among aquatic vertebrates are physical isolation (e.g., lakes and streams) and micro-niche availability (e.g., tropical reefs). In both regards, the mesopelagic domain of the open ocean, Earth’s second largest cumulative ecosystem (behind only the bathypelagic domain), would seem retardant. Ocean circulation makes isolation rare on both contemporary and geological time/space scales, and the lack of substrate precludes stable micro-niches. Paradoxically, some pelagic taxa demonstrate much higher-than-expected species richness on regional scales. A prime example is the dragonfish family Stomiidae, the most speciose family of mesopelagic fishes, owing largely to the subfamily Melanostomiinae (scaleless …

An Ecological Assessment Of The Deep-Pelagic Fish Genus Cyclothone (Gonostomatidae; Stomiiformes), Possibly The World’S Most Abundant Fishes, In The Gulf Of Mexico, Olivia C. North-Menthonnex

All HCAS Student Capstones, Theses, and Dissertations

The fish genus Cyclothone is considered the most abundant vertebrate taxon on Earth. Despite this assertion, very few detailed ecological studies of this genus exist for any site in the World Ocean, largely due to the lack of expertise (and willingness) to identify specimens from existing sample sets. This study will provide a species-level description of the abundance, vertical distribution, and size structuring of the genus Cyclothone in the Gulf of Mexico, a hyper-diverse, deep-pelagic ecosystem that is increasingly impacted by anthropogenic disturbances. As the putative most-abundant fishes in the ecosystem, this characterization is critically needed for a holistic understanding …

Abundance And Distribution Of Fish Larvae In The Central Coast Of The Algerian Sea, Etsouri Mohamed, Khames Ghollame Ellah Yacine, Seridji Rabea

Journal of Marine Science and Technology–Taiwan

This study was conducted on a seasonal basis in five (5) stations along the central Algerian coast between April 2013 and April 2014 aboard professional fishing boats. Horizontal plankton tows with a WP2-type net were used to collect ichthyoplankton samples. At each station, temperature, salinity, and chlorophyll-a levels were measured. We identified the larvae of 18 species from 11 different families by sorting ichthyoplankton (Clupeidae, Engraulidae, Gobidae, Gonostomatidae, Mugilidae, Myctophidae, Scombridae, Sparidae, Carangidae, Labridae, Blennidae). Redundancy analysis (RDA) was used to determine the relationship between the abundance of harvested larvae and environmental variables. The results show a clear dominance of …

Community Ecology And Disease Dynamics In Pacific Oysters: Unraveling Microbiome-Pathogen Interactions In The Wild, Victoria E. Cifelli

Cal Poly Humboldt theses and projects

In the context of multispecies microbial assemblages, disruptions can occur when there are alterations in host conditions, such as the onset of a disease. Notably, viruses have the potential to reshape a host's microbial community. However, the role of the host's habitat and environment, which could be pivotal in communities with shifting niche space and habitat filters, is often overlooked in host-microbe-pathogen interactions. Recognizing the importance of these factors, I employed a field-based approach to understand microbial community dynamics in the presence of disease. To address the influence of geographical location, I conducted an analysis involving healthy and infected oysters …

Larval Ecology Of Atlantic Bluefin Tuna (Thunnus Thynnus): New Insights From Otolith Microstructure, Biotic, And Abiotic Analyses From The Gulf Of Mexico And Mediterranean Sea, Estrella Malca

All HCAS Student Capstones, Theses, and Dissertations

Atlantic bluefin tuna (ABT), Thunnus thynnus, spawn in the Gulf of Mexico (GoM) and the Mediterranean Sea (MED). Spawning occurs within narrow temporal and environmental parameters. Efforts to characterize growth of ABT in wild conditions revealed a wide range of growth variability during the early life stages. This series of studies examined potential biotic and abiotic influences of larval growth from seven ABT cohorts, and identified several key drivers of growth for this commercially valuable species. A detailed investigation of larval dynamics using otolith microstructure was conducted as follows. First, companion growth curves and stable isotope analysis from the same …

Spatial Variation In Hard Bottom Coral Communities Of The Coastal West Florida Shelf, Nicole Blank, Sandra D. Brooke, Brian K. Walker

Marine & Environmental Sciences Faculty Articles

Hard bottom coral and sponge communities differ along portions of the West Florida Shelf (WFS) in species occurrence, diversity, and/or size. However, the composition and spatial distribution of these communities are not well understood. Community transitions have been proposed in the central portion of the WFS around Tampa Bay, Cedar Key, and as far south as Charlotte Harbor, but supporting data are sparse. Fifteen sites in three regions of Florida were surveyed for species distribution, density, and demographics. Distinct communities were found between St Teresa, Hudson, and Tarpon Springs. Coral and sponge densities were highest off Tarpon Springs followed by …

Distribution Patterns Of The Invasive Mussel Arcuatula Senhousia In Mission Bay, San Diego, California: Effects Of Sediment Grain Size And Byssus Thread Production On Predation, Samantha Ahlman

Theses

The ability of bivalves to avoid predation by using defensive behaviors such as burrowing and byssus production may vary depending on the sediment characteristics of a given habitat. The varying sediment characteristics that change with water velocity within estuaries may influence the distribution of bivalves and limit them to areas that optimize their ability to defend against predators. We examined the distribution patterns of the invasive Asian date mussel Arcuatula senhousia relative to the sediment grain size distribution in Mission Bay, an urban estuary located in San Diego, California, USA. Mussels and sediment were collected using an Ekman grab at …

In Situ Observations Of Fish Attraction To Light-Emitting Diodes On An Undersea Observation Deck, Makoto Tomiyasu, Yoko Tanouchi, Yasuzumi Fujimori, Minato Kaji, Takuma Hayashi, Naoto Matsubara, Hiroki Yasuma, Susumu Shimizu, Seiji Katakura

Journal of Marine Science and Technology–Taiwan

Many fisheries employ fishing lights to manipulate the behaviors of target fish and to attract them toward the light; however, relatively few long-time observations of fish attraction have been performed in the field. Here, an underwater observation deck was used to examine the differences in the fish-attracting effect of light-emitting diode (LED) lights on the number of attracted fish and on their behavior in the field, using white-edged rockfish as the target species. A total of 604 ± 324, 307 ± 203 and 171 ± 106 white-edged rockfish individuals were attracted to the observation window when it was illuminated with …

Impacts Of Human Development And Salt Marsh Characteristics On Variation In The Growth And Reproduction Of Spartina Alterniflora, Alora Lovely

Honors Theses

This study focused on how human development may impact salt marshes using the common native species Spartina alterniflora as an indicator. Salt marshes are vital coastal ecosystems that help protect against major flooding and can filter pollutants from the water. Like many environments, salt marshes have been impacted by human development in many ways, from construction of cities and roadways to pollution from industrial facilities and equipment. The salt marshes that once dominated many coastlines along the North American Atlantic coast have been destroyed or reduced in size dramatically with the extensive development that has occurred along these shores. Three …

Spatiotemporal Patterns In The Biomass Of Drift Macroalgae In The Indian River Lagoon, Florida, United States, Lauren M. Hall, Lori J. Morris, Robert H. Chamberlain, M. Dennis Hanisak, Robert W. Virnstein, Richard Paperno, Bernhard Riegl, L. Rex Ellis, Ali Simpson, Charles A. Jacoby

Marine & Environmental Sciences Faculty Articles

Drift macroalgae plays key roles in the ecology of many coastal systems, including the Indian River Lagoon. In the lagoon, changes in the biomass of drift macroalgae may have interacted with an unprecedented bloom of phytoplankton in 2011. Patterns in the biomass of drift macroalgae were identified using new and original analyses of data from several sampling programs collected between 1997 and 2019. All available data show a relatively low biomass of drift macroalgae in 2010–2012, and surveys of fixed transects and seining as part of a fisheries independent monitoring program also recorded low biomass in 2016. Low light availability …

Ecological Risk Assessment For The Western Rock Lobster Resource : Workshop Procedure And Outcomes, R Stoklosa

Fisheries Occasional Publications

No abstract provided.

Kinorhynch Diversity In The Southern Gulf Of Mexico And A Description Of Dracoderes Chaac Sp. Nov., Stephen C. Landers, Kellan Hoffman, Nuria Sanchez, Martin Sorensen

Gulf and Caribbean Research

Sediment collections from the southern Gulf of Mexico between the Texas—Mexico border and the Yucatán Peninsula have resulted in many new kinorhynch species distribution records and the finding and taxonomic description of a new species, Dracoderes chaac sp. nov. This study focused on the non—echinoderid members of the Phylum Kinorhyncha, many of which are rare or restricted to only a few locations. A total of 136 specimens were identified from 24 sediment stations, distributed among the following species: Antygomonas gwenae, Campyloderes vanhoeffeni, Centroderes readae, Condyloderes flosfimbriatus, Co. rohalorum, Cristaphyes panamensis, Dracoderes chaac sp. nov., …

Validation Of The Use Of Clathromorphum Compactum Growth And Skeletal Δ18o As A Proxy For Seawater Conditions, Teagan Mcmahon

Pitzer Senior Theses

Crustose coralline algae (CCA) are important organisms that create benthic habitat in the photic zone of oceans worldwide. CCAs mechanisms of photosynthesis and calcification may, in some cases, make them vulnerable to climate change and ocean acidification. Therefore, CCA are important not only for their ecological role within ecosystems but also for their ability to indicate the effects that ocean acidification and climate change may have on other marine calcifying organisms. Some species of CCA are known to be useful recorders of paleo oceanic conditions. These climate archives and reconstructions of past environmental conditions are important for understanding past changes …

Development Of A Biomass Assessment Method Using Fisheries Echo Sounder For Monitoring Whitebait Fishery In Shizuoka Prefecture, Japan, Kenichi Kobayashi, Yanhui Zhu, Daichi Oshiyama, Kenji Minami, Hokuto Shirakawa, Kazushi Miyashita

Journal of Marine Science and Technology–Taiwan

Coastal fisheries constitute the second most important sector in fishery production in Japan, following offshore fisheries. Thus, spatial evaluation of coastal fishing grounds and understanding of the changes in biomass are important for the sustainable use of fishing resources. For the assessment of spatial fish biomass, a quantitative echo sounder is used, but such a device is not mass produced and involves a high cost. In the present study, we examined the feasibility of biomass assessment using typical commercial fisheries echo sounders that are widely used and cheaper than quantitative echo sounders. Therefore, we aimed to verify the validity of …

Trophic Ecology And Functional Morphology Of The Scaleless Black Dragonfishes (Family Stomiidae; Subfamily Melanostomiinae), Ryan P. Mcgonagle

All HCAS Student Capstones, Theses, and Dissertations

Dragonfishes (Family Stomiidae) are considered the most numerically important and diverse taxon of higher-level meso- and bathypelagic predators in oceanic food webs, with the subfamily Melanostomiinae contributing 220 of the 317 species. The Stomiidae is also the most speciose fish family in the Gulf of Mexico. The relationship between diversity (both systematic and morphological) and feeding of the Melanostomiinae has not been previously examined due to sample size limitation. Here the diet and morphology of 16 species of dragonfishes in the Gulf of Mexico was examined to address the question, “Does the extraordinary speciation in this most-diverse deep-pelagic fish clade …

Otolith Microchemistry Reveals Low Habitat Connectivity Of California Killifish (Fundulus Parvipinnis) Across A Range Of Spatial Scales, Lisa Robison

Theses

As wetlands face continued fragmentation worldwide, an understanding of habitat connectivity and how fishes that rely on these environments is imperative to conduct effective marine management. Site fidelity and habitat connectivity are vital measures of the interdependence of fish populations living in neighboring marshes (or in regions of a single marsh).

Here, we examine the habitat connectivity, site fidelity, and movement of California killifish (Fundulus parvipinnis) within and among three estuaries in Southern California through otolith microelemental analysis. Assessing the site fidelity of estuarine fishes is important to determine the level of connectivity between spatially distinct populations within …

Ontogenetic Variation In Sciaenid Otolith Morphometry With Fish Size From The Northern Gulf Of Mexico, Thomas C. Ingalls

All HCAS Student Capstones, Theses, and Dissertations

Sciaenids are a diverse family of coastal fishes and their fisheries are an important industry in the United States. In the northern Gulf of Mexico this industry is dominated by six species, specifically, red drum (Sciaenops ocellatus), black drum (Pogonias cromis), spotted seatrout (Cynoscion nebulosus), sand seatrout (C. arenarius), Atlantic croaker (Micropogonias undulatus), and spot (Leiostomus xathurus). Sagittal otoliths of all species were evaluated for changes in size and shape in relation to changes in fish total length and age across a variety of seasons and habitats. Evaluation …

Deep-Pelagic Research In The Gulf Of Mexico: Ten Years And Counting…, Tracey Sutton

Marine & Environmental Sciences Faculty Articles

No abstract provided.

Patterns Of Dispersion, Movement And Feeding Of The Sea Urchin Lytechinus Variegatus, And The Potential Implications For Grazing Impact On Live Seagrass, Adrianna Parson, Joseph M. Dirnberger, Troy Mutchler

Gulf and Caribbean Research

The sea urchin Lytechinus variegatus is a known grazer of both living and dead tissue of turtlegrass, Thalassia testudinum, occasionally denuding large areas of seagrass. Field studies have attempted to assess effects of herbivory on seagrass by enclosing urchins at various densities. However, it is unclear how unrestricted urchins affect seagrass at lower densities more typically observed in the field. This study describes movement, feeding, and distribution of L. variegatus within beds of T. testudinum in St. Joseph Bay, Florida (USA) to quantify this urchin’s impact as a seagrass grazer. Urchins were absent from portions of seagrass beds closest to …

Functional Review And Macrostructure Of The Caecum In Ardeidae, Lola R. Mildren

All HCAS Student Capstones, Theses, and Dissertations

Situated on the lower digestive tract, caeca typically project cranially from the juncture of the small and large intestine. Recent studies have proposed that the role of caeca in the avian system is to act as fermentation chambers to synthesize vitamins, modulate gut microflora, and absorb nutrients; however, functionality differs with diet. Caeca are a typical characteristic of the avian gastrointestinal tract, with varying sizes and shapes, or even rudimentary or absent in some species. Caeca are notably singular and relatively small in Ardeids. Morphometric consistency in the number and presence of caeca on the lower intestinal tract of Ardeids …

The Roles Of Host Species, Geographic Scale And Environmental Stressors In Shaping The Composition Of Coral Microbiomes, Alicia Marie Riegel Parker

LSU Doctoral Dissertations

Reef-building corals are long-lived and may take many centuries to adapt, making them especially susceptible to climate change. However, corals host microbial symbionts that can change quickly, potentially speeding acclimation. My dissertation aimed to determine the degree of coevolution and flexibility between corals and their microbiomes among hosts, across space, and in response to stress.

Microbial communities are usually surveyed by sequencing the 16S rRNA gene, however the PCR primers used also amplify coral DNA, thereby limiting prokaryotic read coverage. To mitigate this contamination, I designed a peptide nucleic acid clamp that increased the recovery of bacterial reads by 2-11x …

A Shark Conservationists Toolbox: Current Dna Methods And Techniques Aiding In The Conservation Of Sharks, Arianna N. Nixon

All HCAS Student Capstones, Theses, and Dissertations

Elasmobranchs are important members of their community. Many sharks are important apex predators that help maintain the health of their ecosystem. However, shark populations are globally declining. This is partially due to the fact that sharks are highly targeted for their fins, meat, liver oil, teeth, and skin. However, they are also killed from anthropogenic effects such as habitat destruction and pollution. Most shark species have life history characteristics that also make them more vulnerable to overfishing. Sharks are also difficult to study due to their elusive nature and identification issues. That is why molecular tools are increasingly becoming important …

Insights To Gray Seal (Halichoerus Grypus) Foraging Ecology From Stable Isotope And Dna Metabarcoding Analyses, Keith Michael Hernandez

LSU Doctoral Dissertations

The enactment of wide-ranging conservation laws in the United States enabled the recovery of many marine mammal species. However, as many species have surpassed predicted recovery goals, there is an increasing number of marine mammal-human interactions. For example, in the northeast US, the recovery of gray seals (Halichoerus grypus atlantica), coupled with declines in commercially important fishery species, has prompted discussions of revised management, and potentially lethal control measures. Much of this concern stems from seal-fisheries interactions, which necessitates an understanding of seal diets and foraging ecology. However, existing research is out of date and reliant primarily on …

Changes In Reef Fish Community Structure Following The Deepwater Horizon Oil Spill, Justin P. Lewis, Joseph H. Tarnecki, Steven B. Garner, David D. Chagaris, William F. Patterson Iii

C-IMAGE Publications

Large-scale anthropogenic disturbances can have direct and indirect effects on marine communities, with direct effects often taking the form of widespread injury or mortality and indirect effects manifesting as changes in food web structure. Here, we report a time series that captures both direct and indirect effects of the Deepwater Horizon Oil Spill (DWH) on northern Gulf of Mexico (nGoM) reef fish communities. We observed significant changes in community structure immediately following the DWH, with a 38% decline in species richness and 26% decline in Shannon-Weiner diversity. Initial shifts were driven by widespread declines across a range of trophic guilds, …

Reproductive Ecology Of Dragonfishes (Stomiiformes: Stomiidae) In The Gulf Of Mexico, Alex Marks, David Kerstetter, David Wyanski, Tracey Sutton

Marine & Environmental Sciences Faculty Articles

The most abundant fishes on Earth live in the meso- and bathypelagic (deep-pelagic, collectively) zones of the open ocean, where they play a key role in deep-sea food webs by mediating energy flow from surface waters to great depth. Of these fishes, the most speciose taxon is the family Stomiidae (dragonfishes). Despite being the numerically dominant predators of the global mesopelagic zone, stomiid reproductive ecology is poorly known. Research surveys rarely catch larger adults, impeding reproductive ecology studies. Between 2010 and 2011, the Offshore Nekton Sampling and Analysis Program sampled the Gulf of Mexico using a research-sized, opening/closing trawl (10-m …

Evolutionary Traits That Enable Scleractinian Corals To Survive Mass Extinction Events, Gal Dishon, Michal Grossowicz, Michael Krom, Gilad Guy, David F. Gruber, Dan Tchernov

Publications and Research

Scleractinian “stony” corals are major habitat engineers, whose skeletons form the framework for the highly diverse, yet increasingly threatened, coral reef ecosystem. Fossil coral skeletons also present a rich record that enables paleontological analysis of coral origins, tracing them back to the Triassic (~241 Myr). While numerous invertebrate lineages were eradicated at the last major mass extinction boundary, the Cretaceous-Tertiary/K-T (66 Myr), a number of Scleractinian corals survived. We review this history and assess traits correlated with K-T mass extinction survival. Disaster-related “survival” traits that emerged from our analysis are: (1) deep water residing (>100 m); (2) cosmopolitan distributions, …

The First Global Deep-Sea Stable Isotope Assessment Reveals The Unique Trophic Ecology Of Vampire Squid Vampyroteuthis Infernalis (Cephalopoda), A. V. Golikov, F. R. Ceia, R. M. Sabirov, J. D. Ablett, Ian G. Gleadall, Gudmundur Gudmundsson, Henk-Jan T. Hoving, Heather L. Judkins

USF St. Petersburg Campus Faculty Publications

Vampyroteuthis infernalis Chun, 1903, is a widely distributed deepwater cephalopod with unique morphology and phylogenetic position. We assessed its habitat and trophic ecology on a global scale via stable isotope analyses of a unique collection of beaks from 104 specimens from the Atlantic, Pacific and Indian Oceans. Cephalopods typically are active predators occupying a high trophic level (TL) and exhibit an ontogenetic increase in δ15N and TL. Our results, presenting the first global comparison for a deep-sea invertebrate, demonstrate that V. infernalis has an ontogenetic decrease in δ15N and TL, coupled with niche broadening. Juveniles are mobile zooplanktivores, while larger …

Abundance And Occurrence Of Common Bottlenose Dolphins (Tursiops Truncatus) In Three Estuaries Of The Northwestern Gulf Of Mexico, Errol Ronje, Heidi Whitehead, Kevin Barry, Sarah Piwetz, Juliane Struve, Vincent Lecours, Lance Garrison, Randall S. Wells, Keith D. Mullin

Gulf and Caribbean Research

Current abundance estimates for populations of common bottlenose dolphins (Tursiops truncatus, Montagu, 1821) in bays, sounds, and estuaries are lacking throughout most of the northwestern Gulf of Mexico, including areas of Texas and western Louisiana. To address this issue, we conducted 92 small-boat photographic identification surveys covering ~2000 km² and comprising ~11,000 km of track-line in winter and summer seasons in West Bay, TX (2014 – 2015, n = 25), the Galveston Bay, TX system (2016, n = 50), Sabine Lake, TX (2017, n = 17), and adjacent coastal waters. Individual dolphin encounter histories were constrained by …

Spatio-Temporal Models Of Juvenile And Adult Sheepshead (Archosargus Probatocephalus) In Tampa Bay, Florida From 1996 To 2016, Bridgette F. Froeschke, Leslie B. Jones, Brian Garman

Gulf and Caribbean Research

Spatio-temporal distribution models for juvenile and adult Sheepshead (Archosargus protocephalus) were developed for Tampa Bay, FL using Boosted Regression Trees. Juvenile Sheepshead were primarily associated with month of collection (highest occurrence in May and June), low salinities (<10), and increased distance from a tidal inlet. Adult Sheepshead were more frequently detected closer to inlets in September through November, with an increasing trend through time, and had the highest probability of detection in areas with the highest salinity levels. Our results indicate that juvenile Sheepshead are associated with tidal tributaries on the east side of Tampa Bay and adult Sheepshead are associated with the major inlet into the Gulf of Mexico. These findings reflect seasonal and ontogenetic shifts in distribution that are necessary to inform spatially-based management approaches and to prioritize areas for habitat conservation.

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 …