Ecology and Evolutionary Biology Commons^™

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 …

Population Structure, Connectivity, And Phylogeography Of Two Balistidae With High Potential For Larval Dispersal: Balistes Capriscus And Balistes Vetula, Luca Antoni

Dissertations

The gray triggerfish (Balistes capriscus) and the queen triggerfish (Balistes vetula) are two exploited reef fish distributed in tropical and temperate shelf waters of the Atlantic Ocean and the Mediterranean Sea. Both species are highly sedentary as adults but disperse pelagic larvae for extended periods of time potentially allowing connectivity across long distances under the action of oceanic currents. In this work population structure, phylogeography, and migration patterns were examined in the two species and contrasted with predictions of larval transport based on surface circulation data. A total of 1,017 gray triggerfish from twelve sampling localities …

Bloom Or Bust: Retrospective Analysis Of The Giant Jellyfish, Nemopilema Nomurai (Scyphozoa: Rhizostomeae), Ecology In The East Asian Marginal Seas, Naomi Yoder

Master's Theses

The Giant Jellyfish, Nemopilema nomurai, is a large-bodied bloom-forming jellyfish that occurs in the semi-enclosed basins of the East Asian Marginal Seas. N. nomurai has bloomed more frequently in the past 20 years than in any period previously recorded. In Japan, recent N. nomurai blooms were responsible for millions of dollars in lost revenue and equipment damage to commercial fisheries alone. This study statistically analyzed 21 environmental factors in connection with N. nomurai occurrence (using occurrence as a proxy for blooms). Eight factors resulted in a statistically significant or marginally significant (p ≤ 0.10), linear or non-linear relationship with …

Development Of Genomic Resources For The Evaluation Of Red Snapper, An Emerging Species Candidate For Marine Aquaculture And Stock Enhancement, Adrienne Elise Norrell

Master's Theses

The northern red snapper (Lutjanus campechanus) is a highly targeted reef fish candidate for marine aquaculture and stock enhancement in the southern United States. This work aimed to develop genomic resources for the genetic management of aquaculture programs and to investigate population structure using high-throughput sequencing technologies. Eighty-four new microsatellite markers were developed through screening of Illumina paired-end sequencing reads. Microsatellite loci and Single Nucleotide Polymorphisms (SNPs) generated through Restriction Site Associated DNA (RAD) sequencing were assayed in 5 outbred full-sib families to construct a high-density linkage map of the red snapper genome. The map consists of 7,964 …

Effects Of Pre-Release Physical Stressors On Post-Release Success Of Hatchery-Reared Spotted Seatrout, Taylor Westbrook Guest

Master's Theses

Alteration of habitat associated with coastal development and increased demand for food and recreation can result in the depletion of fisheries resources such as the Spotted Seatrout (Cynoscion nebulosus), the Gulf of Mexico’s most popular recreational fish. Stock enhancement, or the release of cultured fish to supplement wild populations, is one potential tool for managing important fisheries resources. Although much effort has gone into marine stock enhancement, the effectiveness of stocking is not well established, and techniques for ensuring success have not been developed. Although the basic biology of the Spotted Seatrout is well known, comparatively little is known about …

Genetic Variation In Potentially Virulent Vibrio Parahaemolyticus From The Northern Gulf Of Mexico, Nicholas Felix Noriea Iii

Dissertations

Vibrio parahaemolyticus (V_p) is a gram-negative bacterium found naturally in marine and estuarine environments. V_p is found in oysters including those which are later consumed by the public. Sub-populations of potentially virulent Vp contain specific virulence factors and are relevant human pathogens capable of causing gastroenteritis, wound infection, and death. The tdh and trh genes, both encoding hemolysins, have been correlated with the majority of clinical V_p isolates but have not been shown to be the definitive virulence factors.

A total of 146 V_p isolates from the northern Gulf of Mexico were collected and probed …

Effects Of Hypoxia And 4-Tert-Octylphenol On Gene Expression Profiles Of The Sheepshead Minnow (Cyprinodon Variegatus), Arthur Alan Karels

Dissertations

Hypoxia occurs in estuaries of northern Gulf of Mexico and world-wide, with increasing frequency/severity via eutrophication and anthropogenic influences. Hypoxia inducible factors (HIFs) form transcriptional complex and bind DNA at hypoxia responsive elements (HREs) in promoter regions of genes needed for systemic and cellular adaptation of fish to low dissolved oxygen (hypoxia, DO <2.0 mg/ml). Hypoxia-induced activation of HIF-αs can lead to a cascade of downstream activation, such as erythropoietin (EPO). Return to normal DO levels (normoxia), prolyl hydroxylases (PHDs) are activated to degrade HIF-αs back to baseline. Fish are affected by environmental estrogen mimics, like 4-tert-octylphenol (4tOP), binding estrogen receptor alpha (ERα) at estrogen responsive elements (EREs) and activating genes vitellogenin (VTG). Previous research showed overlap or crosstalk between these two mechanistic pathways. Hypoxia triggers unknown factors regulating ERE-mediated ERα signaling pathway, and stressor combinations could increase/decrease hypoxic or endocrine pathway. Research examined molecular/physiological effects of hypoxia (acute and chronic, moderate and severe) and 4tOP (~60μg/L)on adult male and/or female sheepshead minnow (Cyprinodon variegatus). Three genes identified, cloned, and sequenced (HIF-1α, HIF-2α, and PHD3), plus previously identified genes EPO and VTG, were examined in liver/testes exposed to hypoxia and/or 4tOP for cellular/physiological changes. Endpoints examined included mRNA expression from real-time PCR of HIF-1α, HIF-2α, PHD3, EPO, and VTG using cDNA from total RNA extracts, and microarray analyses of genes expressed during the transition from hypoxia back to normoxia. Phylogenetic analyses confirmed isolation of two HIF-α isofoms (HIF-1α and HIF-2α) and the PHD3 isoform. Significant up-regulation of PHD3 occurred within 10 hrs of chronic hypoxia, and persisted when severe (1.5 mg/L) and declined when moderate (~2.5mg/L). Significant up-regulation of HIF-1α and EPO occurred within 30 minutes to 2 hours of onset of acute severe and very severe (~1.08mg/L) hypoxia. Hypoxia acted similar to an estrogen mimic, with huge up-regulation of VTG gene expression in males, and increased VTG levels (additive effect) when hypoxia was combined with 4tOP. Microarray analyses showed 125 genes with significant transcriptional change, with up- or down-regulation from transitions of: (1) hypoxia (72 hrs) to normoxia (74 hrs) and (2) hypoxia+4tOP (72 hrs) to normoxia+4tOP (74 hrs).