Aquaculture and Fisheries Commons^™

Population Dynamics Of The Sub-Arctic Copepod Calanus Finmarchicus In The Gulf Of Maine: Demography And Mortality Estimation, Cameron R. S. Thompson

Electronic Theses and Dissertations

Calanus finmarchicus is a widely distributed copepod species that dominants the zooplankton community in the Gulf of Maine. It is of particular interest in its role as a major food source for the endangered northern right whale and stocks of herring, mackerel and cod. More accurate coupled models to predict its distribution requires better life history models. However, due to the difficulty in estimating it, mortality is often used as a closure term in those models; the value is justified mathematically rather than ecologically. Instantaneous mortality is difficult to measure, but the Vertical Life Table method (VLT) has gained some …

Fish Assemblage Dynamics And Red Drum Habitat Selection In Bayou St. John And Associated Urban Waterways Located Within The City Of New Orleans, Louisiana, Patrick W. Smith Mr.

University of New Orleans Theses and Dissertations

Bayou St. John (BSJ) and City Park Lakes and Lagoons (CPLL) are urban waterways in New Orleans, Louisiana. I studied habitat selection of red drum in BSJ, and fish assemblage change in BSJ and CPLL over 40 years. Temperature was found to be the best predictor of red drum habitat selection in Bayou St. John, while salinity and change in depth also were found to be good predictors for certain sites. Potential prey item abundance did not appear to influence habitat selection. Using data from 1971 – 2010, nearshore habitats in CPLL were affected by Hurricane Katrina, but have sense …

An Approach For Use Of Dual Frequency Identification Sonar (Didson) To Quantify Behavioral Aspects Of Piscivory At Ecologically Relevant Time And Space Scales, Victoria E. Price

Master's Theses

Predator-prey interactions of large vagile fishes are difficult to study in the ocean due to limitations in the space and time requirements for observations. Small-scale direct underwater observations by divers (<10m >radius) and large-scale hydroacoustic surveys (10s - 100s km2) are traditional approaches. However, large piscivorous predators identify and attack prey at the scale of meters to tens of meters. Dual- Frequency Identification Sonar, or DIDSON, is a high-resolution acoustic camera operating in the MHz range that provides detailed continuous video-like imaging of objects out to 30 m range. This technology can be used to observe predator-prey interactions at ecologically …

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).

Diversity Of The Ohio River Bacterial Communities Using Next-Generation Sequencing Techniques, Emily Michele Anneken

Theses, Dissertations and Capstones

The ability to sequence bacterial genetic material directly from environmental samples has unlocked the field of metagenomics. Next-generation sequencing techniques, such as pyrosequencing, have been instrumental in providing knowledge about bacterial communities. This study focused on identifying the bacterial diversity of the Ohio River via pyrosequencing and compared the diversity of cultivable bacteria versus the entire river community. To ensure the maximum number of cultivable bacteria was obtained, cultures were grown on nonselective media and incubated at river temperature. Bacterial DNA was extracted, sequenced, and classified. The dominant phyla for the Ohio River included Cyanobacteria (38-66% of the total), Actinobacteria …

Unprecedented Restoration Of A Native Oyster Metapopulation, David M. Schulte

Dissertations, Theses, and Masters Projects

No abstract provided.

Geostatistical Spatiotemporal Modelling With Application To The Western King Prawn Of The Shark Bay Managed Prawn Fishery, Ainslie M. Denham

Theses: Doctorates and Masters

Geostatistical methodology has been employed in the modelling of spatiotemporal data from various scientific fields by viewing the data as realisations of space-time random functions. Traditional geostatistics aims to model the spatial variability of a process so, in order to incorporate a time dimension into a geostatistical model, the fundamental differences between the space and time dimensions must be acknowledged and addressed. The main conceptual viewpoint of geostatistical spatiotemporal modelling identified within the literature views the process as a single random function model utilising a joint space-time covariance function to model the spatiotemporal continuity. Geostatistical space-time modelling has been primarily …