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Full-Text Articles in Animal Sciences
Reproductive Investment In Crassostrea Virginica As An Indicator Of A Tolerance Response To Perkinsus Marinus, Lauren Irene Huey
Reproductive Investment In Crassostrea Virginica As An Indicator Of A Tolerance Response To Perkinsus Marinus, Lauren Irene Huey
Dissertations, Theses, and Masters Projects
The Chesapeake Bay region values oysters for the ecosystem services, lucrative fishery, and historical significance that the species embodies; however, over the last half century, oyster abundances have been reduced to historical lows. Two protozoan parasites, Perkinsus marinus and Haplosporidium nelsoni, have been major influences on oyster populations, especially in high-salinity regions. Today, the population is recovering; catches have increased and oysters have expanded spatially. to investigate the cause of the recovery, three measurements were made on slides of oysters from a histological archive collected during summer at Wreck Shoal in the James River from 1988–2017: oocyte diameter, oocyte density, …
The Relationship Between Reproduction And Mortality In Triploid Crassostrea Virginica, Joseph L. Matt
The Relationship Between Reproduction And Mortality In Triploid Crassostrea Virginica, Joseph L. Matt
Dissertations, Theses, and Masters Projects
Unusual mortalities of cultured Crassostrea virginica in late spring have been reported from farms in the Chesapeake Bay from 2014 to 2017. None of the usual causes (e.g. disease, poor husbandry) were likely responsible, and mortalities occurred without clear signs of biological or physical stressors. Mortalities in the spring of 2014 were particularly high on over a dozen farms in Virginia, most of which were on the bayside of the Eastern Shore. Estimated losses were over 50%; however, mortalities only occurred within a four-week period between mid-May and early June. Farmers that had unusually high mortality in their crop were …
The Eastern Oyster Microbiome And Its Implications In The Marine Nitrogen Cycle, Ann Arfken
The Eastern Oyster Microbiome And Its Implications In The Marine Nitrogen Cycle, Ann Arfken
Dissertations, Theses, and Masters Projects
Microbial communities associated with a particular space or habitat, or microbiomes, play significant roles in host health and the regulation of biogeochemical cycles. In oysters these microbiomes may be important contributors in the removal of biologically available nitrogen (N) from the coastal and marine environment through the process of denitrification. Denitrification is the microbially mediated step-wise reduction of nitrate (NO3-) or nitrite (NO2-) to N2 gas. Excess nitrogen in the Chesapeake Bay has been implicated in the increase of eutrophication and other detrimental effects including harmful algal blooms, hypoxia, and loss of benthic communities. Oyster reefs have been shown to …
Individual- And Population-Level Effects Of Temperature And Hypoxia On Two Demersal Fishes In Chesapeake Bay, Benjamin Marcek
Individual- And Population-Level Effects Of Temperature And Hypoxia On Two Demersal Fishes In Chesapeake Bay, Benjamin Marcek
Dissertations, Theses, and Masters Projects
Anthropogenically-induced climate change has resulted in increases in water temperature and the frequency and severity of hypoxic events in coastal areas worldwide. Temperature and hypoxia affect fishes' energetics which can, in turn, be reflected in changes in reproductive success and shifts in spatial distributions. in an effort to quantify these changes in Atlantic croaker (Micropogonias undulatus) and spot (Leiostomus xanthurus) in Chesapeake Bay. I: (1) estimated standard and maximum metabolic rates and hypoxia tolerances at five temperatures (10, 15, 20, 25 and 30°C) using intermittent-flow respirometry, (2) examined the effects of hypoxia exposure on metrics of reproductive potential and, (3) …
Genetic Analyses Of Striped Bass In The Chesapeake Bay: An Investigation Of Connectivity Among Virginia Subestuaries And An Evaluation Of Close-Kinship Mark Recapture Methodology To Estimate Spawning Abundance., Savannah Michaelsen
Dissertations, Theses, and Masters Projects
The striped bass (Morone saxatilis) is an anadromous fish distributed along the eastern coast of North America that currently supports one of the most lucrative and important commercial and recreational fisheries in the region. Since the recovery of the Atlantic stock after a collapse in the late 1970s, studies have focused on understanding the connectivity of major spawning grounds and improving methods of abundance estimation. Studies support strong site fidelity of striped bass to major estuaries along the Atlantic coast, but there has been disagreement about connectivity within the largest spawning ground, the Chesapeake Bay. Additionally, no estimates exist for …
Movements, Habitat Utilization, And Post-Release Survival Of Cobia (Rachycentron Canadum) That Summer In Virginia Waters Determined Using Pop-Up Satellite Archival Tags (Psats), Douglas Jensen
Dissertations, Theses, and Masters Projects
Cobia (Rachycentron canadum) is a cosmopolitan marine fish inhabiting tropical, sub-tropical, and temperate marine and estuarine waters. Recent changes in U.S. cobia management have sparked controversy and highlighted limitations in our understanding of seasonal movement patterns and problems with estimating recreational harvests. Consecutive years (2015 and 2016) of estimated overharvests from the Atlantic Migratory Group stock triggered accountability measures to prevent overfishing by recreational anglers. My project employed pop-up satellite archival tags (PSATs) to study cobia movements, habitat utilization, and post-release survival. It was, therefore, designed to enhance knowledge of cobia biology and aid sustainable management. We deployed 36 PSATs …
Improving Stock Assessments And Management Advice For Bluefin Tunas And Other Highly Migratory Species, Lisa Elma Ailloud
Improving Stock Assessments And Management Advice For Bluefin Tunas And Other Highly Migratory Species, Lisa Elma Ailloud
Dissertations, Theses, and Masters Projects
For years bluefin tuna has been the poster child for overfishing and poor management. However, recent improvements in data collection, catch monitoring and international cooperation are providing an opportunity to reverse the perception of a fishery that is doomed to collapse. Stock assessments are conducted routinely to monitor the abundance and productivity of exploited fish stocks so managers can determine how many fish can be sustainably harvested each year. Should a stock be declared overfished or under-going overfishing, the science behind stock assessments also equip managers with the knowledge necessary to make decisions about what short-term and long-term management measures …
Crab Larval Abundance And Settlement Patterns In A Changing Chesapeake Bay, Itchika Sivaipram
Crab Larval Abundance And Settlement Patterns In A Changing Chesapeake Bay, Itchika Sivaipram
Dissertations, Theses, and Masters Projects
All estuarine crabs have two larval stages, the zoea and the megalopa. Zoeae are entirely planktonic, whereas megalopae begin as plankton before beginning to search for settlement substrates as late stage megalopae. At both stages, crab larvae are subject to environmental conditions of the estuary. With changing environmental conditions due to anthropogenic activities and climate change, an understanding of how these planktonic larvae respond to environmental conditions is necessary for understanding subsequent larval supply to benthic populations and implication for fisheries management and habitat restoration. For this dissertation, I: 1) analyzed long-term timeseries in the lower Chesapeake Bay for spatial …
Multi-Scale Phylogenomics Of Gadiformes With Emphasis On Hakes (Merluccius, Merlucciidae), Adela Y. Roa-Varon
Multi-Scale Phylogenomics Of Gadiformes With Emphasis On Hakes (Merluccius, Merlucciidae), Adela Y. Roa-Varon
Dissertations, Theses, and Masters Projects
Gadiformes include some of the most important commercially harvested fishes in the world (e.g. cods, hakes, and grenadiers). Currently, different authors recognize anywhere between 11 and 14 families, approximately 84 genera, and over 600 species. The monophyly of the order has been supported by both morphological and molecular data, yet the relationships among families and subfamilies remain poorly understood and interpreting phylogenetic patterns to date has been difficult. My dissertation research on multi-scale phylogenetics of Gadiformes with emphasis on hakes (Merluccius, Merlucciidae) has three primary objectives: (1) to improve the understanding of the phylogenetic relationships among families of Gadiformes (Teleostei); …