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Development And Validation Of Gene Delivery Methods For ​Crassostrea Virginica, Adrienne N. Tracy Jan 2020

Development And Validation Of Gene Delivery Methods For ​Crassostrea Virginica, Adrienne N. Tracy

Honors Theses

The Eastern oyster (Crassostrea virginica) is an important part of the East Coastal USA economy because aquaculture creates jobs. Sadly, the oysters are under constant threat due to increasing pollution, red tides, and diseases. Bivalves, and oysters in particular, are also becoming potential model organisms in medical research. With the sequencing of the oyster genome, scientists are focusing on deciphering the function of the predicted genes. However, the limited number of molecular and cellular tools available makes functional annotation of the genome challenging. A consistent, replicable gene delivery system needs to be developed to assess gene function and understand the ...


Prospects For The Sustainable Management Of Public Oyster Resources, Thomas M. Soniat, Nathan A. Cooper, Eric N. Powell Aug 2019

Prospects For The Sustainable Management Of Public Oyster Resources, Thomas M. Soniat, Nathan A. Cooper, Eric N. Powell

Faculty Publications

Common-pool resources such as public oyster grounds are especially vulnerable to overexploitation and habitat loss. Like those elsewhere, oyster populations and habitat of Louisiana public grounds are in decline. To maintain reef habitat and increase oyster abundance, a sustainable harvest model is applied, which allows harvest above that required to maintain reef cultch stasis. The model is restrained to promote shell gain by limiting fishing by area, type (sack versus seed), effort, and season. Harvest quotas and cultch removal rates derived from shell-budget–based modeling are a foundation for sustainable management of public oyster resources.


Examining The Effect Of Interstitial Space On Eastern Oysters (Crassostrea Virginica): Applications Of Photogrammetry And Three-Dimensional Modeling, Bailie Lavan May 2019

Examining The Effect Of Interstitial Space On Eastern Oysters (Crassostrea Virginica): Applications Of Photogrammetry And Three-Dimensional Modeling, Bailie Lavan

Masters Theses, 2010-2019

Global oyster populations have decreased by as much as 99% in the past century. Oysters are known ecosystem engineers, providing benthic habitat for macrofauna, linking benthic and pelagic food webs, improving water quality, and mitigating shoreline erosion. Restoration efforts are critical in re-establishing native oyster populations. In the Chesapeake Bay, where oyster loss is primarily due to severe over harvest, artificial substrates with geometric shapes are widely used in restoration efforts. However, natural oyster reefs form emergent shapes with a high degree of aggregation and many interstitial spaces (three-dimensional volumetric spaces between oysters within a reef). The lack of interstitial ...


Comparison Of Nursery Methods To Strengthen Oysters For Aquaculture, Emily M. Combs, Benjamin A. Belgrad, Delbert L. Smee Jan 2019

Comparison Of Nursery Methods To Strengthen Oysters For Aquaculture, Emily M. Combs, Benjamin A. Belgrad, Delbert L. Smee

Gulf and Caribbean Research

No abstract provided.


Tracking Triploid Mortalities Of Eastern Oysters Crassostrea Virginica In The Virginia Portion Of The Chesapeake Bay, Eric Guevelou, Ryan Carnegie, Ja Moss, Karen Hudson, Kimberly S. Reece, Molly M. Rybovich, Standish K. Allen Jr. Jan 2019

Tracking Triploid Mortalities Of Eastern Oysters Crassostrea Virginica In The Virginia Portion Of The Chesapeake Bay, Eric Guevelou, Ryan Carnegie, Ja Moss, Karen Hudson, Kimberly S. Reece, Molly M. Rybovich, Standish K. Allen Jr.

VIMS Articles

Since 2012, aquacultured eastern oysters Crassostrea virginica have been reported by oyster farmers to display mortality approaching 30%, and in some cases 85%, in areas of the lower Chesapeake Bay, VA. Based on accounts from industry, this mortality has typically affected 1-y-old oysters between May and early July, and has tended to occur in triploid oysters, which represent the vast bulk of production in the area. During this period, samples submitted for pathology have not revealed the presence of major pathogens as a cause. In 2015, to gain deeper insight into this mortality and determine whether specific sites, ploidy condition ...


Synergistic Effects Of Temperature And Salinity On The Gene Expression And Physiology Of Crassostrea Virginica, Hollis Jones Oct 2018

Synergistic Effects Of Temperature And Salinity On The Gene Expression And Physiology Of Crassostrea Virginica, Hollis Jones

LSU Master's Theses

Crassostrea virginica, the eastern oyster, forms reefs that provide critical services and benefits to the resiliency of the surrounding ecosystem. Changes in environmental conditions, including salinity and temperature, can dramatically alter the services oysters provide by affecting their population dynamics. Climate warming may further exacerbate the effects of salinity changes as precipitation events increase in frequency, intensity, and duration. Temperature and salinity independently and synergistically influence gene expression and physiology in marine organisms. We used comparative transcriptomics, physiology, and a field assessment experiment to investigate whether Louisianan oyster are changing their phenotypes to cope with increased temperature and salinity stress ...


Analysis Of Temperature And Salinity Effects On Growth And Mortality Of Oysters (Crassostrea Virginica) In Louisiana, Troy Sehlinger Aug 2018

Analysis Of Temperature And Salinity Effects On Growth And Mortality Of Oysters (Crassostrea Virginica) In Louisiana, Troy Sehlinger

University of New Orleans Theses and Dissertations

Salinity (S) and temperature (T) control every facet of the eastern oyster (Crassostrea virginica) life cycle, principally reproduction, development, growth, and mortality. Previous studies conducted in in the Breton Sound (BR) and Barataria (BA) estuaries have reported differences in growth and mortality rates between the basins. In the present study, environmental conditions were synchronized to compare growth and mortality rates between basins at similar combinations of T and S. Results indicate that when T and S are the same (synchronized), seasonal oyster growth and mortality rates differ between BR and BA. Seasonal analyses revealed that as salinities increased in both ...


Caged Oysters Still Get Scared: Predator Presence And Density Influence Growth In Oysters, But Only At Very Close Ranges, Stephen Gosnell J., Kali Spurgin, Erica A. Levine Jan 2017

Caged Oysters Still Get Scared: Predator Presence And Density Influence Growth In Oysters, But Only At Very Close Ranges, Stephen Gosnell J., Kali Spurgin, Erica A. Levine

Publications and Research

Two common forms of variation that may influence consumptive and non-consumptive effects differently are how the biomass of predators is allocated among individual predators (e.g., several small vs few large predators) and how predators are spaced throughout a community. We analyzed how varying the presence, biomass (density, size, and total biomass), and distance to crown conchs (Melongena corona) impacted growth in eastern oysters (Crassostrea virginica) grown in field conditions. The presence of predators decreased growth (new shell added and mass) and increased shell thickness in a 58-day experiment. Although these effects were more pronounced as predator density increased, total ...


Differential Effects Of Bivalves On Sediment Nitrogen Cycling In A Shallow Coastal Bay, Ashley Smyth, Anna E. Murphy, Iris C. Anderson, Bk Song Jan 2017

Differential Effects Of Bivalves On Sediment Nitrogen Cycling In A Shallow Coastal Bay, Ashley Smyth, Anna E. Murphy, Iris C. Anderson, Bk Song

VIMS Articles

In coastal ecosystems, suspension-feeding bivalves can remove nitrogen though uptake and assimilation or enhanced denitrification. Bivalves may also retain nitrogen through increased mineralization and dissimilatory nitrate reduction to ammonium (DNRA). This study investigated the effects of oyster reefs and clam aquaculture on denitrification, DNRA, and nutrient fluxes (NOx, NH4 6 +, O2). Core incubations were conducted seasonally on sediments adjacent to restored oyster reefs (Crassostrea virginica), clam aquaculture beds (Mercenaria mercenaria) which contained live clams, and bare sediments from Smith Island Bay, Virginia, USA. Denitrification was significantly higher at oyster reef sediments and clam aquaculture site than bare sediment in the ...


Quantifying The Success Of Eastern Oyster Pilot Reefs In Brevard County, Florida, Lacie Anderson Jan 2016

Quantifying The Success Of Eastern Oyster Pilot Reefs In Brevard County, Florida, Lacie Anderson

Honors Undergraduate Theses

Crassostrea virginica, the eastern oyster, is a native keystone species that inhabits many coastal and estuarine ecosystems along the Atlantic seaboard. Introduction of the eastern oyster into estuarine areas with limited current populations is gaining popularity as a pro-active approach to improve estuarine water quality. In November 2014 and April 2015, a total of five pilot oyster reef treatments were deployed in Brevard County: bagged adult oysters (grown by community members under their docks through oyster gardening) collected in fall 2014 and spring 2015, bagged clean shell, oyster restoration mats, and empty plots (control). Locations of deployment included a Merritt ...


Natural Cultch Type Influences Habitat Preference And Predation, But Not Survival, In Reef-Associated Species, Erica A. Levine, Stephen Gosnell J., Emily M. Goetz, Christopher R. Malinowski Jan 2016

Natural Cultch Type Influences Habitat Preference And Predation, But Not Survival, In Reef-Associated Species, Erica A. Levine, Stephen Gosnell J., Emily M. Goetz, Christopher R. Malinowski

Publications and Research

A shared origin with fresh and dredged cultch and availability via mining have made fossil cultch a commonly used reef restoration substrate. However, important differences in shape and size between whole-shell cultch and fossil cultch may impact the complexity of reefs constructed from these materials. To determine if these differences may impact the development of restored reefs, we quantified the interstitial space each cultch type provides and constructed reef mesocosms to measure (1) the immediate effects of exposure to each cultch type on mortality of blue crab (Callinectes sapidus) and pink shrimp (Farfantepenaeus duorarum); (2) the tendency of crab, shrimp ...


Estimating Sustainable Harvests Of Eastern Oysters, Crassostrea Virginica, Thomas M. Soniat, Nathan Cooper, Eric N. Powell, John M. Klinck, Mahdi Abdelguerfi, Shengru Tu, Roger Mann, Patrick D. Banks Jan 2014

Estimating Sustainable Harvests Of Eastern Oysters, Crassostrea Virginica, Thomas M. Soniat, Nathan Cooper, Eric N. Powell, John M. Klinck, Mahdi Abdelguerfi, Shengru Tu, Roger Mann, Patrick D. Banks

CCPO Publications

Sustainability of a fishery is traditionally and typically considered achieved if the exploited population does not decline in numbers or biomass over time as a result of fishing relative to biological reference point goals. Oysters, however, exhibit atypical population dynamics compared with many other commercial species. The population dynamics often display extreme natural interannual variation in numbers and biomass, and oysters create their own habitat--the reef itself. With the worldwide decline of oyster reef habitat and the oyster fisheries dependent thereon, the maintenance of shell has received renewed attention as essential to population sustainability. We apply a shell budget model ...


Setting The Sound Up For Success, Hillary Kenyon Oct 2012

Setting The Sound Up For Success, Hillary Kenyon

Wrack Lines

Deploying remotely-set disease-resistant oyster seed in biodegradable netting on a natural bed in Connecticut. The eastern oyster, Crassostrea virginica, is a keystone species in Connecticut's coastal environment.


Understanding The Success And Failure Of Oyster Populations: Periodicities Of Perkinsus Marinus, And Oyster Recruitment, Mortality, And Size, Thomas M. Soniat, John M. Klinck, Eric N. Powell, Eileen E. Hofmann Aug 2012

Understanding The Success And Failure Of Oyster Populations: Periodicities Of Perkinsus Marinus, And Oyster Recruitment, Mortality, And Size, Thomas M. Soniat, John M. Klinck, Eric N. Powell, Eileen E. Hofmann

CCPO Publications

Ten-year time series (1992 to 2002) of salinity, Dermo disease, and size-class structure and mortality measured for an eastern oyster (Crassostrea virginica) population at a reef in Bay Tambour, Terrebonne Parish, LA, were analyzed using wavelet techniques to determine dominant frequencies and correlations. Along the Gulf Coast of the United States, Dermo disease (caused by Perkinsus marinus) responds to the El Nino-Southern Oscillation (ENSO) climate signal through its response to salinity. During the La Nina portion of ENSO, decreased rainfall leads to an increase in salinity, which triggers a rise in Dermo disease prevalence and intensity, producing increased oyster mortality ...


The Rise And Fall Of Crassostrea Virginica Oyster Reefs: The Role Of Disease And Fishing In Their Demise And A Vignette On Their Management, Eric N. Powell, John M. Klinck, Kathryn Ashton-Alcox, Eileen E. Hofmann, Jason Morson Jan 2012

The Rise And Fall Of Crassostrea Virginica Oyster Reefs: The Role Of Disease And Fishing In Their Demise And A Vignette On Their Management, Eric N. Powell, John M. Klinck, Kathryn Ashton-Alcox, Eileen E. Hofmann, Jason Morson

CCPO Publications

We describe a model designed to simulate the shell carbonate budget of an oyster reef.We identify five parameters descriptive of basic characteristics of the shell carbonate budget of a reef that limit simulation accuracy. Two describe the TAZ (taphonomically-active zone) and the distribution of shell carbonate within it. One is the taphonomic rate in the TAZ. Two determine the volume contribution of shell carbonate and the taphonomic loss rate within the reef framework. For Mid-Atlantic estuaries, model simulations suggest that reef accretion only occurs if oyster abundance is near carrying capacity. Simulations further suggest that reef accretion is infeasible ...


Circulation And Water Properties And Their Relationship To The Oyster Disease Msx In Delaware Bay, Zhiren Wang, Dale B. Haidvogel, David Bushek, Susan E. Ford, Eileen E. Hofmann, Eric N. Powell, John Wilkin Jan 2012

Circulation And Water Properties And Their Relationship To The Oyster Disease Msx In Delaware Bay, Zhiren Wang, Dale B. Haidvogel, David Bushek, Susan E. Ford, Eileen E. Hofmann, Eric N. Powell, John Wilkin

CCPO Publications

We apply a high-resolution hydro-dynamical model to investigate the role of physical factors influencing infection prevalence of Haplosporidium nelsoni, causative agent of MSX disease in the eastern oyster (Crassostrea virginica), in Delaware Bay, USA. Validation studies conducted for the years 2000 and 2010-2011 confirm that the model, based upon the Regional Ocean Modeling System, has significant skill in the recovery of observed water level, temperature, salinity, and velocity. Multi-year simulations are performed for periods representing temporal and spatial variations in H. nelsoni infection prevalence (1974-76, 1979-81, 1984-86, 1990-92, and 2006-09) to assess the degree to which the variations in water ...


The Role Of Larval Dispersal In Metapopulation Gene Flow: Local Population Dynamics Matter, Daphne M. Munroe, John M. Klinck, Eileen E. Hofmann, Eric N. Powell Jan 2012

The Role Of Larval Dispersal In Metapopulation Gene Flow: Local Population Dynamics Matter, Daphne M. Munroe, John M. Klinck, Eileen E. Hofmann, Eric N. Powell

OEAS Faculty Publications

The degree of genetic connectivity among populations in a metapopulation has direct consequences for species evolution, development of disease resistance, and capacity of a metapopulation to adapt to climate change. This study used a metapopulation model that integrates population dynamics, dispersal, and genetics within an individual-based model framework to examine the mechanisms and dynamics of genetic connectivity within a metapopulation. The model was parameterized to simulate four populations of oysters (Crassostrea virginica) from Delaware Bay on the mid-Atlantic coast of the United States. Differences among the four populations include a strong spatial gradient in mortality, a spatial gradient in growth ...


Observations Of Distribution, Size, And Sex Ratio Of Mature Blue Crabs, Callinectes Sapidus, From A Chesapeake Bay Tributary In Relation To Oyster Habitat And Environmental Factors, Jm Harding, R Mann Jan 2010

Observations Of Distribution, Size, And Sex Ratio Of Mature Blue Crabs, Callinectes Sapidus, From A Chesapeake Bay Tributary In Relation To Oyster Habitat And Environmental Factors, Jm Harding, R Mann

VIMS Articles

Blue crabs Callinectes sapidus (Rathbun, 1896) > 100 mm carapace width were sampled from a constructed oyster reef (1996 and 1997), a sand bar (1997) and a natural oyster bar (1997) in the Piankatank River, Chesapeake Bay, USA to describe habitat use, sex ratios, and demographics across a gradient of habitat types. Patterns of blue crab catch-per-unit-effort (CPUE), and demographics were similar on the oyster reef in 1996 and 1997. Average annual CPUE on the reef was 6-8 crabs pot(-1) with maximum CPUE of 15 crabs pot(-1). Daylength and water temperature significantly affected reef CPUE with more crabs observed ...


Understanding How Disease And Environment Combine To Structure Resistance In Estuarine Bivalve Populations, Eileen E. Hofmann, David Bushek, Susan E. Ford, Ximing Guo, Dale Haidvogel, Dennis Hedgecock, John M. Klinck, Coren Milbury, Diego Narvaez, Eric Powell, Yongping Wang, Zhiren Wang, Liusuo Zhang Jan 2009

Understanding How Disease And Environment Combine To Structure Resistance In Estuarine Bivalve Populations, Eileen E. Hofmann, David Bushek, Susan E. Ford, Ximing Guo, Dale Haidvogel, Dennis Hedgecock, John M. Klinck, Coren Milbury, Diego Narvaez, Eric Powell, Yongping Wang, Zhiren Wang, Liusuo Zhang

CCPO Publications

Delaware Bay oyster (Crassostrea virginica) populations are influenced by two lethal parasites that cause Dermo and MSX diseases. As part of the US National Science Foundation Ecology of Infectious Diseases initiative, a program developed for Delaware Bay focuses on understanding how oyster population genetics and population dynamics interact with the environment and these parasites to structure he host populations, and how these interactions might modified by climate change. Laboratory and field studies undertaken during this program include identifying genes related to MSX and Dermo disease resistance, potential regions for refugia and the mechanisms that allow them to exist, phenotypic and ...


Modeling The Msx Parasite In Eastern Oyster (Crassostrea Virginica) Populations. Ii. Salinity Effects, Michelle C. Paraso, Susan E. Ford, Eric N. Powell, Eileen E. Hofmann, John M. Klinck Jan 1999

Modeling The Msx Parasite In Eastern Oyster (Crassostrea Virginica) Populations. Ii. Salinity Effects, Michelle C. Paraso, Susan E. Ford, Eric N. Powell, Eileen E. Hofmann, John M. Klinck

CCPO Publications

An oyster population model coupled with a model for Haplosporidium nelsoni, the causative agent of the oyster disease MSX, was used with salinity time-series constructed from Delaware River flow measurements to study environmentally-induced variations in the annual cycle of this disease in Delaware Bay oyster populations. Model simulations for the lower Bay (high salinity) sire reproduced the annual cycle observed in lower Delaware Bay. Simulations at both upper Bay (low salinity) and lower Bay sites produced prevalences and intensities that were consistent with field observations. At all sites, low freshwater discharge resulted in increased disease levels, whereas high freshwater discharge ...


Understanding The Success And Failure Of Oyster Populations: The Importance Of Sampled Variables And Sample Timing, Thomas M. Soniat, Eric N. Powell, Eileen E. Hofmann, John M. Klinck Jan 1998

Understanding The Success And Failure Of Oyster Populations: The Importance Of Sampled Variables And Sample Timing, Thomas M. Soniat, Eric N. Powell, Eileen E. Hofmann, John M. Klinck

CCPO Publications

One of the primary obstacles to understanding why some oyster populations are successful and others are not is the complex interaction of environmental variables with oyster physiology and with such population variables as the rates of recruitment and juvenile mortality. A numerical model is useful in investigating how population structure originates out of this complexity. We have monitored a suite of environmental conditions over an environmental gradient to document the importance of short time-scale variations in such variables as food supply, turbidity, and salinity. Then, using a coupled oyster disease population dynamics model, we examine the need for short rime-scale ...


A Modeling Study Of The Effects Of Size- And Depth-Dependent Predation On Larval Survival, Margaret M. Dekshenieks, Eileen E. Hofmann, John M. Klinck, Eric N. Powell Jan 1997

A Modeling Study Of The Effects Of Size- And Depth-Dependent Predation On Larval Survival, Margaret M. Dekshenieks, Eileen E. Hofmann, John M. Klinck, Eric N. Powell

CCPO Publications

The form of the predation pressure experienced by larval stages of marine invertebrates is largely unknown. However, it is believed that the type, timing and rate of larval predation are critical in determining recruitment to adult populations. In this study, a time and depth-dependent model of the growth and behavior of larvae of the Eastern oyster, Crassostrea virginica, was used to investigate the effects of different forms of size-and depth-dependent predation on larval survivorship. The simulated larval survival for a cohort experiencing size-dependent predation showed that the greatest percent of the cohort survived to competent settlement size when the predation ...


Butyltins In Crassostrea Virginica From Nine Reefs In Mississippi Sound, Thomas F. Lytle, Julia S. Lytle Jan 1997

Butyltins In Crassostrea Virginica From Nine Reefs In Mississippi Sound, Thomas F. Lytle, Julia S. Lytle

Gulf and Caribbean Research

Tributyltin (TBT), a very effective anti-foulant, has been banned from most marine paint uses since 1988 because of its reputed toxicity to nontarget organisms. Crassostrea virginica were collected from nine reefs in the Mississippi Sound in 1993 and analyzed for concentrations of butyltins: TBT, dibutyltin (DBT) and monobutyltin (MBT). TBT concentrations ranged from <2 to >20 ng(Sn)/g wet wt. Highest concentrations of butyltins were found at eastern Sound reefs near intense shipping and ship building activities with lowest concentrations found in the western Sound.


Modeling The Vertical Distribution Of Oyster Larvae In Response To Environmental Conditions, Margaret M. Dekshenieks, Eileen E. Hofmann, John M. Klinck, Eric N. Powell Jan 1996

Modeling The Vertical Distribution Of Oyster Larvae In Response To Environmental Conditions, Margaret M. Dekshenieks, Eileen E. Hofmann, John M. Klinck, Eric N. Powell

CCPO Publications

A size-structured, time and vertically-dependent model was used to investigate the effects of water column structure on the distribution of larvae of the oyster Crassostrea virginica. Formulations used to model larval growth and behavior are based upon laboratory studies. Simulated vertical larval distributions obtained for conditions representative of a well-mixed, partially stratified and strongly stratified water column illustrate the effect that salinity and temperature gradients have on moderating larval swimming and hence on larvae vertical location. For well-mixed conditions, smaller larvae are dispersed throughout most of the water column. For strongly stratified conditions, the smaller-sized larvae cluster within the region ...


A Survey Of Disease In The Oyster Crassostrea Virginica (Gmelin, 1791) In Rhode Island Coastal Estuaries, Retno Andamari, Michael A. Rice, Paul P. Yevich Dec 1995

A Survey Of Disease In The Oyster Crassostrea Virginica (Gmelin, 1791) In Rhode Island Coastal Estuaries, Retno Andamari, Michael A. Rice, Paul P. Yevich

Michael A Rice

The presence of potential pathogens and lesions in American oysters, Crassostrea virginica (Gmelin, 1791), from coastal estuaries in Rhode Island was studied. Oysters were collected by hand or tongs from three stations in the Pawcatuck River, two stations in Narrow River, three stations in Charlestown Pond, and three stations in Green Hill Pond, during July/August 1991, November 1991, March 1992, and May 1992. Oysters were processed for histologic examination and determination of condition index. MSX, Haplosporidium nelsoni (Haskin, Stauber et Mackin, 1966), was detected in four of 480 oysters (0.8%); Sphenophyra sp., 15 of 480 (3.1%); Bucephalus ...


Modeling Oyster Populations Ii. Adult Size And Reproductive Effort, E. E. Hofmann, J. M. Klinck, E. N. Powell, S. Boyles, M. Ellis Jan 1994

Modeling Oyster Populations Ii. Adult Size And Reproductive Effort, E. E. Hofmann, J. M. Klinck, E. N. Powell, S. Boyles, M. Ellis

CCPO Publications

A time-dependent model of energy flow in post-settlement oyster populations is used to examine the factors that influence adult size and reproductive effort in a particular habitat, Galveston Bay, Texas, and in habitats that extend from Laguna Madre, Texas to Chesapeake Bay. The simulated populations show that adult size and reproductive effort are determined by the allocation of net production to somatic or reproductive tissue development and the rate of food acquisition, both of which are temperature dependent. For similar food conditions, increased temperature reduces the allocation of net production to somatic tissue and increases the rate of food acquisition ...


Modeling Oyster Populations. Iv. Rates Of Mortality, Population Crashes, And Management, E. N. Powell, J. M. Klinck, E. E. Hofmann, S. M. Ray Jan 1994

Modeling Oyster Populations. Iv. Rates Of Mortality, Population Crashes, And Management, E. N. Powell, J. M. Klinck, E. E. Hofmann, S. M. Ray

CCPO Publications

A time-dependent energy-flow model was used to examine how mortality affects oyster populations over the latitudinal gradient from Galveston Bay, Texas, to Chesapeake Bay, Virginia. Simulations using different mortality rates showed that mortality is required for market-site oysters to be a component of the population's size-frequency distribution; otherwise a population of stunted individuals results. As mortality extends into the juvenile sizes, the population's size frequency shifts toward the larger sizes. In many cases adults increase despite a decrease in overall population abundance. Simulations, in which the timing of mortality varied, showed that oyster populations are more susceptible to ...


Effect Of Neutral Red Stain On Settlement Ability Of Oyster Pediveligers, Crassostrea Virginica, Patrick Baker Jan 1991

Effect Of Neutral Red Stain On Settlement Ability Of Oyster Pediveligers, Crassostrea Virginica, Patrick Baker

VIMS Articles

The effect of neutral red stain on the settlement of oyster Crassostrea virginica (Gmelin) pediveligers was examined. Larvae were offered two types of substrate: oyster shell and acetate sheets. Settlement was measured as the proportion of pediveligers settled after 24 hours and analyzed with two-factor ANOV A. Staining did not significantly affect settlement, although settlement onto acetate was much lower than onto oyster shell.


Settlement Patterns Of Crassostrea Virginica (Gmelin, 1791) Larvae In Relation To Tidal Zonation, G. Curtis Roegner, Roger L. Mann Jan 1990

Settlement Patterns Of Crassostrea Virginica (Gmelin, 1791) Larvae In Relation To Tidal Zonation, G. Curtis Roegner, Roger L. Mann

VIMS Articles

Experiments were conducted to determine the settlement distribution of the oyster Crassostrea virginica (Gmelin) in relation to tidal zonation in an area where adult populations are largely confined to the intertidal zone. Hatchery-reared pediveliger larvae were interned in PVC tubes positioned at known tidal heights. The influence of non-tidal factors was limited: mesh covering the ends of the tubes prevented loss of larvae to dispersal or predation, the settling substrate was not colonized by competitors, and the effects of light and horizontal currents were minimized. Settlement was found to occur throughout the intertidal zone but predominated at the bottom of ...


Effects Of Inter-Specific Density And Food Supply On Survivorship And Growth Of Newly Settled Benthos, Roman Zajac, Robert B. Whitlatch, Richard W. Osman Aug 1989

Effects Of Inter-Specific Density And Food Supply On Survivorship And Growth Of Newly Settled Benthos, Roman Zajac, Robert B. Whitlatch, Richard W. Osman

Biology and Environmental Science Faculty Publications

Using a laboratory model system comprised of newly settled oysters Crassostrea virginica and established fouling species (Botrylloides sp. initially, and others including Styela clava and Ciona intestinalis as the experiment progressed), we tested how differences in food supply and competitor density may affect post-settlement surivorship and growth of sessile marine invertebrates over a 44 d period. After 15 d, results were mixed but indicated that both food and density conditions affected growth and survivorship significantly, with some suggestion of high food levels ameliorating high density effects However, 44 d after settlement, oysters had reduced survivorship and growth when competitors were ...