Aquaculture and Fisheries Commons^™

Is Temperature, Dissolved Oxygen, Or Salinity Driving Oyster Mortality On Breakwaters?, Ashten Notz, Aaron Bland, Ronald Baker

Gulf and Caribbean Research

No abstract provided.

Genome-Wide Analysis Of Acute Low Salinity Tolerance In The Eastern Oyster Crassostrea Virginica And Potential Of Genomic Selection For Trait Improvement, Alexandra J. Mccarty, Standish K. Allen Jr., Louis V. Plough

VIMS Articles

As the global demand for seafood increases, research into the genetic basis of traits that can increase aquaculture production is critical. The eastern oyster (Crassostrea virginica) is an important aquaculture species along the Atlantic and Gulf Coasts of the United States, but increases in heavy rainfall events expose oysters to acute low salinity conditions, which negatively impact production. Low salinity survival is known to be a moderately heritable trait, but the genetic architecture underlying this trait is still poorly understood. In this study, we used ddRAD sequencing to generate genome-wide single-nucleotide polymorphism (SNP) data for four F_{2 …}

Effects Of Salinity On Eastern Oysters: Locating Lower-Salinity Tolerant Populations And Defining Resource Zones Suitable To Restoration, Fisheries, And Aquaculture., Lauren Swam

LSU Master's Theses

Eastern oysters (Crassostrea virginica) provide valuable ecosystem services and support a productive commercial industry in the northern Gulf of Mexico. Declining abundance from water quality changes and other factors drives development of management and restoration strategies focused on a comprehensive, metapopulation approach. Identifying oyster resource zones based on water quality combined with selective breeding of oysters adapted to specific conditions provides strategies to support aquaculture development and ensure resilient oyster populations and high production. Using 2015-2019 satellite-derived continuous salinity and temperature data for coastal Louisiana, this work created maps defining oyster resource zones supportive of (1) broodstock sanctuary …

Multiple Drivers Of Interannual Oyster Settlement And Recruitment In The Lower Chesapeake Bay, Brendan Turley, Kimberly S. Reece, Jian Shen, Jeong-Ho Lee, Ximing Guo, Jan Mcdowell

VIMS Articles

Despite global investment in shellfish restoration activities, relatively little attention has been given to predicting optimal restoration sites and testing these expectations. We used a coupled biological-physical connectivity model as a guide to plant two distinct hatchery-spawned strains of the eastern oyster, Crassostrea virginica, in the Lafayette River, Virginia during the summer of 2013 at two locations corresponding to virtual spawning locations within the connectivity model. We utilized single nucleotide polymorphism markers to test the model predictions by genotyping oysters recruited after planting two hatchery-spawned strains and examining interannual recruitment variability for two successive years. Two spat were identified …

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, …

The Impact Of Co2-Related Ocean Acidification On The Molecular Regulation Of Shell Development In The Eastern Oyster (Crassostrea Virginica)., Mackenzie L. Richards

LSU Master's Theses

Eastern oysters (Crassostrea virginica), native to the Gulf of Mexico, are keystone species in estuarine ecosystems and are economically valued. Current research indicates that ocean acidification adversely affects the physiology and morphology of larval oysters, but the molecular mechanisms of this impact remain unstudied. Ocean acidification is contributed to by elevated atmospheric CO₂ due to increased anthropogenic activities, causing heightened partial pressure of CO₂ (pCO₂), and eutrophication from land-based runoff in the Gulf. The objective of this work was to determine the genomic response of the eastern oyster in Louisiana to simulated ocean acidification. …

Maine's Oyster Renaissance, Catherine Schmitt

Catherine Schmitt

This feature article in Maine Food & Lifestyle magazine profiles Eric Horne and Valy Steverlynk, proprietors of Flying Point Oysters in Freeport, Maine.

Maine Oyster Cult, Catherine V. Schmitt

Catherine Schmitt

Read about the natural history of Maine's oyster populations, and how the University of Maine and independent aquaculturists have brought these native shellfish back to coastal waters--and tables--in Maine. This story appeared in the March 2008 issue of Maine Boats, Homes, & Harbors magazine.

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 for …

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 in late …

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 …

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 …

Modeling Diseased Oyster Populations. Ii. Triggering Mechanisms For Perkinsus Marinus Epizootics, Eric N. Powell, John M. Klinck, Eileen E. Hofmann

CCPO Publications

Densities of Crassostrea virginica remain high enough to support substantial fisheries throughout the Gulf of Mexico despite high mortality rates produced by the endoparasite Perkinsus marinus. The infrequency of epizootics in these populations suggests that controls exist on the disease intensification process. The progression of epizootics in oyster populations, the factors that trigger epizootics, and the factors that terminate epizootics once started were investigated with a coupled oyster population—P. marinus model.

The time development of a simulated epizootic was triggered by environmental conditions that occurred and disappeared as much as t8 months prior to the onset of mortality in …

Shell Disease In The Gold Lip Pearl Oyster, Pinctada Maxima And The Eastern Oyster, Crassostrea Virginica, Frank O. Perkins

VIMS Articles

A description is provided of the anomalous conchiolin deposits which are formed by Pinctada maxima and which are associated with unusual morta]jties. Comparisons are made with brown ring disease found in Ruditapes philippinarum and juvenile Crassostrea virg inica. In P. maxima, the deposits are not organized into a ring but rather a.re broad-based and result in retraction of the mantle with the deposits lying outside the edge of the mantle. Vibrio sp. have been implicated in causing the di seases of P. max ima and R. philippinarum whereas the etiological agent of the disease in C. virginica is unknown. It …

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 sp. 16of 480 …

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

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 population declines …

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.

Recruitment And Growth Of Oysters On Shell Planted At Four Monthly Intervals In The Lower Potomac River, Maryland, Reinaldo Morales-Alamo, Roger L. Mann

VIMS Articles

Oyster shells were planted on four successive months (May to August 1986) in contiguous plots at Jones Shore Bar in the Potomac River, Maryland, to study the effect of differences in time of cultch planting on settlement and survival of oyster spat. The plots were usually sampled at two-week intervals from time of planting through November, 1986, and once in June, 1987. A massive concentration of the tunicate Molgula manhattensis covered the bottom in all plots within four to six or eight weeks following shell planting. A commercially acceptable number of spat per shell, between 1.8 and 2.2 (approximately equivalent …

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 …

Effect Of Decreasing Oxygen Tension Of Swimming Rate Of Crassostrea Virginica (Gmelin, 1791) Larvae, Roger L. Mann, Julia S. Rainer

VIMS Articles

Four sizes of Crassostrea virginica Gmelin larvae (mean lengths 76.8, 118.1, 139.7 and 290.2 [Lm) were exposed to ·stepwise decreases in oxygen concentration from I 00% saturation (5 .38 mill at 22°C and 22 ppt salinity) to as low as 10% saturation and their swimming rates (net vertical movement per unit time) were recorded at each oxygen concentration. No cessation of swimming was observed and in only two conditions, that of 76.8 [Lm larvae at 10% saturation and 290.2 j.Lm larvae at 21% saturation, was swimming rate significantly lower than that of the same size larvae at full saturation.

Anatomical Features In Histological Sections Of Crassostrea Virginica (Gmelin, 1791) As An Aid In Management Of Gonad Area For Reproductive Assessment, Reinaldo Morales-Alamo, Roger L. Mann

VIMS Articles

The relationship between gonad area in transverse histological sections of the American oyster Crassostrea virginica (Gmelin 1790) and body location from which the section was cut was studied in specimens collected from four stations in the James River, Virginia in 1984 and 1986. Gonad area, expressed as percentage of total body area, increases in an antero-posterior direction; this requires use of sections from the same body location in comparisons between oysters. Approximate body locations, identified according to the anatomy and arrangement of the internal organs in the sections, were grouped into five types with similar gonad area percentages. One of …

Predation On Single Spat Oysters Crassostrea Virginica (Gmelin) By Blue Crabs Callinectes Sapidus Rathbun And Mud Crabs Panopeus Herbstii Milne-Edwards, Robert Bisker, Michael Castagna

VIMS Articles

Single spat oysters Crassostrea virginica of four size classes (3.4-24.6 mm mean shell heights [SH]) were offered to six size classes of blue crabs Ca/linectes sapidus (9.3-85.5 mm mean carapace width [CW]) and five size classes of mud crabs Panopeus herbstii (7.1-34.4 mm mean CW) for 48 hr. Predation rate, recorded as the number of dead oyster spat/crab/day, was directly proportional to crab size and inversely proportional to oyster size. Mud crabs of 34.4 mm CW and blue crabs of 85 .5 mm CW had predation rates of 22.5 and 16.7 spat/crab/day on oyster spat of 24.6 and 24.4 mm …