Oyster Crassostrea Virginica Research Articles

The Influence of Food Particle Size Distribution on the Success of Eastern Oyster (Crassostrea virginica) Larvae: A Modeling Study

The Influence of Food Particle Size Distribution on the Success of Eastern Oyster (Crassostrea virginica) Larvae: A Modeling Study

Genomic Selection for Dermo Resistance in the Eastern Oyster Crassostrea virginica: Production and Laboratory Testing of F1 Generation

Genomic Selection for Dermo Resistance in the Eastern Oyster Crassostrea virginica: Production and Laboratory Testing of F1 Generation

Investigation of the presence and persistence of bacteria in seawater and oysters from an aquaculture farm in Rehoboth Bay, Delaware.

The filter-feeding nature of oysters, anthropogenic activities, and increasing agriculture in Delaware compromise the microbial safety of Eastern oysters from local aquaculture farms. From July to October 2023, we evaluated the presence and persistence of eight bacteria in seawater and oysters produced from off-bottom and bottom cultures at Sally Cove, an aquaculture farm within Rehoboth Bay in Delaware. A control site within Sally Cove, which was without oyster cultures, was also included in the study. Seawater temperature, salinity, pH, and dissolved oxygen were measured in situ during sampling. Molecular confirmation with PCR and qPCR showed that Vibrio parahaemolyticus, Shiga-toxin-producing Escherichia coli, Salmonella enterica, Staphylococcus aureus, Pseudomonas aeruginosa, and Clostridium spp. were present and persisted in seawater and oyster samples from both cultures at Sally Cove and in off-bottom and bottom seawater samples from the control site throughout the study. Shigella spp. and Listeria monocytogenes were consistently found in seawater and oyster samples from July to September. However, Shigella spp. was only detected in samples from the bottom cultures, whereas L. monocytogenes was undetectable in all samples from both cultures in October. The observed temperature, salinity, pH, and dissolved oxygen levels across the study period were in the range of 15.30-29.67°C, 29.33-31.87 ppt, 7.25-7.95, and 3.79-8.10 mg/L, respectively, and comparable with the conditions suitable for the growth and survival of these bacteria. These findings suggest that consuming raw oysters from Sally Cove poses contamination risks from several bacteria, especially in the summer months.IMPORTANCEAlthough studies have evaluated bacterial contamination in seawater and oysters within the Delaware Inland Bays and nearby areas, the focus has primarily been on Vibrio species. However, other bacteria have been found in seawater and seafood at various locations and could potentially occur in oysters produced from aquaculture farms within the Delaware Inland Bays. Sally Cove is an oyster aquaculture farm that produces Eastern oysters (Crassostrea virginica) for consumption in Delaware using both off-bottom and bottom culturing methods. The risk of bacterial contamination from consuming raw oysters from this farm is unknown. This paper shows the presence and persistence of several bacteria, including those associated with waste, in seawater and oysters at the farm. The findings can inform consumers about the contamination risks from consuming raw oysters produced at the farm.

Polymethylene-Interrupted, Omega-3 and Branched-Chain Fatty Acids and Stable 13C Values of Wild Gulf of Mexico Oysters (Crassostrea virginica) from the Texas Coast.

The complex fatty acid (FA) composition of the edible portion of American oysters (Crassostrea virginica) presents a significant analytical challenge to complete characterization. Here, we employed solvent-mediated covalent adduct chemical ionization to enable comprehensive de novo characterization of its FA composition, with isotope ratio mass spectrometry for initial measurements of FA 13C signatures. Unusual polymethylene-interrupted (PMI) polyunsaturates were unequivocally identified, with 22:2(7Z,15Z) dominating at 5.5% (w/w). In contrast, sea urchins collected from the same area are abundant in shorter-chain-length C20 PMI-FA. Three even-numbered-chain anteiso branched-chain FAs (BCFAs), C14, C16, and C18, were characterized for the first time. Gulf oysters contain 1.8% total BCFA and 23.2% combined EPA and DHA. A 100 g serving of oysters provides 32.9 mg of BCFA; 140.1 mg of PMI-FA; and 426.9 mg of EPA and DHA. Oysters and sea urchins from the same origin exhibit significantly different δ13C values for most measured FA, indicating distinct dietary origins.

Red mangrove (Rhizophora mangle) roots serve as additional valuable habitat for the eastern oyster (Crassostrea virginica) in a subtropical estuary

Red mangrove (Rhizophora mangle) roots serve as additional valuable habitat for the eastern oyster (Crassostrea virginica) in a subtropical estuary

Strain-specific virulence of Perkinsus marinus and related species in Eastern oysters: A comprehensive analysis of immune responses and mortality.

Strain-specific virulence of Perkinsus marinus and related species in Eastern oysters: A comprehensive analysis of immune responses and mortality.

Comparing freshwater mussel responses to stress using life-history and dynamic energy budget theory

Comparing freshwater mussel responses to stress using life-history and dynamic energy budget theory

Modeling larval recruitment dynamics of eastern oysters (Crassostrea virginica) with implications for restoration and management of oyster fisheries

Modeling larval recruitment dynamics of eastern oysters (Crassostrea virginica) with implications for restoration and management of oyster fisheries

The influence of substrate type, elevation, and environmental factors on eastern oysters (Crassostrea virginica) growing on artificial intertidal reefs in Tampa Bay, Florida, USA

The influence of substrate type, elevation, and environmental factors on eastern oysters (Crassostrea virginica) growing on artificial intertidal reefs in Tampa Bay, Florida, USA

Estimation of Growth Performance of Crassostrea virginica in a Recirculating Aquaculture System (RAS) in Cox’s Bazar, Bangladesh: A Case Study

The current study was conducted at the Bangladesh Fisheries Research Institute in Cox’s Bazar, from February 2023 to April 2024. Oyster (Crassostrea virginica) growth and survival rate were studied in a recirculating aquaculture system (RAS). The study also evaluated the impact of various water parameters (viz., temperature, pH, dissolved oxygen [DO], salinity, alkalinity, nitrite, nitrate, and ammonia) on oyster development. Oysters were cultivated in T1, T2, and T3 using two replications for each treatment. RAS was used with continuous aeration throughout the two treatments (T1 and T2), while non‐RAS continuous aeration was given during the control treatment (T3). 50, 60, and 55 oysters were presented in three treatments. Three distinct marine microalgae (Nannochlorum spp., Tetraselmis spp., and Nannochloropsis spp.) were added to tanks for feeding oysters. Statistically significant differences (p < 0.05) were found in the T1 therapy group, which had the highest specific growth rate per day (0.119%) and survival rate (92.85%), followed by T2 (87.5%) and T3 (77.5%). In addition, first treatment (T1) continuously measured the largest weight (36.08 g), length (6.51 cm), and width (6.43 cm); however, T2 showed a significant depth rate (4.44 cm). Optimum oyster population, salinity (29.5 ppt), pH (7.25), DO (5.12), temperature (30.75°C), and other water quality indicator levels displayed a significant correlation with oyster growth performance for the T1 group rather than T2 and T3. However, the T2 group was also treated under RAS circumstances. The findings demonstrated that RAS can significantly enhance oyster growth and survival‐controlling water indicators, which provide valuable insights for sustainable aquaculture practices in the coastal areas of Bangladesh.

Sublethal exposure of eastern oyster Crassostrea virginica to the goniodomin-producing dinoflagellate Alexandrium monilatum: Fate of toxins, histopathology, and gene expression.

The dinoflagellate Alexandrium monilatum forms blooms during summer in tributaries of the lower Chesapeake Bay. Questions persist about the potential for A. monilatum to negatively affect aquatic organisms. Its main toxin, goniodomin A (GDA), a polyketide macrolide, has been shown to have adverse effects on animals, for example through cytotoxicity and interaction with actin. Eastern oysters Crassostrea virginica were exposed for 96 h to sublethal concentrations of A. monilatum (615 ± 47 cells/mL [average ± SD]; containing mainly intracellular GDA [215 ± 7.15 pg/cell]and to a lesser extent goniodomin B, goniodomin C, and GDA seco-acid as quantified by liquid chromatography coupled to tandem mass spectrometry) or to nontoxic phytoplankton or were unexposed. They were subsequently depurated for 96 h by exposure to nontoxic phytoplankton. Clearance rates were estimated, and oysters were sampled daily and tissue (gill, digestive gland, and remaining tissues) excised for analyses by histopathology, gene expression quantified by quantitative PCR, and goniodomin quantification. A positive clearance rate, no mortality, and no tissue pathologies were observed in oysters exposed to A. monilatum. Goniodomin A was detected in gill 6 h after exposure (504 ± 329 μg/kg [average ± SE]) and to a lesser extent in the digestive gland and remaining soft tissues. In the digestive gland, a trend of transformation of GDA to GDA seco-acid was observed. The majority of toxins (≥83%) were depurated after 96 h. Expression of genes involved in oxidative response increased 14-fold after 6 h, and those involved in actin synthesis showed a 27-fold change after 24 h, while expression of apoptosis genes increased 6.9-fold after 96 h compared with the control (eastern oysters exposed to nontoxic phytoplankton). Exposure experiments (nonsublethal or chronic) should be carried out to better assess the threat of this species and toxins for eastern oystersand other marine organisms.

The economic impacts of living habitat changes in the Virginia Middle Peninsula, Chesapeake Bay

The economic impacts of living habitat changes in the Virginia Middle Peninsula, Chesapeake Bay

Assessing the spatial variability of cage movement and velocity attenuation of an off-bottom oyster farm and its influence on eastern oyster (Crassostrea virginica) growth performance

Assessing the spatial variability of cage movement and velocity attenuation of an off-bottom oyster farm and its influence on eastern oyster (Crassostrea virginica) growth performance

Persistent tissue-specific resident microbiota in oysters across a broad geographical range.

Marine animals often harbour complex microbial communities that influence their physiology. However, strong evidence for resident microbiomes in marine bivalves is lacking, despite their contribution to estuarine habitats and coastal economies. We investigated whether marine bivalves harbour stable, resident microorganisms in specific tissues or if their microbiomes primarily consist of transient members reflecting the environmental microbial pool. Conducting a latitudinal study of wild eastern oysters (Crassostrea virginica) along the East Coast of the United States, we aimed to identify resident microorganisms that persist across a wide geographical range. Our results revealed that microbial communities in seawater and sediment samples followed latitudinal diversity patterns driven by geographic location. In contrast, oyster-associated microbiomes were distinct from their surrounding environments and exhibited tissue-specific compositions. Notably, oyster microbiomes showed greater similarity within the same tissue type across different geographic locations than among different tissue types within the same location. This indicates the presence of tissue-specific resident microbes that persist across large geographical ranges. We identified a persistent set of resident microbiome members for each tissue type, with key microbial members consistent across all locations. These findings underscore the oyster host's role in selecting its microbiome and highlight the importance of tissue-specific microbial communities in understanding bivalve-associated microbiomes.

DNA methylation correlates with transcriptional noise in response to elevated pCO2 in the eastern oyster (Crassostrea virginica).

Ocean acidification significantly affects marine calcifiers like oysters, warranting the study of molecular mechanisms like DNA methylation that contribute to adaptive plasticity in response to environmental change. However, a consensus has not been reached on the extent to which methylation modules gene expression, and in turn plasticity, in marine invertebrates. In this study, we investigated the impact of pCO2 on gene expression and DNA methylation in the eastern oyster, Crassostrea virginica. After a 30-day exposure to control (572 ppm) or elevated pCO2 (2827 ppm), whole-genome bisulfite sequencing (WGBS) and RNA-seq data were generated from adult female gonad tissue and male sperm samples. Although differentially methylated loci (DMLs) were identified in females (89) and males (2916), there were no differentially expressed genes and only one differentially expressed transcript in females. However, gene body methylation impacted other forms of gene activity in sperm, such as the maximum number of transcripts expressed per gene and changes in the predominant transcript expressed. Elevated pCO2 exposure increased gene expression variability (transcriptional noise) in males but decreased noise in females, suggesting a sex-specific role of methylation in gene expression regulation. Functional annotation of genes with changes in transcript-level expression or containing DMLs revealed several enriched biological processes potentially involved in elevated pCO2 response, including apoptotic pathways and signal transduction, as well as reproductive functions. Taken together, these results suggest that DNA methylation may regulate gene expression variability to maintain homeostasis in elevated pCO2 conditions and could play a key role in environmental resilience in marine invertebrates.

Model estimation of eastern oyster larval performance from food quantity and quality measures in western Mississippi Sound

Oyster Crassostrea virginica population recovery is critical in degraded estuarine systems, such as Mississippi Sound, USA, where repeated mass mortality events have depleted local oyster stocks. Owing to multiple recent die-offs, the western Mississippi Sound oyster population is recruitment-limited; population growth is constrained by the entry of new individuals into the extant population. Therefore, oyster recovery requires an adequate supply of larvae capable of timely development, growth, and successful metamorphosis. Larval performance and settlement potential are influenced by ambient temperature, salinity, and food supply. Food quantity is important to larvae, but so is food quality, as larvae require a balanced diet of lipids, proteins, and carbohydrates to develop and survive through metamorphosis. In this study, in situ environmental and food conditions during the 2021 and 2022 spawning seasons from 7 oyster reefs in western Mississippi Sound were integrated into an established biochemically based larval performance model to estimate periods facilitative of successful metamorphosis. In 2021, model-estimated larval survivorship was suppressed through much of the spawning season by prolonged, extremely low salinity (<5 ppt) and inadequately balanced food supply. Higher seasonal salinity and more balanced food composition increased model-estimated larval survivorship in 2022, despite lower total food content, suggesting larval performance was primarily governed by the quality of available food. Model-estimated settlement windows were compared to settlement windows derived from concomitant field observations of recruitment. Strong agreement between model-estimated and observed settlement windows validates the effectiveness of the model and informs on the underlying causes of recruitment limitation in western Mississippi Sound.

Habitat-mediated direct and indirect interactions in a marine sedimentary system from Atlantic Canada

Trophic cascades focusing on direct (consumptive) effects have been well studied in marine ecosystems. However, less attention has been given to cascades involving indirect interactions embedded in distinct habitats. We focused on the interactions between a non-indigenous predator (the green crab Carcinus maenas), a consumer (the mud crab Panopeus herbstii), and a prey species (juvenile eastern oysters Crassostrea virginica). These interactions were studied in 3 small yet distinct habitats of increasing complexity: bare sediments, patches of blue mussels Mytilus edulis (BM), and a unique habitat consisting of giant Irish moss Chondrus crispus and mussels combined (IMBM). In the field, green crab predation rates on mud crabs were estimated in each of the abovementioned habitats using tethering experiments. The results showed that green crab foraging was most effective in bare sediments and least effective in IMBM, i.e. the least and most complex habitats, respectively. Trials conducted in the laboratory with mud crabs foraging over oysters showed a similar outcome: oyster mortality rates declined with increased habitat complexity. However, when trials were conducted in the presence of a green crab, this pattern reversed, and oyster mortality was lowest in bare sediments. Mud crab behavior was consistent with these results: in the presence of a green crab, mud crabs were less active and spent more time sheltering, whereas in its absence, the opposite pattern was observed, especially in bare sediments. These behaviorally driven indirect interactions are dependent on the presence of a non-indigenous predator and mediated by the type of habitat.

Triploid eastern oysters (Crassostrea virginica) display high susceptibility to microbial infections but only during early ontogenetic stages

Triploid eastern oysters (Crassostrea virginica) display high susceptibility to microbial infections but only during early ontogenetic stages

Ecological Shifts: Plant Establishment in an Animal-Based Ecosystem

Shifts from saltmarsh to mangroves are well-documented at mangrove poleward boundaries. A regime shift from intertidal oyster (Crassostrea virginica) reefs to mangrove islands has recently been documented in transitional phases in Florida, USA. To understand the local drivers of an oyster/mangrove regime shift and potential tipping points leading to a permanent mangrove state, we tracked all mangrove propagules (n = 1681) across 15 intertidal oyster reefs with or without adult mangroves for 15 months in Mosquito Lagoon, FL. While no propagule bottleneck was observed, few (3.2%) mangrove propagules/seedlings survived on reefs with no prior encroachment, compared to 11.3% and 16.1% on reefs with established older (pre-1943) or newer (1943 to present) adult mangrove stands, respectively. In total, 90.6% of the arriving propagules were from the red mangrove Rhizophora mangle; 13.2% of these were alive at the end of this study. Survival was <1% for black (Avicenna germinans) and 0% for white (Laguncularia racemosa) mangroves. Factors that promoted red mangrove success included close proximity (≤0.3 m) to adult mangroves, especially black mangroves; partial, upright burial of propagules in sediment; and arrival on reefs after annual high-water season. Additionally, once reefs had 50% mangrove cover, the density of red mangrove seedlings increased from 0.04 to 0.46 individuals m−2. Although climate change has alleviated the impact of extreme freezes on mangroves, local factors determine whether the regime shift will be complete and permanent; positive feedback loops associated with established mangroves suggest mangrove recruitment on intertidal oyster reefs will continue to increase.

Hindcasting Estuarine Bottom Salinity Using Observing Systems Data and Nonlinear Regression, as Applied to Oysters in Delaware Bay

Salinity is a major environmental factor that influences the population dynamics of fish and shellfish along coasts and estuaries, yet empirical methods for hindcasting salinity at specific sampling stations are not widely available. The specific aim of this research was to predict the salinity experienced by juvenile and adult oysters (Crassostrea virginica) collected at sampling stations in Delaware Bay. To do so, empirical relationships were created to predict salinity at five oyster bed stations using observing systems data. These relationships were then applied to construct indices of salinity exposure over an oyster’s lifetime. Three independent salinity data sources were used in conjunction with observing systems data to construct and validate the predictive relationships. The root mean square error (RMSE) of the models ranged from 0.5 to 1.6 psu when model predictions were compared with the three independent data sets. Results demonstrated that data from an observing system near the head of Delaware Bay could be used to predict salinity within ± 2 psu at oyster bed stations as far down-estuary as 39 km. When these models were applied to estimate low salinity exposure of 2-year-old oysters via the metric of consecutive days below 5 psu, the indices suggested that there could be as much as a 42-day difference in low salinity exposure for oysters at stations just 31 km apart. The approach of using observing systems data to hindcast salinity could be applied to advance understanding of salt distribution and the effect of low salinity exposure on organisms in other estuaries, especially bottom-associated species.