Search

Aquatic environments are important sources of healthy and nutritious foods; however, clams, mussels, and oysters (the bivalves most consumed by humans) can pose considerable health risks to consumers if contaminated by heavy metals in polluted areas. These organisms can accumulate dangerously high concentrations of heavy metals (e.g., Cd, Hg, Pb) in their soft tissues that can then be transferred to humans following ingestion. Monitoring contaminants in clams, mussels and oysters and their environments is critically important for global human health and food security, which requires reliable measurement of heavy-metal concentrations in the soft tissues. The aim of our present paper is to provide a review of how heavy metals are quantified in clams, mussels, and oysters. We do this by evaluating sample-preparation methods (i.e., tissue digestion / extraction and analyte preconcentration) and instrumental techniques (i.e., atomic, fluorescence and mass spectrometric methods, chromatography, neutron activation analysis and electrochemical sensors) that have been applied for this purpose to date. Application of these methods, their advantages, limitations, challenges and expected future directions are discussed. [ABSTRACT FROM AUTHOR]

Vibrio spp. are ubiquitous bacteria that are frequently discovered in aquatic environments. Globally, they are recognized as the primary cause of seafood-related illnesses. Over decades, vibrios have been a major health concern, and the number of cases is on the rise due to unhygienic eating habits and increasing demand for raw seafood. Among the 2 groups of Vibrio bacteria, the non-cholera Vibrio bacteria group mainly associate with seafood-borne illness. Though ~ 12 species have been recognized as causative agents of diseases in humans, horizontal gene transfer has attributed to an increase in emerging human pathogenic Vibrio spp. The assortment of virulence determinants contributes to the pathogenicity of vibrios. They carry specific genes to produce toxins and hemolysin, which are correlated with pathogenicity. In addition, the expanding antimicrobial use in humans and aquaculture resulted in a surge of resistant Vibrio strains found in shellfish. This has adversely affected the therapeutic results in the case of Vibrio infection. Thus, this article provides insight into the potential public health threat that may pose to seafood consumers as a consequence of the presence of virulence factors and antimicrobial resistance determinants in molluscan shellfish-borne vibrios. [ABSTRACT FROM AUTHOR]

Production by macrofauna associated with oyster reefs offers a multi-purpose indicator of ecosystem function, ecological integrity, and restoration success. We examined responses by oyster-reef-associated macrofauna to a hypoxic event across three subtidal oyster-reef complexes in western Mississippi Sound as part of a large-scale restoration program. Four hypotheses within the context of a Linear mixed model examined differences in the following: (1) the macrofauna relative to the hypoxic event; (2) subregions relative to the severity of hypoxia; (3) responses by key macrofaunal taxa; and (4) short-term macrofaunal recovery. Densities and production potential of the entire oyster-reef macrofaunal community as well as for six key taxa all abruptly decreased in connection with the hypoxic event. Overall, total production potential and total density were four-fold lower in the summer of 2015 during the hypoxic event than in the summer of 2014. The degree of macrofaunal impact corresponded with the severity of hypoxia on the landscape scale. Total density and total production averaged nearly three-fold lower and more than eight-fold lower respectively across two critically hypoxic reef complexes compared to the least affected reef complex. Taxon-specific responses depended on tolerances to hypoxia as well as modes of reproduction and dispersal. Short-term macrofaunal recovery indicated surprising ecological resilience relative to the hypoxic interruption. Detrimental macrofaunal effects ameliorated substantially within several months when total production potential was comparable to that of the previous year. However, the short-term recovery of key taxa varied with respect to the hypoxic event. Hypoxia-induced seasonal directionality reversed between summer 2015 and fall 2015, as evidenced by lower values for total density, total production, and the density and production of the larger-bodied crustaceans, Eurypanopeus and Palaemonetes. Secondary production offers a key functional indicator of multiple ecosystem services and an informative gauge of ecological disturbance. Associated macrofauna should be used more widely to assess the ecological function and recovery of oyster reefs. This study expands our understanding of a productive oyster reef ecosystem that is threatened by multiple environmental challenges. [ABSTRACT FROM AUTHOR]

There is a void in the knowledge of the acidification status of Eastern Canada's coastal waters. This knowledge is crucial to evaluating the threats posed to marine life, particularly oyster farming, a flagship of New Brunswick seafood production. In this study, we measured the temporal variability of pH and related environmental parameters in three bays of Northeastern New Brunswick. We also evaluated the potential impact of the observed pH levels on the Eastern oyster (Crassostrea virginica Gmelin, 1791), based on the available literature on this species' sensitivity to acidification. We investigated the presence of inherent cycles of pH with the Fourier transform and the spectral filtering technique. Our results show that pH is highly variable in the studied area, with values ranging from 7.31 to 8.90. A seasonal effect was apparent, as the pH fluctuations were set at the lowest level in winter when the cover of ice and snow on the bay was present. The spectral analysis revealed a clear semidiurnal tidal pattern of pH, this variable being inversely related to the water level in summer and directly related to it in winter. The spectral subtraction of all the tidal components allowed the detection of a circadian rhythm that was not in pace with the alternation between day and night but rather slowly drifted so that the pH troughs occurred at night during the full moon period. Short periodicities of circa 8 and 6 h also existed in two of the three bays. Based on current knowledge of C. virginica's sensitivity to acidification, this species' recruitment, growth, and survival are unlikely to be impacted by the present pH levels in the studied area. However, further acidification might overcome the resilience of C. virginica, especially that of the larvae that are produced during the winter in commercial hatcheries. [ABSTRACT FROM AUTHOR]

In the "Blue Bay Remediation Action" project, the oyster reef plays the dual role of ecological restoration and wave suppression, and the study of the effect of oyster reef wave dissipation forms the basis of relevant projects. Taking the Binzhou oyster reef ecological restoration project as its object, this paper studied the wave-dissipating effect of the oyster reef, using the SWAN model. The simulation results showed that after the deployment of oyster reefs in extreme high-water-level conditions, they could produce a wave-dissipation effect, with a wave-dissipation rate between 8% and 21%. Significant wave-dissipation effects can be produced under the designed high-water-level conditions, with a wave-height dissipation rate of 42% to 65%. Among them, the wave-dissipation effect of oyster reefs was more significant for waves coming from the ENE, NE, N, and NNE directions. This study could provide a scientific reference for the design and layout of oyster reefs. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Predator–prey interactions are a key feature of ecosystems and often chemically mediated, whereby individuals detect molecules in their environment that inform whether they should attack or defend. These molecules are largely unidentified, and their discovery is important for determining their ecological role in complex trophic systems. Homarine and trigonelline are two previously identified blue crab (Callinectes sapidus) urinary metabolites that cause mud crabs (Panopeus herbstii) to seek refuge, but it was unknown whether these molecules influence other species within this oyster reef system. In the current study, homarine, trigonelline, and blue crab urine were tested on juvenile oysters (Crassostrea virginica) to ascertain if the same molecules known to alter mud crab behavior also affect juvenile oyster morphology, thus mediating interactions between a generalist predator, a mesopredator, and a basal prey species. Oyster juveniles strengthened their shells in response to blue crab urine and when exposed to homarine and trigonelline in combination, especially at higher concentrations. This study builds upon previous work to pinpoint specific molecules from a generalist predator's urine that induce defensive responses in two marine prey from different taxa and trophic levels, supporting the hypothesis that common fear molecules exist in ecological systems. [ABSTRACT FROM AUTHOR]

Recently, our in vitro study on the effects of plasma-activated simulated seawater (PASW) demonstrated its potential as a novel, alternative disinfectant in oyster depuration. In this current study, PASW's physicochemical and antimicrobial properties were identified and its effects on oyster quality were observed. Simulated seawater (SS) activated by plasma for 10 min (PASW10) increased in temperature, oxidation reduction potential, and electrical conductivity with a decrease in those parameters after 1:1 dilution with SS (PASW10 (1:1)). The pH decreased immediately after plasma activation and subsequently increased after dilution. Nitrate and nitrite concentrations were higher in PASW10 (1:1) compared to PASW10 (3:1). No free available chlorine was detected in undiluted PASW10. Processing using SS and PASW10 (1:1) depuration and refrigeration of E. coli-bioaccumulated oysters was observed. Significantly higher reductions in total coliform and E. coli were noted for PASW10 (1:1) treated oyster samples after 24 h compared to refrigerated samples. No significant differences in values for condition index or biting force of oyster meats were observed for the processed samples after 24 h. Overall, the novel and environment-friendly PASW could be used as an alternative antimicrobial disinfectant in oyster depuration systems because it does not negatively affect an oyster's viability or quality. [ABSTRACT FROM AUTHOR]

The conversion of toxic Fe2+ into non-toxic Fe3+ stored in the inner cavity of ferritin nanocage could effectively reduce the occurrence of the Fenton reaction and inhibit the formation of harmful reactive oxygen species (ROS). In this study, we reveal that oyster ferritin (GF1) can rely on its high catalytic activity (7.7 times that of rHuHF) and high binding ability of Fe2+ (9.1 times that of rHuHF) to reduce the precursors of Fenton reaction, thus inhibiting the occurrence of Fenton reaction and slowing down reactive oxygen species-mediated inflammation. The above significant advantage of GF1 can be attributed to the Asp at the position 120th, which could increase the negatively charged area of three-fold channels from 37.8% (rHuHF) to 67.8% and then enhance its oxidation rate and ability of GF1. The findings are of great value in advancing novel nanoparticle drug design based on crystalline structure. [Display omitted] • Asp120 of oyster ferritin had a contribution to the catalytic oxidation rate of Fe2+. • Oyster ferritin shows the catalytic activity of 7.7 times higher than that of rHuHF. • Oyster ferritin shows the binding ability of 9.1 times higher than that of rHuHF. • Oyster ferritin could significantly reduce the precursors of Fenton reaction. [ABSTRACT FROM AUTHOR]

There is increasing awareness of boat sound effects on coral reef assemblages. While behavioral disturbances have been found in fishes, the effects on marine invertebrates remain largely unknown. Here, the behavioral effects of recreational boat sound on thorny oysters at two coral reef habitats within the U.S. Virgin Island National Park were assessed. The "treatment" site was characterized by frequent boat traffic, which increased daytime mean particle acceleration levels (PALrms) by more than 6 dB, while mean PALrms at the "control" site were not contaminated by boat sound. Despite these contrasting soundscapes, all oysters showed the same diurnal cycle, with their valves open at night and partially closed during the day. There was no statistical evidence of behavioral responses in oysters exposed to daytime boat sound. This can be explained by low auditory sensitivity, habituation to a noisy environment due to the pervasiveness of boat sound pollution, or that boat sound may not represent an immediate concern for this species. These findings contrast with laboratory studies that have shown behavioral responses in bivalves exposed to boat sound, highlighting the need for more realistic field-based studies when evaluating potential effects of anthropogenic sounds on this group. [ABSTRACT FROM AUTHOR]

The regeneration of bone defects is a major challenge for clinical orthopaedics. Herein, we designed and prepared a new type of bioactive material, using stingray skin collagen and oyster shell powder (OSP) as raw materials. A stingray skin collagen/oyster osteoinductive composite scaffold (Col-OSP) was prepared for the first time by genipin cross-linking, pore-forming and freeze-drying methods. These scaffolds were characterized by ATR-FTIR, SEM, compression, swelling, cell proliferation, cell adhesion, alkaline phosphatase activity, alizarin red staining and RT-PCR etc. The Col-OSP scaffold had an interconnected three-dimensional porous structure, and the mechanical properties of the Col-OSP composite scaffold were enhanced compared with Col, combining with the appropriate swelling rate and degradation rate, the scaffold was more in line with the requirements of bone tissue engineering scaffolds. The Col-OSP scaffold was non-toxic, promoted the proliferation, adhesion, and differentiation of MC3T3-E1 cells, and stimulated the osteogenesis-related genes expressions of osteocalcin (OCN), collagen type I (COL-I) and RUNX2 of MC3T3-E1 cells. [ABSTRACT FROM AUTHOR]

The mangrove oyster (Crassostrea gasar) is Brazil's second most cultured species and presents a high potential for aquaculture. However, artificial selection in a highly fecund species and significant variance in reproductive success can result in the loss of genetic diversity and increases the inbreeding rate, especially in cultivated populations. In this study, we investigated the genetic structure and diversity of C. gasar in wild and cultivated populations using 14 microsatellites. Spatial genetic comparisons revealed the existence of two main genetic groups of C. gasar, one comprising the population in cultivation and the other formed by wild populations along the southern and southeastern Brazilian coasts. Although no common genetic structure exists among wild populations, it is possible to observe a distribution gradient based on discriminant analysis of principal components consistent with their geographic distribution. However, it is insufficient to differentiate them genetically. Despite artificial reproduction, the genetic diversity values of the cultivated population remained relatively high and did not show a reduction. Therefore, monitoring the cultivated population and establishing reference values for genetic diversity will allow the adoption of strategies both for the viability of the cultivated population and the management of wild populations. [ABSTRACT FROM AUTHOR]

Intertidal reefs of Crassostrea virginica (eastern oyster) provide ecologically valuable habitat in estuaries along the Atlantic coast of North America. In Mosquito Lagoon, a shallow-water estuary on the east coast of central Florida, USA, historical aerial imagery was used to document a 24% decline in the live C. virginica reef area between 1943 and 2009. Using 2021 imagery, every living and dead reef in the same region was manually digitized to identify changes during the intervening 12 years. Positive impacts of C. virginica reef restoration that took place between 2007 and 2021 were also digitized to quantify long-term restoration impact. Natural, live C. virginica reef coverage throughout the system was found to have decreased by 50.6% between 2009 and 2021 and, thus, 62.6% between 1943 and 2021. This was attributed to reef fragmentation, reef footprint loss, boating activity, and mangrove expansion. Of the 2542 live reefs identified using 2009 imagery, 219 reefs fragmented, 988 reefs no longer had an identifiable footprint, and 598 reefs contained visible mangroves with non-continuous canopies. Conservatively, 63.6% of directly restored reef area was classified as living reef in 2021, and 74.5% of restoration projects were more than 50% live reef. Dead reef area decreased by 57.9% throughout the system. Understanding changes in C. virginica reef acreage, reef numbers, and mangrove expansion is essential for resource management, restoration practices, and tracking climate change impacts on publicly protected estuaries. [ABSTRACT FROM AUTHOR]

Physical structures generated from ecosystem engineers can have a cascade of impacts on the ecological community and the surrounding landscape. The Eastern oyster Crassostrea virginica can form extensive intertidal reefs, whose three‐dimensional structures provide ecosystem services like nursery and foraging habitat for fishes and invertebrates and shoreline stabilization. Measurements of the structural properties of these reefs provide opportunities to quantitatively assess associated services. There is a growing variety of tools available for measuring three‐dimensional (3D) properties of intertidal habitats, including two remote sensing methods that capture 3D structural metrics in a number of environments. We surveyed reefs using a terrestrial laser scanner (TLS, LiDAR) and imagery from unoccupied aircraft systems (UAS, or drones) processed through Structure from Motion photogrammetry. Comparisons of digital elevation models from repetitive flights over an oyster reef to checkpoints yielded mean horizontal and vertical root mean square errors (RMSE) of −0.54 ± 0.47 cm and 0.97 ± 1.0 cm (Mean ± SD), respectively, indicating high accuracy among UAS surveys. Compared to TLS products, point cloud densities from UAS‐derived products were more consistent across the reef elevation gradient and much denser overall except in the low reef zone, which was proximal to most of the TLS scan locations. Comparisons of structural metrics between UAS and TLS showed similarities in metrics like profile and planform curvatures, yet indicated UAS surveys produced higher values of surface complexity and slope. Results indicate that UAS photogrammetry can produce robust oyster reef structural metrics that can be highly useful in oyster conservation and restoration. [ABSTRACT FROM AUTHOR]

Abstract Comparing the responses of closely related species to environmental changes is an efficient method to explore adaptive divergence, for a better understanding of the adaptive evolution of marine species under rapidly changing climates. Oysters are keystone species thrive in intertidal and estuarine areas where frequent environmental disturbance occurs including fluctuant salinity. The evolutionary divergence of two sister species of sympatric estuarine oysters, Crassostrea hongkongensis and Crassostrea ariakensis, in response to euryhaline habitats on phenotypes and gene expression, and the relative contribution of species effect, environment effect, and their interaction to the divergence were explored. After a 2‐month outplanting at high‐ and low‐salinity locations in the same estuary, the high growth rate, percent survival, and high tolerance indicated by physiological parameters suggested that the fitness of C. ariakensis was higher under high‐salinity conditions and that of C. hongkongensis was higher under low‐salinity conditions. Moreover, a transcriptomic analysis showed the two species exhibited differentiated transcriptional expression in high‐ and low‐salinity habitats, largely caused by the species effect. Several of the important pathways enriched in divergent genes between species were also salinity‐responsive pathways. Specifically, the pyruvate and taurine metabolism pathway and several solute carriers may contribute to the hyperosmotic adaptation of C. ariakensis, and some solute carriers may contribute to the hypoosmotic adaptation of C. hongkongensis. Our findings provide insights into the phenotypic and molecular mechanisms underlying salinity adaptation in marine mollusks, which will facilitate the assessment of the adaptive capacity of marine species in the context of climate change and will also provide practical information for marine resource conservation and aquaculture.

Food and waterborne protozoan pathogens can cause serious disease in people. Three common species Cryptosporidium parvum, Giardia enterica and Toxoplasma gondii can contaminate diverse shellfish species, including commercial oysters. Current methods of protozoan detection in shellfish are not standardized, and few are able to simultaneously identify multiple species. Here, we present a novel metabarcoding assay targeting the 18S rRNA gene followed by next generation sequencing (NGS) for simultaneous detection of Cryptosporidium spp., Giardia spp. and T. gondii spiked into oyster samples. We further developed a bioinformatic pipeline to process and analyze 18S rRNA data for protozoa classification. The ability of the NGS assay to detect protozoa was later compared with conventional PCR. Results demonstrated that background amplification of oyster and other eukaryotic DNA competed with that of protozoa for obtained sequence reads. Sequences of target protozoans were obtained across all spiking levels; however, low numbers of target sequences in negative controls imply that a threshold for true positives must be defined for assay interpretation. While this study focused on three target parasites, the ability of this approach to detect numerous known and potentially unknown protozoan pathogens make it a promising screening tool for monitoring protozoan contamination in food and water.

Humans have consumed bivalve molluscs, such as mussels, scallops and oysters, and used their shells since prehistoric times. However, there are still discoveries to be made and lessons to be learnt in areas including their unusual adhesion, optics and longevity. Michael Gross reports. Humans have consumed bivalve molluscs, such as mussels, scallops and oysters, and used their shells since prehistoric times. However, there are still discoveries to be made and lessons to be learnt in areas including their unusual adhesion, optics and longevity. [ABSTRACT FROM AUTHOR]

This article discusses the importance of including First Nations peoples in coastal and oyster reef restoration projects. It highlights the need to go beyond ecological considerations and prioritize cultural revitalization outcomes for Indigenous communities. The article emphasizes the advantages of meaningful engagement with First Nations peoples throughout the restoration process, including the embedding of cultural values and metrics of success, increased understanding of threats to oyster reefs, and the opportunity for cultural revitalization and retention. The article also calls for co-management and co-governance programs that privilege Indigenous knowledge and leadership. [Extracted from the article]

Norovirus (NOV) and hepatitis A virus (HAV) are human enteric viruses of major concern worldwide. Salad vegetables and molluscan shellfish are highly susceptible to contamination by NOV and HAV and can pose a health threat when consumed raw. The objective of this study was to determine the occurrence of NOV and HAV in lettuce, watercress, tomatoes, and oysters using the enzyme-linked immunosorbent assay and assess the health risks associated with consumption of these commodities by semi-quantitative risk assessment. The occurrence of NOV in vegetables ranked in the following decreasing order: lettuce (36%) > watercress (16%) > tomatoes (4%). However, HAV was more frequently detected in watercress (56%), compared to lettuce or tomatoes (12%). Additionally, NOV was detected in oysters (60%). The risk assessment exercise pointed to a medium-risk score of contracting a foodborne illness of viral origin for consumers eating fresh watercress or oysters. Future research will ascertain the presence of these enteric viruses in a broader range of food commodities.

The aim of the present study was to evaluate Vibrio parahaemolyticus occurrences in bivalve molluscs harvested from Sardinian coastal environments between 2013 and 2015. The prevalence of pathogenic V. parahaemolyticus isolates is based on the detection of the two major virulence genes thermostable direct hemolysin (tdh) and thermolabile hemolysin (trh) To assess changes between 2011 and 2018 in the prevalence of V. parahaemolyticus in bivalve molluscs, we compared our results with those of previous investigations. In total, 2,933 samples were collected: 1,079 in 2013, 1,288 in 2014, and 566 in 2015. The mean prevalence of V. parahaemolyticus in shellfish was 3.5% in 2013, 1.7% in 2014, and 3.5% in 2015. The highest percentage of positive samples in 2013 and 2014 was observed in clams (3.5% and 2.7%, respectively), whereas in 2015, it was reported in oysters (15.1%). By comparing the sampling period of 2011–2014 with that of 2015–2018, an increase in the prevalence of V. parahaemolyticus was observed in shellfish (p

The enteric parasite Cryptosporidium is spread through the fecal-oral pathway, most commonly by the consumption of contaminated water but also through food. Because eating raw or barely cooked shellfish might put consumers at risk for cryptosporidiosis, identifying the parasite in oysters is important for public health. A total of 240 oysters, collected from two shellfish aquaculture sites in Thailand's Gulf coast, Nakhon Si Thammarat and Surat Thani, were tested for the presence of Cryptosporidium. Escherichia coli, enterococci, and thermotolerant coliform total levels were measured to assess seawater quality in the shellfish production regions. Oocysts of Cryptosporidium spp. were detected in 13.8% of the samples processed by immunofluorescence analyses. The detection of Cryptosporidium spp. oocysts in oysters obtained from Surat Thani (17.5%) was higher than in those obtained from Nakhon Si Thammarat (9.2%). The difference in detection of positive samples obtained from Nakhon Si Thammarat and those obtained from Surat Thani may be attributed to the effects of physical, ecological, and anthropogenic conditions, resulting in an increased level of marine water contamination by Cryptosporidium spp. oocysts. These findings demonstrate that native commercial oysters obtained from Thailand's southern Gulf coast contained Cryptosporidium spp. oocysts which might serve as a source of human infection. Consequently, these findings pose a serious public health concern and suggest that more quality control measures need to be implemented by the oyster aquaculture business to ensure the safety of seafood.

High-temperature stress caused by global climate change poses a significant threat to marine ectotherms. This study investigated the role of protein phosphorylation modifications in the molecular regulation network under heat stress in oysters, which are representative intertidal organisms that experience considerable temperature changes. Firstly, the study compared the extent of thermal damage between two congeneric oyster species, the relative heat-tolerant Crassostrea angulata (C. angulata) and heat-sensitive Crassostrea gigas (C. gigas), under sublethal temperature (37 °C) for 12 h, using various physiological and biochemical methods. Subsequently, the comparative proteomic and phosphoproteomic analyses revealed that high-temperature considerably regulated signal transduction, energy metabolism, protein synthesis, cell survival and apoptosis, and cytoskeleton remodeling through phosphorylation modifications of related receptors and kinases. Furthermore, the protein kinase A, mitogen-activated protein kinase 1, tyrosine-protein kinase Src, and serine/threonine kinase AKT, exhibiting differential phosphorylation modification patterns, were identified as hub regulators that may enhance glycolysis and TCA cycle to increase the energy supply, distribute protein synthesis, inhibit Caspase-dependent apoptosis activated by endogenous mitochondrial cytochrome release and maintain cytoskeletal stability, ultimately shaping the higher thermal resistance of C. angulata. This study represents the first investigation of protein phosphorylation dynamics in marine invertebrates under heat stress, reveals the molecular mechanisms underlying the differential thermal responses between two Crassostrea oysters at the phosphorylation level, and provides new insights into understanding phosphorylation-mediated molecular responses in marine organisms during environmental changes and predicting the adaptive potential in the context of global warming.

Metagenomics analysis of foods has the potential to provide comprehensive data on the presence and prevalence of antimicrobial resistance (AMR) genes in the microbiome of foods. However, AMR genes are generally present in low abundance compared to other bacterial genes in the food microbiome and consequently require multiple rounds of in-depth sequencing for detection. Here, a metagenomics approach, using bait-capture probes targeting antimicrobial resistance and plasmid genes, is used to characterize the resistome and plasmidome of retail beef, chicken, oyster, shrimp, and veal enrichment cultures (n  =  15). Compared to total shotgun metagenomics, bait-capture required approximately 40-fold fewer sequence reads to detect twice the number of AMR gene classes, AMR gene families, and plasmid genes across all sample types. For the detection of critically important extended spectrum beta-lactamase (ESBL) genes the bait capture method had a higher overall positivity rate (44%) compared to shotgun metagenomics (26%), and a culture-based method (29%). Overall, the results support the use of bait-capture for the identification of low abundance genes such as AMR genes from food samples. [ABSTRACT FROM AUTHOR]

Chama coralloides Reeve, 1846 is a commercially important mollusk in Acapulco, Mexico. There is currently no fisheries regulation or protection. Therefore, the objective of the present work was to estimate the growth parameters of C. coralloides using the Schnute model cases. Shell length data collected from March 2019 to December 2021 were used. A multinomial analysis was performed to determine the modal groups monthly. Using the mean lengths of each modal group, a modal progression was performed to define the time increments ∆t, which were taken as equivalent representations of the data from direct age estimation methods (mark-recapture). These data were used to estimate the individual growth parameters using the five cases of the Schnute model and to define the case that best describes the growth. 2804 organisms were analyzed, with lengths ranging from 7.61 to 116.30 mm SL. Multinomial analysis showed one to four modal groups per month and 14 cohorts were identified. The best-fit case was case 5 (wi = 0.72) with an L∞ = 114.2 mm, followed by case 1 (wi = 0.28) with an L∞= 109.8 mm. Both cases (5 and 1) were modeled and because the best model did not reach 90%, a mean model was estimated. C. coralloides presented a type of asymptotic growth, with an estimated L∞ that can be reached nearly 22 years. [ABSTRACT FROM AUTHOR]

In this study, the antioxidant effects of gallic acid (GA) and its alkyl esters including methyl gallate (MG), butyl gallate (BG), octyl gallate (OG), and lauryl gallate (LG) in whole oyster meats and oyster meat homogenates during cold storage are investigated. The oxidation degree of lipid is measured by peroxide value (POV), thiobarbituric acid active substances (TBARS), and polyunsaturated fatty acid (PUFA) percentage. The results show that the lipid oxidation in the two types of samples is inhibited by GA alkyl esters, and the antioxidant effects first increase and then decrease along with the extension of the chain length, among the esters, BG and OG are relatively more effective. Therefore, it is speculated that the antioxidant capacity of GA alkyl esters may be influenced by hydrophobicity and follows a "cut‐off effect" in whole oyster meats and oyster meat homogenates. Practical application: Seafood is easily oxidized even under cold storage because it contains more PUFA. Antioxidants are widely used to inhibit lipid oxidation. In this study, the antioxidant capacity of GA alkyl esters in whole oyster meats and oyster meat homogenates is investigated, which improves the selection of suitable antioxidants to strengthen the oxidation stability of oyster samples for cold storage. [ABSTRACT FROM AUTHOR]

Oysters play an important role in coastal ecology and are a globally popular seafood source. However, their filter-feeding lifestyle enables coastal pathogens, toxins, and pollutants to accumulate in their tissues, potentially endangering human health. While pathogen concentrations in coastal waters are often linked to environmental conditions and runoff events, these do not always correlate with pathogen concentrations in oysters. Additional factors related to the microbial ecology of pathogenic bacteria and their relationship with oyster hosts likely play a role in accumulation but are poorly understood. In this study, we investigated whether microbial communities in water and oysters were linked to accumulation of Vibrio parahaemolyticus, Vibrio vulnificus, or fecal indicator bacteria. Site-specific environmental conditions significantly influenced microbial communities and potential pathogen concentrations in water. Oyster microbial communities, however, exhibited less variability in microbial community diversity and accumulation of target bacteria overall and were less impacted by environmental differences between sites. Instead, changes in specific microbial taxa in oyster and water samples, particularly in oyster digestive glands, were linked to elevated levels of potential pathogens. For example, increased levels of V. parahaemolyticus were associated with higher relative abundances of cyanobacteria, which could represent an environmental vector for Vibrio spp. transport, and with decreased relative abundance of Mycoplasma and other key members of the oyster digestive gland microbiota. These findings suggest that host and microbial factors, in addition to environmental variables, may influence pathogen accumulation in oysters. [ABSTRACT FROM AUTHOR]

Restoration aims to reverse the global declines of foundation species, but it is unclear how project attributes, the physical setting, and antecedent conditions affect restoration success. In coastal seas worldwide, oyster reef restoration is increasing to counter historical habitat destruction and associated declines in fisheries production and biodiversity. Yet, restoration outcomes are highly variable and the factors that enhance oyster production and nekton abundance and diversity on restored reefs are unresolved. To quantify the drivers of oyster restoration success, we used meta‐analysis to synthesize data from 158 restored reefs paired with unstructured habitats along the United States Gulf and Atlantic coasts. The average recovery of oyster production was 65% greater in subtidal (vs. intertidal) zones, 173% greater in polyhaline (vs. mesohaline) environments and increased with tidal range, demonstrating that physical conditions can strongly influence the restoration success of foundation species. Additionally, restoration increased the relative abundance and richness of nektonic fishes and invertebrates over time as reefs aged (at least 8 years post‐construction). Thus, the restoration benefits for provisioning habitat and enhancing biodiversity accrue over time, highlighting that restoration projects need multiple years to maximize ecosystem functions. Furthermore, long‐term monitoring of restored and control sites is needed to assess restoration outcomes and associated drivers. Last, our work reveals data constraints for several potential drivers of restoration outcomes, including reef construction material, reef dimensions, harvest pressure and disease prevalence. More experimental and observational studies are needed to target these factors and measure them with consistent methods across studies. Our findings indicate that the assisted recovery of foundation species yields several enhancements to ecosystem services, but such benefits are mediated by time and environmental conditions. [ABSTRACT FROM AUTHOR]

Eastern oysters, Crassostrea virginica, are ecologically and economically important coastal species which provide a commercially valuable food product while also improving water quality through filtration, protecting shorelines, and providing habitat. The protozoan parasites Perkinsus marinus and Haplosporidium nesloni commonly infect oysters along the United States Atlantic and Gulf coasts and have been linked to poor oyster health and mass mortality events. In this study, wild oysters were collected from multiple reefs within four tidal creeks along the coast of Georgia to investigate P. marinus and H. nelsoni prevalence and intensity, their potential impact on oyster health, and identify possible drivers of the parasites. A second study occurred on four sites on Sapelo Island, Georgia, with continuous water quality monitoring data to further elucidate potential drivers. Oyster density and condition index, a proxy for health, were measured, and parasites were quantified using a TaqMan probe based quantitative real-time PCR within gill tissue. Real-time PCR showed that 86% of oysters tested were infected by one or both parasites in the coast-wide survey, and 93% of oysters from Sapelo Island were also infected by one or both parasites. Prevalence and infection intensity for both P. marinus and H. nelsoni varied across sites. Overall impacts on oysters were complex—intensity was not linked to oyster metrics in the coastwide study, but oyster condition was negatively correlated with P. marinus prevalence in the Sapelo Island study. Several relationships between both parasites and water quality parameters were identified, providing valuable information about potential drivers that should be investigated further. [ABSTRACT FROM AUTHOR]

Copyright of Spal: Revista de Prehistoria y Arqueologia de la Universidad de Sevilla is the property of Spal. Revista de Prehistoria y Arqueologia de la Universidad de Sevilla and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The prevalence and intensity of dermo Perkinsus marinus were examined in the eastern oyster Crassostrea virginica "southern oyster" population within the high salinity (35‰ or greater) waters of South Texas' lower Laguna Madre (LLM). During 2017, 192 oysters from four collection sites (approximately 111 km2 study area) were examined via culture for the presence of Perkinsus hypnospores. Additionally, dermo DNA was detected in oysters by PCR. The number of oysters infected (prevalence = 0.36), as well as the intensity of infection, were consistent within three of the four collection sites but varied between sites, suggesting that environmental differences influence P. marinus infection in the LLM. All sites showed an upward trend in the number of oysters infected as oyster size increased, yet the highest infection intensities were not found predominately in the larger oysters. Although the warm, high‐salinity waters might be expected to be ideal for dermo infection, the relative number and intensity of infections were low for most sites, suggesting that dermo in the LLM may not pose a significant threat to commercial oyster culture and that the southern oyster may be uniquely suited for developing a strain of oysters suitable for offshore culture in the Gulf of Mexico. [ABSTRACT FROM AUTHOR]

Sponges, especially Calcarea, are minor components of benthic associations, especially during the Mesozoic. In the Lower Cretaceous of the Neuquén Basin, small calcareous sponges have been found building a small monospecific meadow. It is restricted to a marlstone lens-shaped bed in a quiet outer-ramp setting in the Cerro Marucho Locality (Picún Leufú depocentre), above a shell bed of small exogyrid oysters; oysters and sponges were the only preserved macrobenthic faunal elements. Individual sponges were small, under 4 cm high, and presented a sub-cylindrical morphology with one or more rounded, apical osculi, many inhalant openings and triactine spicules. Specimens studied here were assigned to Endostoma sp. aff. Endostoma nodosa. These sponges are quite commonly encrusted by exogyrid oysters, serpulids, sabellids, agglutinating foraminifers and cyclostome bryozoans. Overgrowths among sclerobionts were common, though no undoubtedly in vivo interaction has been recorded. Disarticulated left oyster valves were frequently bioclaustrated by the sponges, showing that in vivo settlement upon sponges was common. Many oysters settled in the periphery of the osculum suggesting a commensal relationship. The study of this sponge meadow and its sclerobiont community allowed the identification of different stages of ecological succession. The pioneer stage was characterised by sponge settlement on oyster valves, within an otherwise soft consistency bottom. High sedimentation or high nutrient inputs, either individually or in combination, could explain the great abundance of oysters. During the climax stage, sponges thrived and harboured several sclerobiont taxa, developing a relatively dynamic palaeocommunity. Finally, an intensification in either sedimentation rates or nutrient input (or both) past the tolerable threshold for sponges may have been the cause(s) of the meadow's demise. Endostoma and similar forms were up to now reported mostly from the Jurassic and Cretaceous of Europe as accessory builders, or as accompanying fauna in reefal settings. This new record shows that in rare occasions they could form low-relief meadows on their own. [ABSTRACT FROM AUTHOR]

It has long been suggested by commercial fishing interests that the sea bed benefits from being trawled or disturbed. Evidence to support increased benthic food web productivity in areas disturbed by trawling has suggested that this is the case, and that some mobile consumers can benefit from this increased productivity.The same hypothesis has been put forward for shellfish recruitment, that disturbance of the sea bed, e.g. 'harrowing', increases the exposure of suitable settlement substrates for shellfish larvae. This is an approach often taken in shellfish mariculture in private fisheries, and has led to calls for support of expanding such activities into publicly managed areas to promote shellfish recovery and restoration.Increased seabed disturbance, however, may not align with conservation policy or societal objectives for natural recovery of the seabed landscape. Furthermore, evidence for increased shellfish recruitment from seabed disturbance is mixed, and many attempts to elucidate whether relationships exist receive criticism for operating at small spatial and temporal scales.An analysis is presented from 3 years of data (2016–2018) from a stock survey of a private European flat oyster, Ostrea edulis, fishery operating in the Blackwater estuary, Essex, UK. Using data for adult and recruit oyster abundance and distribution in 2018, with 'harrowing' effort from 2016–2018, it is asked whether oyster recruitment was related to disturbance effort.It was found that oyster recruitment is positively related to increased seabed disturbance, but only up to intermediate adult oyster abundance equivalent to 60 oysters/100 m dredge, beyond which harrowing results in recruitment declines. This has implications for approaches to oyster fishery recovery, but also for restoration projects seeking evidence‐led guidance on which ways may be appropriate to kick‐start natural recovery in historical oyster areas that are habitat limited. [ABSTRACT FROM AUTHOR]

The development of tourism and intensification of agriculture has released large amounts of nitrogen and phosphorus into the Mar Menor coastal lagoon in South‐east Spain, resulting in a phytoplankton bloom in 2016. This bloom turned the clear and transparent waters turbid and greenish, and killed approximately 85% of benthic macrophytes.Nutrient bioextraction by flat oysters, Ostrea edulis, has been proposed for remediation of these eutrophication events and water quality recovery.This research aims to quantify the clearance rate and investigate the genetic origin of Mar Menor oysters under eutrophized conditions for potential applications to bioremediation projects. Oligotrophic and eutrophic conditions were replicated in the laboratory, and oyster feeding behaviour (i.e. clearance rates, ingestion rates, absorption efficiency and absorption rates) were studied using a flow‐through system.The genetic characterization of oysters showed no significant difference between individuals from the Mar Menor and individuals collected from a nearby Mediterranean bed (Tabarca Island).Based on the physiological results observed, oysters were grouped into high‐feeder (HF) and low‐feeder (LF) categories according to their clearance rate, that was 3‐fold higher in the HF group. Different responses in feeding behaviour were observed under eutrophic conditions in both oyster groups. Constraints in the absorption capacity of LF oysters seemed to be related to their reduced filtering activity. Lower body condition of LF oysters was evidenced by their negative scope for growth value.From this work, several conclusions can be drawn for future restoration/bioextraction actions: (i) the recovery of half of the oyster population that existed in the past would act as an effective top‐down control on the phytoplankton community; (ii) using clearance rate measurements is recommended to select oysters as broodstock; and (iii) Mediterranean oysters could be used as broodstock in the event that Mar Menor oysters fail to reproduce. [ABSTRACT FROM AUTHOR]

Ecological restoration includes specific technical phases over the course of an ecosystem recovery process. In the marine environment and for oyster reef restoration, the installation and implementation of pilot reefs close the gap between feasibility studies with small‐scale experiments and designated upscaling for marine conservation measures.Against this background, this study presents the design, planning and installation of the first pilot oyster reef in offshore sublittoral regions of the North Sea. The work was conducted as part of marine protected area management in the Natura 2000 site Borkum Reef Ground in the German Bight, in the area of historical offshore oyster grounds.It includes logistical considerations, material selection, methodology for reef base construction and deployment of European flat oysters Ostrea edulis as spat‐on‐shell, young and adult single seed oysters, and spat‐on‐reef, as well as the development of an efficient monitoring approach for reef‐associated biodiversity.Native Oyster Restoration Alliance monitoring methodologies, such as underwater visual census and seabed images were selected, tested and successfully adapted for the pilot oyster reef and study site. The evaluation and optimization of offshore sublittoral oyster reef monitoring are presented here, and biodiversity metrics are put into perspective with data from recent and historical studies.Results show a few mobile fauna species (e.g., fish and decapods) as first colonizers after reef construction. One year later, biodiversity increased due to a larger number of invertebrate and fish species. However, the pilot oyster reef community still represents an early recolonization stage, with lower biodiversity than historical records.This study presents a proof of concept for the design, planning and construction of an offshore oyster reef and indicates stages in the recovery process. Strategies to optimize and to complement reef‐monitoring in challenging environments are discussed, emphasizing additional molecular and functional analyses for future assessments. [ABSTRACT FROM AUTHOR]

After centuries of overexploitation, European flat oyster (Ostrea edulis) habitats are increasingly being protected and large‐scale oyster habitat restoration projects have been initiated in the North Sea, the English Channel, the Irish Sea and the north‐eastern Atlantic.Understanding the habitat requirements of flat oysters is key in the selection process of restoration sites.In this study, a theoretical niche for all life stages of the flat oyster is determined using a dynamic energy budget model forced with temperature, chlorophyll a and salinity in combination with sediment composition. The suitability of Northern Europe's marine environment for flat oysters is evaluated by applying the proposed niche model on a spatial scale and evaluating spatio‐temporal variability in life history traits and metabolic characteristics, such as fitness, reproductive output, settlement success and growth.Results show that habitat suitability is limited by low maximum summer temperature and low food availability at higher latitudes and in areas under strong influence of the Atlantic Ocean. Restoration efforts in Ireland and Scotland should be confined to protected and shallow coastal environments. Suitability in the southern North Sea is patchy and mainly depends on seabed substrate. The nearshore areas of the English Channel are highly suitable.The georeferenced dataset shared in this study will be useful for restoration practitioners. [ABSTRACT FROM AUTHOR]