Articles de revues : « Crassostrea (Magallana) gigas »

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Chen, Citing, Wan Li, Jialong Gao, Wenhong Cao, Xiaoming Qin, Huina Zheng, Haisheng Lin et Zhongqin Chen. « Purification, Characterization, cDNA Cloning, and Bioinformatic Analysis of Zinc-Binding Protein from Magallana hongkongensis ». Molecules 29, n^o 4 (18 février 2024) : 900. http://dx.doi.org/10.3390/molecules29040900.

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Oysters contain significant amounts of the zinc element, which may also be found in their proteins. In this study, a novel zinc-binding protein was purified from the mantle of the oyster Magallana hongkongensis using two kinds of gel filtration chromatograms. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) showed that its molecular weight was approximately 36 kDa. The protein identified by the Q-Exactive mass spectrometer shared the highest sequence identity with carbonic anhydrase derived from Crassostrea gigas concerning amino acid sequence similarity. Based on homologous cloning and RACE PCR, the full-length cDNA of carbonic anhydrase from Magallana hongkongensis (designated as MhCA) was cloned and sequenced. The cDNA of MhCA encodes a 315-amino-acid protein with 89.74% homology to carbonic anhydrase derived from Crassostrea gigas. Molecular docking revealed that the two zinc ions primarily form coordination bonds with histidine residues in the MhCA protein. These results strongly suggest that MhCA is a novel zinc-binding protein in Magallana hongkongensis.

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Wolfe, Marah L., Chelsea M. Bowers-Doerning, Anabell Espinosa, Ty Frantz, William J. Hoese, Joann G. Lam, Kailee R. Lamp et al. « Intra-decadal increase in globally-spread Magallana gigas in southern California estuaries ». PLOS ONE 19, n^o 5 (8 mai 2024) : e0302935. http://dx.doi.org/10.1371/journal.pone.0302935.

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Introduction and establishment of non-indigenous species (NIS) has been accelerated on a global scale by climate change. NIS Magallana gigas’ (formerly Crassostrea gigas’) global spread over the past several decades has been linked to warming waters, specifically during summer months, raising the specter of more spread due to predicted warming. We tracked changes in density and size distribution of M. gigas in two southern California, USA bays over the decade spanning 2010–2020 using randomly placed quadrats across multiple intertidal habitats (e.g., cobble, seawalls, riprap) and documented density increases by 2.2 to 32.8 times at 7 of the 8 sites surveyed across the two bays. These increases in density were coincident with 2–4° C increases in median monthly seawater temperature during summer months, consistent with global spread of M. gigas elsewhere. Size frequency distribution data, with all size classes represented across sites, suggest now-regular recruitment of M. gigas. Our data provide a baseline against which to compare future changes in density and abundance of a globally-spread NIS of significant concern.

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Zhu, Ting, Chang Liu, Zhaoqun Liu, Yuqian Gao, Xiaoyu Xin, Lingling Wang et Linsheng Song. « A Cartilage Matrix Protein Regulates Collagen Synthesis in Mantle of Magallana gigas (Crassostrea gigas) under Ocean Acidification ». Fishes 8, n^o 6 (28 mai 2023) : 290. http://dx.doi.org/10.3390/fishes8060290.

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The shell biosynthesis of oysters plays a critical role in protection against environmental stress, in which cartilage matrix proteins (CMPs) determine the mineralogical and crystallographic properties of the shell. In the present study, a cartilage matrix protein (designated as MgCMP1) was identified from the Pacific oyster Magallana gigas (Crassostrea gigas) with the objective of understanding its possible role in shell formation. The open reading frame (ORF) of MgCMP1 was 1815 bp, encoding a polypeptide of 605 amino acids with two von Willebrand factor (VWA) domains. The mRNA transcript of MgCMP1 was expressed constitutively in all examined tissues with a higher level in the mantle, especially highest in the middle fold (MF) of the three folds of the mantle. In addition, the interaction between recombinant protein MgCMP1 (rMgCMP1) and recombinant protein bone morphogenesis protein 7 (rMgBMP7) was identified in vitro. After injection of dsRNA to inhibit the expression of MgCMP1, the mRNA expression level of Mgcollagen I and Mgcollagen X in the MF of the mantle significantly decreased. After pre-puncturing and acidification treatment (pH 7.8), the thickness and length of the new formation shells were lower than those in control group (pH 8.1), and the positive hybridization signals of the MgCMP1 mRNA transcript in the three mantle folds were obviously weakened, especially in the MF, whereas the mRNA expression level of MgCMP1, Mgcollagen I and Mgcollagen X in the MF of mantle decreased significantly. These results suggested that MgCMP1 was involved in regulating the expression of Mgcollagen I and Mgcollagen X in the MF of the mantle in response to ocean acidification (OA).

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De Rinaldis, Gianluca, Paolo Pastorino, Tommaso Scirocco, Claudia Sacchetti, Serena Anselmi, Francesca Provenza, Monia Renzi et Antonietta Specchiulli. « Navigating a Microplastic Sea : How the Pacific Cupped Oyster (Magallana gigas) Respond to Microplastic Pollution in Lagoons ». Toxics 12, n^o 6 (13 juin 2024) : 429. http://dx.doi.org/10.3390/toxics12060429.

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Microplastic pollution poses an escalating concern, particularly in coastal lagoons rich in biodiversity. This study delved into the occurrence of microplastics (MPs) in Magallana gigas (formerly Crassostrea gigas) from the Orbetello and Varano coastal lagoons (Italy), also investigating the response of these filter-feeding organisms to various colors (P = pink; B = blue; W = white) of high-density polyethylene (HDPE) MP fragments. Oysters were exposed for 7 days under controlled conditions. Subsequently, the oysters underwent analysis for both MP presence and biochemical markers of oxidative stress. Diverse ingestion rates of HDPE were noted among oysters from the two lagoons, eliciting antioxidant responses and modifying baseline activity. The two-way ANOVA revealed the significant effects of treatment (control; HDPE_B; HDPE_P; HDPE_W), site, and the interaction between treatment and site on all biomarkers. Non-metric multidimensional scaling showed a divergent effect of HDPE color on biomarkers. Further investigation is warranted to elucidate the mechanisms underlying the influence of MP color, dose-dependent effects, and the long-term impacts of exposure. Comprehending these intricacies is imperative for devising effective strategies to mitigate plastic pollution and safeguard marine health.

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Tran, Biet Thanh, Keun-Yong Kim, Jung Soo Heo, Su-Jin Park, Hong Keun Park et Youn Hee Choi. « Determination of the Pacific oyster Magallana gigas (Crassostrea gigas) diet composition in two aquaculture farms by fecal DNA metabarcoding ». Aquaculture 552 (avril 2022) : 738042. http://dx.doi.org/10.1016/j.aquaculture.2022.738042.

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Joyce, Patrick W. S., David M. Smyth, Jaimie T. A. Dick et Louise T. Kregting. « Coexistence of the native mussel, Mytilus edulis, and the invasive Pacific oyster, Crassostrea (Magallana) gigas, does not affect their growth or mortality, but reduces condition of both species ». Hydrobiologia 848, n^o 8 (7 mars 2021) : 1859–71. http://dx.doi.org/10.1007/s10750-021-04558-1.

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AbstractEcological impacts caused by invasive alien species can be severe but may vary depending upon environmental conditions. Many European populations of the native mussel, Mytilus edulis, have been invaded by the Pacific oyster, Crassostrea (Magallana) gigas. Although widespread invasions have occurred, interactions between M. edulis and C. gigas have largely been investigated with regards to competition for space and food as well as effects on species assemblages. Experimental investigation of competitive interactions on physiological responses of the two species requires further exploration. To this end, we used a 12-month field manipulation experiment to examine growth rates, mortality and condition indices of the two species occurring in monospecific and heterospecific groups. Growth rates and mortality of both species were similar in monospecific and heterospecific groups, whereas condition indices were significantly reduced for both species in heterospecific groups. Growth rates and condition indices also differed amongst experimental sites, potentially due to differing water motion. Shell weight-length relationships did not explain the observed differences in condition for either species. We show that coexistence between the two species may occur but could be detrimental for both species. We also provide a preliminary viewpoint that water motion can mediate competitive interactions between these species.

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Dhanji-Rapkova, Monika, Robert G. Hatfield, David I. Walker, Chantelle Hooper, Sarah Alewijnse, Craig Baker-Austin, Andrew D. Turner et Jennifer M. Ritchie. « Investigating Non-Native Ribbon Worm Cephalothrix simula as a Potential Source of Tetrodotoxin in British Bivalve Shellfish ». Marine Drugs 22, n^o 10 (5 octobre 2024) : 458. http://dx.doi.org/10.3390/md22100458.

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Tetrodotoxin (TTX) is a potent marine neurotoxin found in several phylogenetically diverse organisms, some of which are sought as seafood. Since 2015, TTX has been reported in bivalve shellfish from several estuarine locations along the Mediterranean and European Atlantic coasts, posing an emerging food safety concern. Although reports on spatial and temporal distribution have increased in recent years, processes leading to TTX accumulation in European bivalves are yet to be described. Here, we explored the hypothesis that the ribbon worm species Cephalothrix simula, known to contain high levels of TTX, could play a role in the trophic transfer of the toxin into shellfish. During a field study at a single location in southern England, we confirmed C. simula DNA in seawater adjacent to trestle-farmed Pacific oysters Magallana gigas (formerly Crassostrea gigas) with a history of TTX occurrence. C. simula DNA in seawater was significantly higher in June and July during the active phase of toxin accumulation compared to periods of either no or continually decreasing TTX concentrations in M. gigas. In addition, C. simula DNA was detected in oyster digestive glands collected on 15 June 2021, the day with the highest recorded C. simula DNA abundance in seawater. These findings show evidence of a relationship between C. simula and TTX occurrence, providing support for the hypothesis that bivalves may acquire TTX through filter-feeding on microscopic life forms of C. simula present in the water column at particular periods each year. Although further evidence is needed to confirm such feeding activity, this study significantly contributes to discussions about the biological source of TTX in European bivalve shellfish.

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Perfetto, Rosa, Sonia Del Prete, Daniela Vullo, Giovanni Sansone, Carmela Barone, Mosè Rossi, Claudiu Supuran et Clemente Capasso. « Sequence Analysis, Kinetic Constants, and Anion Inhibition Profile of the Nacrein-Like Protein (CgiNAP2X1) from the Pacific Oyster Magallana gigas (Ex-Crassostrea gigas) ». Marine Drugs 15, n^o 9 (28 août 2017) : 270. http://dx.doi.org/10.3390/md15090270.

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Guy, C., A. Blight, D. Smyth et D. Roberts. « The world is their oyster : Differences in epibiota on sympatric populations of native Ostrea edulis and non-native Crassostrea gigas (Magallana gigas) oysters ». Journal of Sea Research 140 (octobre 2018) : 52–58. http://dx.doi.org/10.1016/j.seares.2018.07.002.

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Cho, In Kyu, Bong-Seung Seo, So-Yeon Hwang, Ye-In Lee, Ji-Sung Moon, Su-Jin Park, Hee-Jung Lee, Young Baek Hur et Youn Hee Choi. « The Annual Reproductive Cycle, Proximate Composition, Fatty Acid and Amino Acid Content of Pacific Oyster, Crassostrea gigas (Magallana gigas), in Gadeok-do, Korea ». Development & ; Reproduction 27, n^o 3 (septembre 2023) : 101–15. http://dx.doi.org/10.12717/dr.2023.27.3.101.

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Shulkin, V. M., et V. Ya Kavun. « Long-term Monitoring of Pollution of the Coastal Water Area of Ussuriysk Bay with Metals : Case Study of “Green” Oysters Magallana gigas ; (= Crassostrea gigas) (Thunberg, 1793) ». Биология моря 49, n^o 2 (1 mars 2023) : 105–13. http://dx.doi.org/10.31857/s0134347523020079.

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In September 2021, the content of heavy metals Pb, Cu, Cd, Zn, Ni, Fe, and Mn was estimated in the tissues of the oyster Magallana gigas (= Crassostrea gigas) (Thunberg, 1793) and in the silty fraction of bottom sediments from mollusk habitats in coastal waters around the Muravyov-Amursky Peninsula, including the most polluted area off the western coast of Ussuri Bay of the Sea of Japan. It has been shown that, despite the reclamation of the landfill located here in 2010, being the main source of metal pollution, copper is present in high concentrations in bottom sediments and tissues of oysters, giving them a green color. The mollusks living in this area also retain a high concentration of zinc. The concentrations of Pb, Cd, and Ni in oyster tissues over the past 20 years have decreased by 2–5 times in accordance with the decrease in the number of mobile forms of these metals in bottom sediments; however, they are still 3–6 times higher than regional estimates for polluted water areas. With abnormal accumulation of copper, manganese, on the contrary, demonstrates a decrease in the concentration in the tissues of oysters from the most polluted stations, reflecting the deterioration of the physiological state of mollusks. The results obtained indicate the need to continue the remediation of the western coast of Ussuri Bay and monitor the pollution of coastal waters with metals.

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Ruesink, J. L., K. Houle, E. Beck, F. C. Boardman, A. Suhrbier et B. Hudson. « Intertidal Grow-Out Technique, Not Eelgrass (Zostera marina), Influences Performance of Pacific Oysters (Magallana gigas) ». Aquaculture Research 2023 (16 novembre 2023) : 1–13. http://dx.doi.org/10.1155/2023/6621043.

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Colocation of farmed shellfish in seagrass, although not permitted in some regions of the USA, has been proposed as a means to reach cobenefits of habitat and food production. Seagrass could benefit bivalves through protection from predation or abiotic stressors but conversely can reduce water flow and food delivery. At 10 farm sites in Washington state (USA), we tested the performance of Pacific oysters (Magallana (Crassostrea) gigas) grown in ground culture or off-bottom culture across a range of seagrass densities. Oysters averaged 32 m−2 and 30% shell cover on ground culture beds. Oysters in off-bottom culture showed a negative relationship between size and density across beds, consistent with growth and mortality through the crop cycle, and the largest oysters were at densities similar to ground culture. Within each farm site, ground and off-bottom beds were selected with each of three categories of seagrass (none, sparse, dense). Dense seagrass on aquaculture beds was half the density of nearby unfarmed seagrass beds. For outplanted oysters over 3–9 months, many aspects of oyster performance improved when oysters were elevated above the sediment. Relative to ground culture, off-bottom oysters had better survival (85% vs. 69%), 7% larger size, and 48% higher condition after 3 months in summer, and the survival advantages persisted over winter. Oyster survival on-bottom was especially impaired in finer sediment. No oyster performance differences were associated with seagrass, except for 9-month results, available for five of 10 farms. After 9 months at these five farms, oyster survival showed a small negative effect of dense seagrass, and shell size showed a small positive effect of sparse seagrass. Consequently, seagrass may not provide a boost to colocated intertidal shellfish, but we found little evidence of trade-offs in which maintaining seagrass would reduce yield of farmed oysters. Moving oysters out of the boundary layer and away from soft sediment improves both survival and tissue growth aspects of yield.

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Ajani, Penelope A., Chowdhury Sarowar, Alison Turnbull, Hazel Farrell, Anthony Zammit, Stuart Helleren, Gustaaf Hallegraeff et Shauna A. Murray. « A Comparative Analysis of Methods (LC-MS/MS, LC-MS and Rapid Test Kits) for the Determination of Diarrhetic Shellfish Toxins in Oysters, Mussels and Pipis ». Toxins 13, n^o 8 (11 août 2021) : 563. http://dx.doi.org/10.3390/toxins13080563.

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Rapid methods for the detection of biotoxins in shellfish can assist the seafood industry and safeguard public health. Diarrhetic Shellfish Toxins (DSTs) are produced by species of the dinoflagellate genus Dinophysis, yet the comparative efficacy of their detection methods has not been systematically determined. Here, we examined DSTs in spiked and naturally contaminated shellfish–Sydney Rock Oysters (Saccostrea glomerata), Pacific Oysters (Magallana gigas/Crassostrea gigas), Blue Mussels (Mytilus galloprovincialis) and Pipis (Plebidonax deltoides/Donax deltoides), using LC-MS/MS and LC-MS in 4 laboratories, and 5 rapid test kits (quantitative Enzyme-Linked Immunosorbent Assay (ELISA) and Protein Phosphatase Inhibition Assay (PP2A), and qualitative Lateral Flow Assay (LFA)). We found all toxins in all species could be recovered by all laboratories using LC-MS/MS (Liquid Chromatography—tandem Mass Spectrometry) and LC-MS (Liquid Chromatography—Mass Spectrometry); however, DST recovery at low and mid-level concentrations (<0.1 mg/kg) was variable (0–150%), while recovery at high-level concentrations (>0.86 mg/kg) was higher (60–262%). While no clear differences were observed between shellfish, all kits delivered an unacceptably high level (25–100%) of falsely compliant results for spiked samples. The LFA and the PP2A kits performed satisfactorily for naturally contaminated pipis (0%, 5% falsely compliant, respectively). There were correlations between spiked DSTs and quantitative methods was highest for LC-MS (r2 = 0.86) and the PP2A kit (r2 = 0.72). Overall, our results do not support the use of any DST rapid test kit as a stand-alone quality assurance measure at this time.

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Gilson, Abby R., Neil E. Coughlan, Jaimie T. A. Dick et Louise Kregting. « Marine heat waves differentially affect functioning of native (Ostrea edulis) and invasive (Crassostrea [Magallana] gigas) oysters in tidal pools ». Marine Environmental Research 172 (décembre 2021) : 105497. http://dx.doi.org/10.1016/j.marenvres.2021.105497.

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Bruhns, Torben, Stefan Timm, Nina Feußner, Sonja Engelhaupt, Matthias Labrenz, Mathias Wegner et Inna M. Sokolova. « Combined effects of temperature and emersion-immersion cycles on metabolism and bioenergetics of the Pacific oyster Crassostrea (Magallana) gigas ». Marine Environmental Research 192 (novembre 2023) : 106231. http://dx.doi.org/10.1016/j.marenvres.2023.106231.

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Tian, Haijuan, et Changjiao Liu. « Preserving Raw Oysters with High Hydrostatic Pressure and Irradiation Technology ». Sustainability 15, n^o 19 (7 octobre 2023) : 14557. http://dx.doi.org/10.3390/su151914557.

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Refrigerated raw oysters, including Pacific oysters (Magallana gigas), eastern oysters (Crassostrea virginica), and European flat oysters (Ostrea edulis), are popular seafood products. Pathogenic contamination and spoilage during storage and transport limit their shelf life. High hydrostatic pressure (HHP) and irradiation effectively reduce pathogens and spoilage microorganisms in raw oysters while preserving their taste and texture. This review article presents a comprehensive analysis of the use of HHP and irradiation as sanitation methods for raw oysters, incorporating findings from geographical distribution, mathematical modeling, and radiation quality’s impact on sterilization efficacy. The results demonstrate that untreated eastern oysters can maintain a total bacterial count below the recommended limit of 107 CFU/g for only 2–3 weeks at 5 °C, and are at risk of harboring pathogens such as Vibrio spp. and norovirus. HHP treatment at 600 MPa and irradiation treatment at 2 kGy can effectively reduce the pathogen load in raw oysters. However, supplementary measures such as additional cleaning or lower temperatures are required to prolong the shelf life of treated raw oysters to 2–3 weeks. Taken together, the application of HHP and irradiation to raw oyster sanitation represents a promising approach for enhancing the safety and quality of this beloved seafood delicacy.

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Shulkin, V. M., et V. Ya Kavun. « Long-Term Monitoring of Pollution of the Coastal Water Area of Ussuri Bay with Metals : A Case Study of “Green” Oysters Magallana gigas (= Crassostrea gigas) (Thunberg, 1793) ». Russian Journal of Marine Biology 49, n^o 2 (avril 2023) : 97–105. http://dx.doi.org/10.1134/s1063074023020074.

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Potts, Robert W. A., Tim Regan, Stuart Ross, Kelly Bateman, Chantelle Hooper, Richard Paley, Ross D. Houston et Tim P. Bean. « Laboratory Replication of Ostreid Herpes Virus (OsHV-1) Using Pacific Oyster Tissue Explants ». Viruses 16, n^o 8 (22 août 2024) : 1343. http://dx.doi.org/10.3390/v16081343.

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Pacific oysters (Crassostrea or Magallana gigas) are one of the most economically important aquaculture species globally. Over the past two decades, ostreid herpesvirus (OsHV-1) has become a major pathogen of cultured Pacific oysters, resulting in widespread mortality with a global distribution. Experimental use of OsHV-1 is challenging for many reasons, including both complexity of host–pathogen dynamics and a lack of functioning model systems. The goal of this study was to improve the tools available for working with OsHV-1 in both whole animals and in tissue explants established from oysters maintained in controlled laboratory conditions. Tissue explants were taken from oysters originating from two different sources that have different levels of mortality in experimental OsHV-1 infections and were exposed to OsHV-1. A whole-animal infection experiment was run concurrently as a comparison. Quantitative PCR and electron microscopy were used to confirm that the explants were capable of replicating OsHV-1. Furthermore, the quantitative PCR results suggest that the source of the oysters was significant in determining the outcome of infection in the explants, supporting the validity of the explant model for OsHV-1 infection. This tissue explant approach for studying OsHV-1 allows for the control of confounding factors in the disease outcome that is not possible in whole-animal experiments, providing a new tool for the study of OsHV-1 in Pacific oysters.

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Bergström, Per, Linnea Thorngren, Åsa Strand et Mats Lindegarth. « Identifying high‐density areas of oysters using species distribution modeling : Lessons for conservation of the native Ostrea edulis and management of the invasive Magallana ( Crassostrea ) gigas in Sweden ». Ecology and Evolution 11, n^o 10 (22 mars 2021) : 5522–32. http://dx.doi.org/10.1002/ece3.7451.

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Chiefa, Francesco, Paola Tedeschi, Mirco Cescon, Valentina Costa, Leonardo Aguiari et Luisa Pasti. « Comparative analysis of two different immersion times in the farming systems for Ostrea edulis and Magallana (Crassostrea) gigas in a brackish basin of Valli di Comacchio (northern Italy) ». Aquaculture 598 (mars 2025) : 742009. https://doi.org/10.1016/j.aquaculture.2024.742009.

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Yasuoka, Noriko, Ryo Nakayama et Hirotaka Tsujimura. « Wild Spat Collection from the Pacific Oyster Crassostrea ; (Magallana) gigas ; (Thunberg, 1793) in Osaka Bay, Japan, Using Plastic Bottles ». Sessile Organisms 41, n^o 2 (20 décembre 2024) : 27–31. https://doi.org/10.4282/sosj.41.27.

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Markert, Alexandra. « How dense is dense ? Toward a harmonized approach to characterizing reefs of non-native Pacific oysters – with consideration of native mussels ». NeoBiota 57 (29 mai 2020) : 7–52. http://dx.doi.org/10.3897/neobiota.57.49196.

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Pacific oysters Crassostrea (Magallana) gigas have been successfully invading ecosystems worldwide. As an ecosystem engineer, they have the potential to substantially impact on other species and on functional processes of invaded ecosystems. Engineering strength depends on oyster density in space and time. Density has not yet been studied on the extent of reef structural dynamics. This study assessed abundance of naturalized Pacific oysters by shell length (SL) of live individuals and post-mortem shells at six sites over six consecutive years during post-establishment. Individual biomass, i.e. live wet mass (LWM), flesh mass (FM) and live shell mass (SM LIVE), were determined from a total of 1.935 live oysters in order to estimate areal biomass. The generic term density attribute was used for SL-related population categories and the biomass variables LWM, FM, SM LIVE and SM. As the oyster invasion modulated resident Mytilus edulis beds, the study was supplemented by contemporaneously assessed data of mussels and corresponding analyses. Interrelations of abundance and areal biomass revealed distinct linkages between specific density attributes. Most importantly, large individuals were identified as intrinsic drivers for the determination of areal biomass. Additionally, allometry of large oysters differed from small oysters by attenuated scaling relations. This effect was enhanced by oyster density as results showed that crowding forced large individuals into an increasing slender shape. The significant relationship between the density attributes large oyster and biomass enabled a classification of reef types by large oyster abundance. Reef type (simple or complex reef) and oyster size (small or large) were considered by implementing a novel concept of weighted twin functions (TF) for the relationship between SL and individual biomass. This study demonstrates that the interplay of scaling parameters (scalar, exponent) is highly sensitive to the estimation of individual biomass (shape) and that putative similar scaling parameters can exceedingly affect the estimation of areal biomass. For the first time, this study documents the crucial relevance of areal reference, i.e. cluster density (CD) or reef density (RD), when comparing density. RD considers reef areas devoid of oysters and results from CD reduced by reef coverage (RC) as the relative reef area occupied by oysters. A compilation of density attributes at simple and complex reefs shall serve as a density guide. Irrespective of areal reference, oyster structural density attributes were significantly higher at complex than at simple reefs. In contrast, areal reference was of vital importance when evaluating the impact of engineering strength at ecosystem-level. While mussel CD was similar at both reef types, RD at complex reefs supported significantly more large mussels and higher mussel biomass than at simple reefs. Although mussels dominated both reef types by abundance of large individuals, oysters were the keystone engineers by dominating biomass. The prominent status of large oysters for both allometric scaling and density, presumably characteristic for Pacific oyster populations worldwide, should be considered when conducting future investigations. The effort of monitoring will substantially be reduced as only large oysters have to be counted for an empirical characterization of Pacific oyster reefs. The large oyster concept is independent of sampling season, assessment method or ecosystem, and is also applicable to old data sets. Harmonization on the proposed density attributes with a clear specification of areal reference will allow trans-regional comparisons of Pacific oyster reefs and will facilitate evaluations of engineering strength, reef performance and invasional impacts at ecosystem-level.

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Hwang, Soyeon, Su-Jin Park, Josel Cadangin, Bong-Seung Seo, Yein Lee et Youn H. Choi. « The involvement of GSK3β for glycogen synthesis throughout the annual cycle of Pacific oyster, Crassostrea gigas (Magallana gigas) ». Israeli Journal of Aquaculture - Bamidgeh 75 (6 janvier 2023). http://dx.doi.org/10.46989/001c.67818.

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Crassostrea gigas is a frequently studied species in understanding physiological processes in bivalves. Similar to other animals, oysters store glucose in the body as glycogen. Glycogen is known to supply energy for germ cell development and maintenance. Glycogen is synthesized by glycogen synthase. GSK3β regulates glycogen synthase activity and plays an important role in glycogen synthesis. Therefore, this study aims to examine the effect of GSK3β on the annual cycle of oysters and the glycogen synthesis pathway and to investigate the energy pathway in comparison with seasonal variation. Oysters were sampled monthly for one year and were subjected to glycogen content, RT-PCR, FISH, and western blot analysis. The year-round glycogen content significantly differs only in the mantle edge during spring and summer of both sexes but not in labial palp, digestive gland, gonad, and adductor muscle. The expression of GSK3β mRNA level was highest in October for females and April for males. Both sexes had the lowest expression in July. In the adductor muscle, females and males showed the highest expression in April and the lowest in July and October. The pattern of GSK3β expression in gonads and adductor muscle was similarly confirmed through FISH. As a result of examining the signaling system, p-GSK3β (serine 9) increased. At the same time, glycogen synthase decreased in May when the condition index was the highest, p-GSK3β decreased in October and July when spawning occurred, and glycogen synthase increased. Overall, it is thought that p-GSK3β expression is high in C. gigas at ripe, which inhibits glycogen synthesis and is used as energy for growth and maturation. Glycogen synthesis occurs for energy storage during degeneration.

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Stechele, Brecht, Marie Maar, Jeroen Wijsman, Dimitry Van der Zande, Steven Degraer, Peter Bossier et Nancy Nevejan. « Comparing life history traits and tolerance to changing environments of two oyster species (Ostrea edulis and Crassostrea gigas) through Dynamic Energy Budget theory ». Conservation Physiology 10, n^o 1 (1 janvier 2022). http://dx.doi.org/10.1093/conphys/coac034.

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Abstract To predict the response of the European flat oyster (Ostrea edulis) and Pacific cupped oyster (Crassostrea gigas/Magallana gigas) populations to environmental changes, it is key to understand their life history traits. The Dynamic Energy Budget (DEB) theory is a mechanistic framework that enables the quantification of the bioenergetics of development, growth and reproduction from fertilization to death across different life stages. This study estimates the DEB parameters for the European flat oyster, based on a comprehensive dataset, while DEB parameters for the Pacific cupped oyster were extracted from the literature. The DEB parameters for both species were validated using growth rates from laboratory experiments at several constant temperatures and food levels as well as with collected aquaculture data from the Limfjorden, Denmark, and the German Bight. DEB parameters and the Arrhenius temperature parameters were compared to get insight in the life history traits of both species. It is expected that increasing water temperatures due to climate change will be beneficial for both species. Lower assimilation rates and high energy allocation to soma explain O. edulis’ slow growth and low reproductive output. Crassostrea gigas’ high assimilation rate, low investment in soma and extremely low reserve mobility explains the species’ fast growth, high tolerance to starvation and high reproductive output. Hence, the reproductive strategies of both species are considerably different. Flat oysters are especially susceptible to unfavourable environmental conditions during the brooding period, while Pacific oysters’ large investment in reproduction make it well adapted to highly diverse environments. Based on the life history traits, aquaculture and restoration of O. edulis should be executed in environments with suitable and stable conditions.

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Morga, Benjamin, Mickäel Mège, Nicole Faury, Lionel Dégremont, Bruno Petton, Jean-François Pépin, Tristan Renault et Caroline Montagnani. « Antiviral protection in the Pacific oyster Crassostrea (Magallana) gigas against OsHV-1 infection using UV-inactivated virus ». Frontiers in Marine Science 11 (23 avril 2024). http://dx.doi.org/10.3389/fmars.2024.1378511.

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The increase of the frequency and severity of marine diseases affecting farmed marine mollusks are currently threatening the sustainability of this aquaculture sector, with few available prophylactic or therapeutic solutions. Recent advances have shown that the innate immune system of invertebrates can develop memory mechanisms allowing for efficient protection against pathogens. These properties have been called innate immune memory, immune priming or trained immunity. Previous results demonstrated the possibility to elicit antiviral immune priming to protect Pacific oysters against the ostreid herpes virus 1 (OsHV-1), currently plaguing M. gigas production worldwide. Here, we demonstrate that UV-inactivated OsHV-1 is also a potent elicitor of immune priming. Previous exposure to the inactivated virus was able to efficiently protect oysters against OsHV-1, significantly increasing oyster survival. We demonstrate that this exposure blocked viral replication and was able to induce antiviral gene expression potentially involved in controlling the infection. Finally, we show that this phenomenon can persist for at least 3 months, suggesting the induction of innate immune memory mechanisms. This study unravels new ways to train the Pacific oyster immune system that could represent an opportunity to develop new prophylactic strategies to improve health and to sustain the development of marine mollusk aquaculture.

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Teixeira Alves, Mickael, Nick G. H. Taylor et Hannah J. Tidbury. « Understanding drivers of wild oyster population persistence ». Scientific Reports 11, n^o 1 (9 avril 2021). http://dx.doi.org/10.1038/s41598-021-87418-1.

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AbstractPersistence of wild Pacific oyster, Magallana gigas, also known as Crassostrea gigas, has been increasingly reported across Northern European waters in recent years. While reproduction is inhibited by cold waters, recent warm summer temperature has increased the frequency of spawning events. Although correlation between the increasing abundance of Pacific oyster reefs in Northern European waters and climate change is documented, persistence of wild populations may also be influenced by external recruitment from farmed populations and other wild oyster populations, as well as on competition for resources with aquaculture sites. Our understanding of the combined impact of the spawning frequency, external recruitment, and competition on wild population persistence is limited. This study applied an age-structured model, based on ordinary differential equations, to describe an oyster population under discrete temperature-related dynamics. The impact of more frequent spawning events, external recruitment, and changes in carrying capacity on Pacific oyster density were simulated and compared under theoretical scenarios and two case studies in Southern England. Results indicate that long term persistence of wild oyster populations towards carrying capacity requires a high frequency of spawning events but that in the absence of spawning, external recruitment from farmed populations and other wild oyster populations may act to prevent extinction and increase population density. However, external recruitment sources may be in competition with the wild population so that external recruitment is associated with a reduction in wild population density. The implications of model results are discussed in the context of wild oyster population management.

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Schmidlin, Sarah, Clea Parcerisas, Jeroen Hubert, Maryann S. Watson, Jan Mees, Dick Botteldooren, Paul Devos, Elisabeth Debusschere et Pascal I. Hablützel. « Comparison of the effects of reef and anthropogenic soundscapes on oyster larvae settlement ». Scientific Reports 14, n^o 1 (31 mai 2024). http://dx.doi.org/10.1038/s41598-024-63322-2.

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AbstractSettlement is a critical period in the life cycle of marine invertebrates with a planktonic larval stage. For reef-building invertebrates such as oysters and corals, settlement rates are predictive for long-term reef survival. Increasing evidence suggests that marine invertebrates use information from ocean soundscapes to inform settlement decisions. Sessile marine invertebrates with a planktonic stage are particularly reliant on environmental cues to direct them to ideal habitats. As gregarious settlers, oysters prefer to settle amongst members of the same species. It has been hypothesized that oyster larvae from species Crassostrea virginica and Ostrea angasi use distinct conspecific oyster reef sounds to navigate to ideal habitats. In controlled laboratory experiments we exposed Pacific Oyster Magallana gigas larvae to anthropogenic sounds from conspecific oyster reefs, vessels, combined reef-vessel sounds as well as off-reef and no speaker controls. Our findings show that sounds recorded at conspecific reefs induced higher percentages of settlement by about 1.44 and 1.64 times compared to off-reef and no speaker controls, respectively. In contrast, the settlement increase compared to the no speaker control was non-significant for vessel sounds (1.21 fold), combined reef-vessel sounds (1.30 fold), and off-reef sounds (1.18 fold). This study serves as a foundational stepping stone for exploring larval sound feature preferences within this species.

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Vignier, Julien, Matthew Reardon, Megan Exton, Lizenn Delisle, Anne Rolton, Emmanuel Malpot, Megan Scholtens et al. « Comparative performance of selected triploid oysters Crassostrea (Magallana) gigas, produced by chemical induction and mated triploid techniques, to their diploid counterparts ». Aquaculture, novembre 2024, 741894. http://dx.doi.org/10.1016/j.aquaculture.2024.741894.

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Waser, Andreas M., Dagmar Lackschewitz, Jeffrey Knol, Karsten Reise, K. Mathias Wegner et David W. Thieltges. « Spread of the invasive shell-boring annelid Polydora websteri (Polychaeta, Spionidae) into naturalised oyster reefs in the European Wadden Sea ». Marine Biodiversity 50, n^o 5 (5 août 2020). http://dx.doi.org/10.1007/s12526-020-01092-6.

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Abstract With globally growing aquaculture activities, the co-introduction of parasites alongside large-scale movements of commercial species poses an increasing risk for marine ecosystems. Here, we present the first record of the shell-boring polychaete Polydora websteri Hartman in Loosanoff and Engle, 1943 in invasive Pacific oysters Crassostrea (Magallana) gigas (Thunberg, 1793) in the European Atlantic Ocean. In October 2014, mud blisters in the shells of wild Pacific oysters and specimens of a spionid polychaete were observed in close proximity to a commercial oyster farm at the island of Sylt (Germany) in the European Wadden Sea. Subsequent investigations indicated that these blisters only occurred near the farm and that no other mollusc species were affected. Morphological and molecular analysis identified the polychaete as Polydora websteri, a species that nowadays widely occurs around the globe, but likely is native to the Asian Pacific. Later sampling activities detected P. websteri also at other locations around Sylt as well as in the Dutch part of the Wadden Sea at the island of Texel. The number of polychaetes in the oysters was, however, relatively low and mostly below 10 individuals per oyster. Together, this evidence suggests that P. websteri is currently extending its range. As the introduction of P. websteri may have severe ecological and economic implications, this study aims to alert others to look for P. websteri at Western European coasts within farmed or wild Pacific oysters to further document its spread.

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Sutherland, Ben J. G., Neil F. Thompson, Liam B. Surry, Krishna Reddy Gujjula, Claudio D. Carrasco, Srinivas Chadaram, Spencer L. Lunda et al. « An amplicon panel for high-throughput and low-cost genotyping of Pacific oyster ». G3 : Genes, Genomes, Genetics, 13 juin 2024. http://dx.doi.org/10.1093/g3journal/jkae125.

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Abstract Maintaining genetic diversity in cultured shellfish can be challenging due to high variance in individual reproductive success, founder effects, and rapid genetic drift, but is important to retain adaptive potential and avoid inbreeding depression. To support broodstock management and selective breeding in cultured Pacific oysters (Crassostrea (Magallana) gigas), we developed an amplicon panel targeting 592 genomic regions and SNP variants with an average of 50 amplicons per chromosome. Target SNPs were selected based on elevated observed heterozygosity or differentiation in Pacific oyster populations in British Columbia, Canada. The use of the panel for parentage applications was evaluated using multiple generations of oysters from a breeding program on Vancouver Island, Canada (n = 181) and families selected for Ostreid herpesvirus-1 resistance from the Molluscan Broodstock Program in Oregon, USA (n = 136). Population characterization was evaluated using wild, naturalized, farmed, or hatchery oysters sampled throughout the Northern Hemisphere (n = 190). Technical replicates showed high genotype concordance (97.5%; n = 68 replicates). Parentage analysis found suspected pedigree and sample handling errors, demonstrating the panel’s value for quality control in breeding programs. Suspected null alleles were identified and found to be largely population dependent, suggesting population-specific variation impacting target amplification. Null alleles were identified using existing data without the need for pedigree information, and once they were removed, assignment rates increased to 93.0% and 86.0% of possible assignments in the two breeding program datasets. A pipeline for analyzing the amplicon sequence data from sequencer output, amplitools, is also provided.

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Li, Yiqian, Wenyan Nong, Tobias Baril, Ho Yin Yip, Thomas Swale, Alexander Hayward, David E. K. Ferrier et Jerome H. L. Hui. « Reconstruction of ancient homeobox gene linkages inferred from a new high-quality assembly of the Hong Kong oyster (Magallana hongkongensis) genome ». BMC Genomics 21, n^o 1 (15 octobre 2020). http://dx.doi.org/10.1186/s12864-020-07027-6.

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Abstract Background Homeobox-containing genes encode crucial transcription factors involved in animal, plant and fungal development, and changes to homeobox genes have been linked to the evolution of novel body plans and morphologies. In animals, some homeobox genes are clustered together in the genome, either as remnants from ancestral genomic arrangements, or due to coordinated gene regulation. Consequently, analyses of homeobox gene organization across animal phylogeny provide important insights into the evolution of genome organization and developmental gene control, and their interaction. However, homeobox gene organization remains to be fully elucidated in several key animal ancestors, including those of molluscs, lophotrochozoans and bilaterians. Results Here, we present a high-quality chromosome-level genome assembly of the Hong Kong oyster, Magallana hongkongensis (2n = 20), for which 93.2% of the genomic sequences are contained on 10 pseudomolecules (~ 758 Mb, scaffold N50 = 72.3 Mb). Our genome assembly was scaffolded using Hi-C reads, facilitating a larger scaffold size compared to the recently published M. hongkongensis genome of Peng et al. (Mol Ecol Resources, 2020), which was scaffolded using the Crassostrea gigas assembly. A total of 46,963 predicted gene models (45,308 protein coding genes) were incorporated in our genome, and genome completeness estimated by BUSCO was 94.6%. Homeobox gene linkages were analysed in detail relative to available data for other mollusc lineages. Conclusions The analyses performed in this study and the accompanying genome sequence provide important genetic resources for this economically and culturally valuable oyster species, and offer a platform to improve understanding of animal biology and evolution more generally. Transposable element content is comparable to that found in other mollusc species, contrary to the conclusion of another recent analysis. Also, our chromosome-level assembly allows the inference of ancient gene linkages (synteny) for the homeobox-containing genes, even though a number of the homeobox gene clusters, like the Hox/ParaHox clusters, are undergoing dispersal in molluscs such as this oyster.

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Pfennings, Kai, Tom K. Hoffmann, Jan Hitzegrad, Maike Paul, Nils Goseberg et Achim Wehrmann. « Beyond annual metrics : Linking seasonal population dynamics to vertical oyster reef growth ». Ecology and Evolution 14, n^o 9 (septembre 2024). http://dx.doi.org/10.1002/ece3.70238.

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AbstractOysters are ecosystem engineering species building reef‐like biogenic structures in temperate shallow water environments, serving as biodiversity hotspots. Recently, also their ecosystem services such as fish nursery, pollutants sink and self‐sustaining coastal protection mechanisms came into a research focus. In light of accelerated sea level rise and increasing environmental dynamics, a determination of vertical growth rates of these biosedimentary structures is paramount in assessing their resilience. This study embarked on a comprehensive survey of seasonal vertical reef growth rates using terrestrial laser scanning and related population dynamics of two intertidal reefs built by the non‐native oyster Magallana gigas in the Wadden Sea. We quantified median reef growth at 19.8 mm yr−1 for the Kaiserbalje reef and 17.5 mm yr−1 for the Nordland reef. Additionally, we tested the hypothesis that the seasonal variations in reef growth rates correspond to the local population dynamics, mainly the parameters of shell length and abundance which mirror delayed effects from previous spawning events. Shell growth rates were 0.03–0.06 mm d−1 in winter and 0.10–0.16 mm d−1 in summer, mean oyster abundance from autumn 2019 to spring 2022 was 627 ± 43 ind. m−2 and 338 ± 87 ind. m−2 at the Kaiserbalje and Nordland reefs respectively. Minor reef growth in the topmost reef area reflects an emerging equilibrium of the vertical reef position to actual sea level. Our findings are in accordance with growth of natural Crassostrea virginica reefs on the US East Coast, indicating potential resilience to actual and predicted sea level rise scenarios. Moreover, understanding local hydro‐morphodynamic feedback linked to sea level rise will be vital in predicting the three‐dimensional stability of these biosedimentary structures and habitats.

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Zhong, Kevin Xu, Amy M. Chan, Brenna Collicutt, Maxim Daspe, Jan F. Finke, Megan Foss, Timothy J. Green et al. « The prokaryotic and eukaryotic microbiome of Pacific oyster spat is shaped by ocean warming but not acidification ». Applied and Environmental Microbiology, 11 mars 2024. http://dx.doi.org/10.1128/aem.00052-24.

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ABSTRACT Pacific oysters ( Magallana gigas, a.k.a. Crassostrea gigas ), the most widely farmed oysters, are under threat from climate change and emerging pathogens. In part, their resilience may be affected by their microbiome, which, in turn, may be influenced by ocean warming and acidification. To understand these impacts, we exposed early-development Pacific oyster spat to different temperatures (18°C and 24°C) and p CO 2 levels (800, 1,600, and 2,800 µatm) in a fully crossed design for 3 weeks. Under all conditions, the microbiome changed over time, with a large decrease in the relative abundance of potentially pathogenic ciliates ( Uronema marinum ) in all treatments with time. The microbiome composition differed significantly with temperature, but not acidification, indicating that Pacific oyster spat microbiomes can be altered by ocean warming but is resilient to ocean acidification in our experiments. Microbial taxa differed in relative abundance with temperature, implying different adaptive strategies and ecological specializations among microorganisms. Additionally, a small proportion (~0.2% of the total taxa) of the relatively abundant microbial taxa were core constituents (>50% occurrence among samples) across different temperatures, p CO 2 levels, or time. Some taxa, including A4b bacteria and members of the family Saprospiraceae in the phyla Chloroflexi (syn. Chloroflexota ) and Bacteroidetes (syn. Bacteroidota ), respectively, as well as protists in the genera Labyrinthula and Aplanochytrium in the class Labyrinthulomycetes , and Pseudoperkinsus tapetis in the class Ichthyosporea were core constituents across temperatures, p CO 2 levels, and time, suggesting that they play an important, albeit unknown, role in maintaining the structural and functional stability of the Pacific oyster spat microbiome in response to ocean warming and acidification. These findings highlight the flexibility of the spat microbiome to environmental changes. IMPORTANCE Pacific oysters are the most economically important and widely farmed species of oyster, and their production depends on healthy oyster spat. In turn, spat health and productivity are affected by the associated microbiota; yet, studies have not scrutinized the effects of temperature and p CO 2 on the prokaryotic and eukaryotic microbiomes of spat. Here, we show that both the prokaryotic and, for the first time, eukaryotic microbiome of Pacific oyster spat are surprisingly resilient to changes in acidification, but sensitive to ocean warming. The findings have potential implications for oyster survival amid climate change and underscore the need to understand temperature and p CO 2 effects on the microbiome and the cascading effects on oyster health and productivity.

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Cao, A., MA Travers, T. Varela et A. Villalba. « The utility of selective breeding to increase resistance against OsHV-1 µVar for Pacific oyster Crassostrea (Magallana) gigas farming in Galicia is called into question by infection with Vibrio aestuarianus ». Diseases of Aquatic Organisms, 2025. https://doi.org/10.3354/dao03838.

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