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Wayne A Oconnor - One of the best experts on this subject based on the ideXlab platform.
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dynamics of the Sydney Rock Oyster microbiota before and during a qx disease event
Aquaculture, 2021Co-Authors: Viet Khue Nguyen, Wayne A Oconnor, Michael Dove, William L King, Nachshon Siboni, Khandaker Rayhan Mahbub, Justin R Seymour, Hafizur Rahman, Cheryl Jenkins, Maurizio LabbateAbstract:Abstract The Sydney Rock Oyster (SRO; Saccostrea glomerata) is the most intensively farmed Oyster species in Australia however, Queensland unknown (QX) disease has resulted in substantial losses and impeded productivity. QX disease is caused by infection with the parasite Marteilia Sydneyi, and like other diseases, outbreaks are driven by a series of complex environmental and host factors such as seasonality, seawater salinity and Oyster genetics. A potential but understudied factor in QX disease is the SRO microbiota, which we sought to examine before and during a QX disease outbreak. Using 16S rRNA (V1 – V3 region) amplicon sequencing, we examined the microbiota of SROs deployed in an estuary where QX disease occurs, with sampling conducted fortnightly over 22 weeks. Marteilia Sydneyi was detected in the SROs by PCR (QX-positive), 16 weeks after the first sampling event and sporonts were observed in the digestive gland two weeks later on. There were no apparent patterns observed between the microbiota of QX-positive SROs with and without digestive gland sporonts however, the microbiota of QX-positive SROs was significantly different from those sampled prior to detection of M. Sydneyi and from those negative for M. Sydneyi post detection. As a result, shifts in microbiota structure occurred before sporulation in the digestive gland and either before or shortly after pathogen colonisation. The microbiota shifts associated with QX-positive Oysters were principally driven by a relative abundance increase of operational taxonomic units (OTUs) assigned to unclassified species of the Borrelia and Candidatus Hepatoplasma genera and a relative abundance decrease in an OTU assigned to an unclassified species of the Mycoplasma genus. Since Mycoplasma species are common microbiota features of SROs and other Oysters, we propose that there may be an important ecological link between Mycoplasma species and the health state of SROs.
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the Sydney Rock Oyster microbiota is influenced by location season and genetics
Aquaculture, 2020Co-Authors: Viet Khue Nguyen, Wayne A Oconnor, Michael Dove, William L King, Nachshon Siboni, Khandaker Rayhan Mahbub, Justin R Seymour, Maurizio LabbateAbstract:Abstract Queensland unknown (QX) disease is a significant cause of economic loss for the Sydney Rock Oyster (SRO) aquaculture industry. Evidence is emerging that QX disease is multi-factorial in nature, with a number of environmental and host factors contributing to disease dynamics. Efforts to mitigate the impacts of QX disease are primarily focused on breeding for disease resistance however, the mechanisms that drive disease resistance are poorly understood. One potential factor influencing disease resistance is the microbiota. To determine the influence of location, season and disease resistance on the SRO microbiota, we used 16S rRNA (V1 – V3 region) amplicon sequencing. The microbiota of six SRO families with two categorised as QX-resistant and four as QX-susceptible, deployed to two different locations (Port Stephens and Wallis Lake, NSW, Australia) and over two seasons (Austral summer and winter), were characterised. As expected, the SRO microbiota was distinct to the microbial community found in seawater. Further, the SRO microbiota was significantly influenced by location and season, with operational taxonomic units (OTUs) assigned to the Candidatus Hepatoplasma and Endozoicomonas genera identified as significant drivers of microbiota dissimilarity between locations and seasons. Disease resistance also significantly influenced the SRO microbiota but only at the winter time point which is before the typical QX disease period. Overall, OTUs assigned to the Mycoplasma, Borrelia and Endozoicomonas genera were over-represented in QX-resistant SRO microbiota, whereas members of the Pseudoalteromonas, Vibrio, and Candidatus Hepatoplasma genera were over-represented in QX-sensitive microbiota. These findings confirm the influencing role of location and season on the microbiota structure as evidenced in other molluscan species, but also provide preliminary evidence that the microbiota assemblage before the QX disease period may be important for resistance to disease and may provide new avenues for managing SRO aquaculture in the future.
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bioavailability of polycyclic aromatic compounds pacs to the Sydney Rock Oyster saccostrea glomerata from sediment matrices of an economically important australian estuary
Science of The Total Environment, 2020Co-Authors: Oluyoye Idowu, Wayne A Oconnor, Thi Kim Anh Tran, Phil Baker, Hazel Farrel, Anthony Zammit, Kirk T Semple, Palanisami ThavamaniAbstract:Improving risk assessment and remediation rests on better understanding of contaminant bioavailability. Despite their strong toxicological attributes, little is known about the partitioning behaviour and bioavailability of polar polycyclic aromatic hydrocarbons (PAHs) in aquatic environments. The present study provides an insight into the bioavailable fractions of polar PAHs and their parent analogues in the tissues of the Sydney Rock Oyster, Saccostrea glomerata, a model aquatic bio-indicator organism. The concentration and distribution patterns of parent and polar PAHs including oxygenated PAHs (oxyPAHs), nitrated PAHs (NPAHs) and heterocyclic PAHs (HPAHs) were determined in water, sediment and Oysters from an ecologically and economically important estuary of New South Wales, Australia. Total concentrations of PAHs, oxyPAHs, NPAHs and HPAHs were higher in sediments compared to Oyster tissue and water. For most polar PAHs, total concentrations for water, sediment and Oyster samples were 1). BSAF individual computation showed that bioaccumulation of nine investigated HPAHs in Oyster tissues were relatively low and only 2-EAQ (oxyPAH) and 1N-NAP (NPAH) showed high levels of accumulation in Oyster tissues, similar to parent PAHs. To the best of our knowledge, this is the first known study on the bioavailability of polar and non-polar PAHs in an Australian aquatic environment. The outcome of this study might be a useful indicator of the potential risks of polar PAHs to humans and other living organisms.
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parental exposure to the synthetic estrogen 17α ethinylestradiol ee2 affects offspring development in the Sydney Rock Oyster saccostrea glomerata
Environmental Pollution, 2020Co-Authors: Rafiquel Islam, Wayne A Oconnor, Thi Kim Anh Tran, Megan Andrewpriestley, Frederic D L Leusch, Geoff R MacfarlaneAbstract:Very little is currently known regarding the effects of estrogenic endocrine disrupting chemicals on embryonic and larval development in molluscs, nor the potential effects of parental (F0) exposure on resultant F1 offspring. In this study, we assessed the embryotoxic impacts of exposure to environmentally relevant concentrations of the synthetic estrogen, 17α-ethinylestradiol (EE2), to male and female parents (50 ng/L) and their offspring (5 and 50 ng/L) in the native Australian Sydney Rock Oyster, Saccostrea glomerata. There were no detectable effects of parental exposure on fertilisation success, proportions of early larval (F1) morphs and unfertilised eggs. Offspring impacts were evidenced in terms of developmental delays, with decreased percentages of D-veligers retained by 45 μm mesh, along with a reduction of swimming capabilities of larvae at 2 days post-fertilisation (dpf) when both parents had been exposed to 50 ng/L EE2. Although no significant parental effects were found on the survival of F1 larvae at 9 dpf, retardation of shell growth was observed on F1 larvae in treatments where both parents had been exposed to 50 ng/L EE2. Subsequent larval exposure from 2 to 9 dpf caused declines in survival and reduction of shell length in F1 larvae at both 5 and 50 ng/L EE2 across all parental exposure treatments. Collectively, parental EE2 imparts effects on offspring in terms of retardation of larval development, and subsequent offspring exposure to EE2 further exacerbates impacts to development. Future research should aim to understand the potential mechanisms of EE2 induced toxicity and its transmission resulting in altered phenotypes of the F1 generation.
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characterisation of the metallothionein gene in the Sydney Rock Oyster and its expression upon metal exposure in Oysters with different prior metal exposure histories
Marine Environmental Research, 2019Co-Authors: Thanvapon Yingprasertchai, Wayne A Oconnor, Thi Kim Anh Tran, Richard Y C Kong, Geoff R MacfarlaneAbstract:The metal-binding protein metallothionein (MT) is widely used as a biomarker of metal contamination. In this study, we cloned a MT gene (sgMT) from the Sydney Rock Oyster Saccostrea glomerata. The gene encodes a MT-I protein with a classical αβ domain structure and is expressed as two transcripts resulting from alternative polyadenylation. The gene promoter contains two putative metal-responsive elements (MREs) which are known to be required for metal-inducible transcription. A specific and efficient qPCR assay was developed to quantify sgMT mRNA expression. Further, we assessed whether prior metal exposure history influences sgMT mRNA expression upon subsequent metal exposure. Oysters with varying prior metal exposure histories (contaminated and reference) were exposed to Cu, Cd and Zn. Expression of sgMT generally increased with metal dose, and Oysters with an elevated past metal exposure history exhibited higher sgMT expression under Cd and Zn stress, representing a potential acclimatory response to prior metal exposure.
John A. Nell - One of the best experts on this subject based on the ideXlab platform.
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Farming the Sydney Rock Oyster (Saccostrea commercialis) in Australia
Reviews in Fisheries Science, 2008Co-Authors: John A. NellAbstract:Abstract Commercial production of Sydney Rock Oysters (Saccostrea commercialis) in Australia began simultaneously in New South Wales (NSW) and southern Queensland around 1870. It began with the exploitation of dredge beds, intertidal Oyster beds, and with the placement of a range of catching and growing substrates such as sticks, slabs of Rocks, and shell placed on intertidal mud flats. As dredge beds were depleted and problems with accumulation of silt and mudworm (Polydora sp.) increased, the industry progressively adopted the stick and tray culture on intertidal racks. However, the use of sticks for growing is now rapidly diminishing as farmers are learning to scrape small (4 to 8 mm) spat off sticks and grow them in specially adapted trays or other growing containers (single‐seed culture). At its peak in 1976–1977, the combined NSW and southern Queensland industry produced 9267 t (wet weight including shell) or 154,454 bags (1200 Oysters per bag), but it has declined over the last decade to a producti...
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evaluation of the progeny of the fourth generation Sydney Rock Oyster saccostrea glomerata gould 1850 breeding lines for resistance to qx disease marteilia Sydneyi and winter mortality bonamia roughleyi
Aquaculture Research, 2006Co-Authors: Michael Dove, John A. Nell, Wayne A OconnorAbstract:A breeding program for Sydney Rock Oysters Saccostrea glomerata (Gould, 1850) has been selecting Oysters for resistance to QX disease (Marteilia Sydneyi) and winter mortality (Bonamia roughleyi) for three generations at three sites in Georges River, New South Wales, Australia. The experimental sites are located at the upper, middle and lower reaches of Oyster growing areas in the estuary. QX disease mainly occurs in the middle and upper reaches and is most severe at the latter. Winter mortality on the other hand occurs mainly at the lower and middle reaches and is most severe at the former. Progeny of third-generation Sydney Rock Oyster breeding lines were evaluated for resistance to both QX disease and winter mortality against a non-selected control. Line 1, selected for QX disease resistance at the upper estuary site, had excellent resistance to one season of exposure to disease, but suffered high mortality during the second season of exposure. However, these Oysters had already reached market size of 50 g whole weight, with low mortality at 2 years of age, before the second episode of QX disease. Line 2 showed good improvement in resistance to both diseases, whereas Line 3, was the most resistant to winter mortality. Selection for resistance to QX disease did not appear to confer resistance to winter mortality and the converse also applied.
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Evaluation of progeny of fourth generation Sydney Rock Oyster Saccostrea glomerata (Gould, 1850) breeding lines
Aquaculture Research, 2005Co-Authors: John A. Nell, Ben PerkinsAbstract:The progeny of four 4th generation Sydney Rock Oyster Saccostrea glomerata (Gould, 1850) breeding lines that were selected for fast growth were compared in a 3-year farming experiment. Oysters of the most improved breeding line (line 2) reached market size (≥50-g whole weight) 15 months earlier than non-selected control Oysters (3 years and 5 months). The average reduction in time to market size for Oysters of all four breeding lines was 12.5 months.
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evaluation of the progeny of second generation Sydney Rock Oyster saccostrea glomerata gould 1850 breeding lines for resistance to qx disease marteilia Sydneyi
Aquaculture, 2003Co-Authors: John A. Nell, Rosalind E. HandAbstract:Abstract The progeny of second-generation Sydney Rock Oyster Saccostrea glomerata (Gould, 1850) breeding lines were tested for resistance to QX disease Marteilia Sydneyi against a non-selected control. Mortality was reduced from 85.7±1.5% for the controls to 63.5±1.2% for the most improved breeding line. This is a reduction in mortality of 22% after only two generations of selection. These partially QX disease-resistant Oysters in which M. Sydneyi was found were also 21% heavier than controls. Selection for resistance to M. Sydneyi is feasible and may be improved through further selection.
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Food value of live yeasts and dry yeast-based diets fed to Sydney Rock Oyster Saccostrea commercialis spat
Aquaculture, 1996Co-Authors: John A. Nell, John A. Diemar, Mike HeasmanAbstract:Abstract Six yeast species, cultured on both glucose and acetate as carbon sources, and three dry yeast-based diets (Microfeast ® ) were compared as potential algae substitutes for feeding Sydney Rock Oyster spat. At the 80% substitution level, two of the dry yeast-based diets containing 7.6 and 21.5% total lipid gave 72 and 76%, respectively, of the dry spat weight gain obtained with the algae-fed control. Weight gains of 58–67% of that of the algae-fed control were also obtained with the following live yeast diets: Dipodascus capitatus and Candida utilis cultured on either glucose or acetate, and Saccharomyces cerevisiae cultured on glucose. There was a negative correlation between the increase in spat dry weight and nitrogen free extract ( r = −0.58; y = 30.34 − 0.26 x ; P r = 0.51; y = 6.10 + 0.31 x ; P
David A Raftos - One of the best experts on this subject based on the ideXlab platform.
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The genome of the Oyster Saccostrea offers insight into the environmental resilience of bivalves
DNA Research, 2018Co-Authors: Daniel Powell, Wayne A. O'connor, David A Raftos, Sankar Subramanian, Saowaros Suwansa-ard, Min Zhao, Abigail ElizurAbstract:Oysters are keystone species in estuarine ecosystems and are of substantial economic value to fisheries and aquaculture worldwide. Contending with disease and environmental stress are considerable challenges to Oyster culture. Here we report a draft genome of the Sydney Rock Oyster, Saccostrea glomerata, an iconic and commercially important species of edible Oyster in Australia known for its enhanced resilience to harsh environmental conditions. This is the second reference genome to be reported from the family Ostreidae enabling a genus-level study of lophotrochozoan genome evolution. Our analysis of the 784-megabase S. glomerata genome shows extensive expansions of gene families associated with immunological non-self-recognition. Transcriptomic analysis revealed highly tissue-specific patterns of expression among these genes, suggesting a complex assortment of immune receptors provide this Oyster with a unique capacity to recognize invading microbes. Several gene families involved in stress response are notably expanded in Saccostrea compared with other Oysters, and likely key to this species' adaptations for improved survival higher in the intertidal zone. The Sydney Rock Oyster genome provides a valuable resource for future research in molluscan biology, evolution and environmental resilience. Its close relatedness to Crassostrea will further comparative studies, advancing the means for improved Oyster agriculture and conservation.
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Progress on the Genome Characterisation of the Sydney Rock Oyster (Saccostrea glomerata)
2017Co-Authors: Daniel Powell, Wayne A. O'connor, David A Raftos, Abigail ElizurAbstract:The Sydney Rock Oyster (Saccostrea glomerata) is considered a delicacy in restaurants worldwide and is an economically important cultured marine species in Australia. For the last century, Oyster farming has been the most valuable aquaculture industry in the state of New South Wales, where the production of S. glomerata can reach over USD$26 million per year. Contending with disease and environmental stress are considerable challenges to Oyster culture and the manipulation of reproductive condition is vital for production and marketing. However, like many other shellfish, little is known of the molecular mechanisms underpinning these traits. The generation of a high quality draft genome can offer insights into these mechanisms, however, it also presents difficulties due to the high levels of heterozygosity and repetitiveness seen in Oysters. Here we present a draft S. glomerata genome using over 300X coverage of illumina small insert paired-end and mate-pair libraries with an additional Chicago library and HiRise scaffolding from Dovetail Genomics. The draft assembly has a total sequence length of 788 Mb, a scaffold number of 10,107 with an N50 of 804 Kb. Ongoing efforts include refining gene models using RNA-Seq data from a range of different tissues. The draft genome will serve as a platform to support genetic breeding programs and has already begun to facilitate further research investigating the influence of neuropeptides in the regulation of reproduction.
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biomarkers of winter mortality resistance in selectively bred Sydney Rock Oysters saccostrea glomerata
Aquaculture, 2016Co-Authors: Vineet Vaibhav, David A Raftos, Emma L Thompson, Maxime Lepretre, Paul A HaynesAbstract:Sydney Rock Oysters (Saccostrea glomerata) are an important part of Australian cuisine and are considered to be a gourmet delicacy for their distinctive flavor. The species is native to Australian estuaries where it faces challenges from environmental stressors and human impacts. In addition, the Sydney Rock Oyster aquaculture industry has been periodically affected by outbreaks of diseases such as Queensland Unknown (QX) disease and Winter Mortality, a protozoan borne disease greatly impacting the production of the Sydney Rock Oyster industry. These diseases limit the production of Sydney Rock Oysters but do not affect other major Oyster species farmed in New South Wales. Winter Mortality is a protozoan born disease affecting the production of the Sydney Rock Oyster industry greatly. Over the past few decades, breeding lines of Sydney Rock Oysters have been selected for resistance to Winter Mortality and Queensland Unknown disease. In this study, we report a proteomic comparison between the Winter Mortality selective breeding line and hatchery control Oysters. We identified 22 protein features showing differential intensities between the two proteomes. The identities of 19 of these features were established using nanoflow liquid chromatography-tandem mass spectrometry. The differential proteome identified in the current study coincides well with previous analyses of stress responses in Oysters, suggesting commonalities between intracellular reactions to disease and stress. For instance, cytoskeletal effects found in the current study to be associated with Winter Mortality resistance have been previously linked to intracellular stress responses. In addition, we identified novel proteins such as proteasome subunit alpha type-6 and calcium-dependent protein kinase 31, both of which are reported for the first time in disease resistant Sydney Rock Oysters. Results of this study will add to our understanding of stress responses and provide the first proteomic survey of Winter Mortality resistance in Sydney Rock Oysters.
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a proteomic analysis of the effects of metal contamination on Sydney Rock Oyster saccostrea glomerata haemolymph
Aquatic Toxicology, 2011Co-Authors: Emma L Thompson, Sham V Nair, G F Birch, Daisy A Taylor, Paul A Haynes, David A RaftosAbstract:The current study uses proteomics to assess the effects of metal contamination on Sydney Rock Oyster haemolymph. Saccostrea glomerata were exposed in aquaria for four days to three environmentally relevant metals (copper, lead or zinc). Oyster haemolymph proteins from metal-exposed Oysters were then compared to haemolymph from non-exposed controls using 2-dimensional electrophoresis to identify proteins that differed significantly in intensity. These proteins were then subjected to tandem mass spectrometry so that putative protein identities could be assigned. The data suggest that there are unique protein expression profiles for each metal. Exposure to 100 μg/l of copper, lead or zinc yielded a total of 25 differentially expressed proteins. However, only one of these protein spots exhibited altered intensities in response to all three metals. Eighteen of the 25 spots were significantly affected by just one of the three metals. Differentially expressed proteins were assigned to five different categories of biological function. Proteins affecting shell properties were the most common functional group accounting for 34% of the identified proteins. Cytoskeletal activities and metabolism/stress responses each accounted for a further 25% of the proteins.
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Disease prevention strategies for QX disease (Marteilia Sydneyi) of Sydney Rock Oysters (Saccostrea glomerata)
Journal of Shellfish Research, 2011Co-Authors: Timothy J Green, Wayne A. O'connor, David A Raftos, Robert D. Adlard, Andrew C. BarnesAbstract:The Sydney Rock Oyster (Saccostrea glomerata) forms the basis of an important aquaculture industry on the east coast of Australia. During the 1970s, production of S. glomerata began to decline, in part as a result of mortalities arising from Queensland unknown (QX) disease. Histological studies implicated the paramyxean parasite Marteilia Sydneyi in the disease outbreaks. Disease zoning was implemented to prevent the spread of M. Sydneyi-infected Oysters. This control measure hindered Rock Oyster farming, which historically has relied on transferring wild-caught spat between estuaries for on-growing to market size and has not prevented the subsequent occurrence of QX disease in the Georges and Hawkesbury rivers in central New South Wales. Management of QX disease has been hampered by the complicated life cycle of M. Sydneyi, with outbreaks of QX disease likely to be regulated by a combination of the abundance of intermediate host of M. Sydneyi, environmental stressors, and the immunocompetence of S. glomerata. The future of the Sydney Rock Oyster industry relies on understanding these factors and progressing the industry from relying on farming wild-caught seed to the successful commercialization of hatchery-produced QX-resistant S. glomerata.
Michael Dove - One of the best experts on this subject based on the ideXlab platform.
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dynamics of the Sydney Rock Oyster microbiota before and during a qx disease event
Aquaculture, 2021Co-Authors: Viet Khue Nguyen, Wayne A Oconnor, Michael Dove, William L King, Nachshon Siboni, Khandaker Rayhan Mahbub, Justin R Seymour, Hafizur Rahman, Cheryl Jenkins, Maurizio LabbateAbstract:Abstract The Sydney Rock Oyster (SRO; Saccostrea glomerata) is the most intensively farmed Oyster species in Australia however, Queensland unknown (QX) disease has resulted in substantial losses and impeded productivity. QX disease is caused by infection with the parasite Marteilia Sydneyi, and like other diseases, outbreaks are driven by a series of complex environmental and host factors such as seasonality, seawater salinity and Oyster genetics. A potential but understudied factor in QX disease is the SRO microbiota, which we sought to examine before and during a QX disease outbreak. Using 16S rRNA (V1 – V3 region) amplicon sequencing, we examined the microbiota of SROs deployed in an estuary where QX disease occurs, with sampling conducted fortnightly over 22 weeks. Marteilia Sydneyi was detected in the SROs by PCR (QX-positive), 16 weeks after the first sampling event and sporonts were observed in the digestive gland two weeks later on. There were no apparent patterns observed between the microbiota of QX-positive SROs with and without digestive gland sporonts however, the microbiota of QX-positive SROs was significantly different from those sampled prior to detection of M. Sydneyi and from those negative for M. Sydneyi post detection. As a result, shifts in microbiota structure occurred before sporulation in the digestive gland and either before or shortly after pathogen colonisation. The microbiota shifts associated with QX-positive Oysters were principally driven by a relative abundance increase of operational taxonomic units (OTUs) assigned to unclassified species of the Borrelia and Candidatus Hepatoplasma genera and a relative abundance decrease in an OTU assigned to an unclassified species of the Mycoplasma genus. Since Mycoplasma species are common microbiota features of SROs and other Oysters, we propose that there may be an important ecological link between Mycoplasma species and the health state of SROs.
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the Sydney Rock Oyster microbiota is influenced by location season and genetics
Aquaculture, 2020Co-Authors: Viet Khue Nguyen, Wayne A Oconnor, Michael Dove, William L King, Nachshon Siboni, Khandaker Rayhan Mahbub, Justin R Seymour, Maurizio LabbateAbstract:Abstract Queensland unknown (QX) disease is a significant cause of economic loss for the Sydney Rock Oyster (SRO) aquaculture industry. Evidence is emerging that QX disease is multi-factorial in nature, with a number of environmental and host factors contributing to disease dynamics. Efforts to mitigate the impacts of QX disease are primarily focused on breeding for disease resistance however, the mechanisms that drive disease resistance are poorly understood. One potential factor influencing disease resistance is the microbiota. To determine the influence of location, season and disease resistance on the SRO microbiota, we used 16S rRNA (V1 – V3 region) amplicon sequencing. The microbiota of six SRO families with two categorised as QX-resistant and four as QX-susceptible, deployed to two different locations (Port Stephens and Wallis Lake, NSW, Australia) and over two seasons (Austral summer and winter), were characterised. As expected, the SRO microbiota was distinct to the microbial community found in seawater. Further, the SRO microbiota was significantly influenced by location and season, with operational taxonomic units (OTUs) assigned to the Candidatus Hepatoplasma and Endozoicomonas genera identified as significant drivers of microbiota dissimilarity between locations and seasons. Disease resistance also significantly influenced the SRO microbiota but only at the winter time point which is before the typical QX disease period. Overall, OTUs assigned to the Mycoplasma, Borrelia and Endozoicomonas genera were over-represented in QX-resistant SRO microbiota, whereas members of the Pseudoalteromonas, Vibrio, and Candidatus Hepatoplasma genera were over-represented in QX-sensitive microbiota. These findings confirm the influencing role of location and season on the microbiota structure as evidenced in other molluscan species, but also provide preliminary evidence that the microbiota assemblage before the QX disease period may be important for resistance to disease and may provide new avenues for managing SRO aquaculture in the future.
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Heatwaves alter survival of the Sydney Rock Oyster, Saccostrea glomerata
Marine Pollution Bulletin, 2020Co-Authors: Elliot Scanes, Laura M. Parker, Wayne A. O'connor, Michael Dove, Pauline M. RossAbstract:Abstract Heatwaves are an increasing threat to organisms across the globe. Marine and atmospheric heatwaves are predicted to impact sessile intertidal marine organisms, especially when exposed at low tide and unable to seek refuge. The study aimed to determine whether a simulated atmospheric heatwave will alter the survival of selectively bred families of Sydney Rock Oysters (Saccostrea glomerata), and whether survival is dependent on morphological and physiological traits. The survival of S. glomerata families to a simulated atmospheric heatwave varied from 25 to 60% and was not correlated with morphology or physiology. Survival may depend on the presence of genotypes that translate into molecular defenses such as heat-shock proteins and inhibitor of apoptosis proteins that provide Oysters with resilience. Understanding the responses among families of Oysters to heatwaves is critical if we are to restore the ecological services of Oyster reefs and sustain Oyster aquaculture.
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can genetic diversity be maintained across multiple mass selection lines of Sydney Rock Oyster saccostrea glomerata despite loss within each
Aquaculture, 2016Co-Authors: Wayne A Oconnor, Michael Dove, Wayne KnibbAbstract:This study assesses the genetic diversity of four different hatchery bred lines of Sydney Rock Oyster, Saccosstrea glomerata (SRO) after three, five and seven generations of mass selection using microsatellite DNA markers and mitochondrial cytochrome C oxidase subunit 1 sequences (COX1). This was achieved using seven newly developed microsatellite markers, along with three published loci. Considering the same number of samples in each line, the number of different alleles in each of the four hatchery lines ranged from 49 to 70 alleles from 10 loci, which was approximate 50% less than the 120 alleles found in the samples from the wild population. However, if we pool all our four hatchery lines together, then their total number of alleles was not significantly different from the wild population. Similar to the patterns found for the DNA microsatellite alleles, mtDNA haplotype numbers were considerably lower in each of the hatchery lines than in the samples from the wild population. Again, pooling the hatchery lines gave a total haplotype number not statistically significantly different from that in the samples from the wild. Considering together the DNA microsatellite alleles and the mtDNA haplotypes, we conclude that there was a substantial loss of genetic diversity within all lines separately over generations of mass selection, and that such mass selection was not sustainable in the long term. However, importantly, these data indicate that for Oysters, if multiple independent mass selection lines are kept, then their combined genetic diversity may approach that of the ancestral line or wild population even after many generations of mass selection. These results for Oysters, finding preservation of diversity among lines yet loss within them, are similar to recent findings for multiple banana shrimp lines; considering both species together it suggests that one relatively simple option suitable for some farms and industry to maintain genetic diversity during mass selection over many generations of selection is to subdivide their breeding nucleus and keep multiple different and independent lines over generations. It remains to be tested if this approach is general across many aquaculture species and circumstances.
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evaluation of the progeny of the fourth generation Sydney Rock Oyster saccostrea glomerata gould 1850 breeding lines for resistance to qx disease marteilia Sydneyi and winter mortality bonamia roughleyi
Aquaculture Research, 2006Co-Authors: Michael Dove, John A. Nell, Wayne A OconnorAbstract:A breeding program for Sydney Rock Oysters Saccostrea glomerata (Gould, 1850) has been selecting Oysters for resistance to QX disease (Marteilia Sydneyi) and winter mortality (Bonamia roughleyi) for three generations at three sites in Georges River, New South Wales, Australia. The experimental sites are located at the upper, middle and lower reaches of Oyster growing areas in the estuary. QX disease mainly occurs in the middle and upper reaches and is most severe at the latter. Winter mortality on the other hand occurs mainly at the lower and middle reaches and is most severe at the former. Progeny of third-generation Sydney Rock Oyster breeding lines were evaluated for resistance to both QX disease and winter mortality against a non-selected control. Line 1, selected for QX disease resistance at the upper estuary site, had excellent resistance to one season of exposure to disease, but suffered high mortality during the second season of exposure. However, these Oysters had already reached market size of 50 g whole weight, with low mortality at 2 years of age, before the second episode of QX disease. Line 2 showed good improvement in resistance to both diseases, whereas Line 3, was the most resistant to winter mortality. Selection for resistance to QX disease did not appear to confer resistance to winter mortality and the converse also applied.
Rosalind E. Hand - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the progeny of second generation Sydney Rock Oyster saccostrea glomerata gould 1850 breeding lines for resistance to qx disease marteilia Sydneyi
Aquaculture, 2003Co-Authors: John A. Nell, Rosalind E. HandAbstract:Abstract The progeny of second-generation Sydney Rock Oyster Saccostrea glomerata (Gould, 1850) breeding lines were tested for resistance to QX disease Marteilia Sydneyi against a non-selected control. Mortality was reduced from 85.7±1.5% for the controls to 63.5±1.2% for the most improved breeding line. This is a reduction in mortality of 22% after only two generations of selection. These partially QX disease-resistant Oysters in which M. Sydneyi was found were also 21% heavier than controls. Selection for resistance to M. Sydneyi is feasible and may be improved through further selection.
