The Experts below are selected from a list of 2118 Experts worldwide ranked by ideXlab platform
John A. Nell - One of the best experts on this subject based on the ideXlab platform.
-
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...
-
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.
-
The use of the oyster Saccostrea glomerata as a biomonitor of trace metal contamination: intra-sample, local scale and temporal variability and its implications for biomonitoring
Journal of Environmental Monitoring, 2005Co-Authors: Wayne Robinson, John A. Nell, William A. Maher, Frank Krikowa, Rosalind E. HandAbstract:Cu, Cd, Zn, Pb and Se concentrations were measured in the bivalve mollusc Saccostrea glomerata (Iredale and Roughly) from two uncontaminated locations, Clyde River Estuary, Batemans Bay and Moona Moona Creek, Jervis Bay, to determine natural variability of metals associated with mass, gender, age, tissue type and site within location. Trace metals were also measured in the Clyde River Estuary over an 11 year period and in five other NSW estuaries (Hastings River, Hunter River, Georges River, Tillgerry Creek and Lake Pambula) over a 13-month period to determine temporal variability and if diploid and triploid oysters accumulate trace metals differently. There were few significant relationships between trace metal concentrations and mass and no significant differences in trace metal concentrations between female and male oysters. Younger oysters (1.3 years) had significantly higher copper concentrations and higher trace metal variability than mature oysters (3 years). Different tissues have different trace metal concentrations with muscle tissues having lower concentrations. Considerable inherent variability occurs in oyster cohorts. Analysing specific tissues did not reduce variability of trace metal concentrations. Comparison of trace metal concentrations at two sites within the Clyde Estuary showed a significant difference in zinc concentrations. Cu, Cd, Zn and Se concentrations were generally higher and less variable in triploids than diploids. Pb had a variable pattern of accumulation with no consistent elevation in diploids or triploids. Inter annual variability of trace metal concentrations was considerable and trace metal concentrations also fluctuated throughout an annual cycle with no clear seasonal trends. Measurement of trace metals at known contaminated locations showed that Saccostrea glomerata accumulates metals in response to contamination. Saccostrea glomerata meet most of the requirements to be a biomonitor of trace metal contamination as they are abundant, sessile/sedentary, easy to identify, provide sufficient tissue for analysis, and accumulate trace metals in response to contamination. However, as trace metal concentrations can vary with mass, age, estuary position, ploidy type and temporally, care must be taken to collect individual organisms of similar mass, age and ploidy type to minimise variability, and from similar consistent positions and times to allow for seasonal changes in environmental conditions. Trace metal concentration variability is higher in young animals, thus to reduce variability, older mature animals could be selected. However, with immature oysters there are no complications because of the effects of spawning i.e. sudden loss of trace metals or body mass.
-
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.
-
Third generation evaluation of Sydney rock oyster Saccostrea commercialis (Iredale and Roughley) breeding lines
Aquaculture, 1999Co-Authors: John A. Nell, Ian R. Smith, A.k. SheridanAbstract:The progeny of four breeding lines of Sydney rock oysters, Saccostrea commercialis, selected for faster growth over two generations, were compared with controls in an 18-month farming experiment. Mean whole weights of oysters from all four selection lines did not differ significantly from each other but, were significantly greater (P
Wayne A Oconnor - One of the best experts on this subject based on the ideXlab platform.
-
the evaluation of twelve algal species as food for juvenile sydney rock oysters Saccostrea commercialis iredale roughley
Aquaculture, 1992Co-Authors: Wayne A Oconnor, John A. Nell, John A. DiemarAbstract:Juvenile Sydney rock oysters (Saccostrea commercialis) were fed diets composed of either one of twelve algal species or one of eleven algal species in combination with Skeletonema costatum. When used as the sole diet for 21 days, the diatoms Skeletonema costatum, Chaetoceros calcitrans. Chaetoceros gracilis and Thalassiosira pseudonana produced the greatest live weight increase in spat. When Skeletonema costatum was fed in combination with the remaining eleven algal species for 19 days, diets including Chaetoceros gracilis, Tetraselmis chui and Tetraselmis suecica produced the highest live weight increases. These findings indicated differences in the food value of several algal species to larvae and spat of the Sydney rock oyster.
-
the evaluation of fresh algae and stored algal concentrates as a food source for sydney rock oyster Saccostrea commercialis iredale roughley larvae
Aquaculture, 1991Co-Authors: John A. Nell, Wayne A OconnorAbstract:Abstract Six algal species were fed singly and in combination with Pavlova lutheri , in both fresh and concentrated form, to 1-day-old Sydney rock oyster, Saccostrea commercialis , larvae for 6 days. Although a number of algal species produced high larval length increases, the best fresh diet consisted of P. lutheri and Isochrysis aff. galbana (T-iso). However, when concentrated to a paste and stored for 7–14 days at 4 °C, a combination of P. lutheri and Chaetoceros calcitrans produced greater length increases than any other fresh or stored, single or combined diet tested. Centrifugation and storage of algae prior to feeding had varied effects on the algal species tested, but it had no detected deleterious effects on any of the diatoms tested.
John A. Diemar - One of the best experts on this subject based on the ideXlab platform.
-
The evaluation of twelve algal species as food for juvenile Sydney rock oysters Saccostrea commercialis (Iredale & Roughley)
Aquaculture, 1992Co-Authors: Wayne A. O'connor, John A. Nell, John A. DiemarAbstract:Juvenile Sydney rock oysters (Saccostrea commercialis) were fed diets composed of either one of twelve algal species or one of eleven algal species in combination with Skeletonema costatum. When used as the sole diet for 21 days, the diatoms Skeletonema costatum, Chaetoceros calcitrans. Chaetoceros gracilis and Thalassiosira pseudonana produced the greatest live weight increase in spat. When Skeletonema costatum was fed in combination with the remaining eleven algal species for 19 days, diets including Chaetoceros gracilis, Tetraselmis chui and Tetraselmis suecica produced the highest live weight increases. These findings indicated differences in the food value of several algal species to larvae and spat of the Sydney rock oyster.
-
the evaluation of twelve algal species as food for juvenile sydney rock oysters Saccostrea commercialis iredale roughley
Aquaculture, 1992Co-Authors: Wayne A Oconnor, John A. Nell, John A. DiemarAbstract:Juvenile Sydney rock oysters (Saccostrea commercialis) were fed diets composed of either one of twelve algal species or one of eleven algal species in combination with Skeletonema costatum. When used as the sole diet for 21 days, the diatoms Skeletonema costatum, Chaetoceros calcitrans. Chaetoceros gracilis and Thalassiosira pseudonana produced the greatest live weight increase in spat. When Skeletonema costatum was fed in combination with the remaining eleven algal species for 19 days, diets including Chaetoceros gracilis, Tetraselmis chui and Tetraselmis suecica produced the highest live weight increases. These findings indicated differences in the food value of several algal species to larvae and spat of the Sydney rock oyster.
David A Raftos - One of the best experts on this subject based on the ideXlab platform.
-
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.
-
Next generation sequence analysis of the transcriptome of Sydney rock oysters (Saccostrea glomerata) exposed to a range of environmental stressors.
Marine genomics, 2014Co-Authors: Sharon E Hook, Emma L Johnston, Sham Nair, Anthony C Roach, Philippe Moncuquet, Natalie A Twine, David A RaftosAbstract:Sydney rock oysters (Saccostrea glomerata) were exposed to environmental stressors at contaminated field sites or in a controlled laboratory setting. RNA seq transcriptome data were generated for the gill and digestive gland using Roche's 454 pyrosequencing technology. 28,685 contigs were de novo assembled which encoded 11,671 different protein products. The data will act as a reference for future studies in ecology, immunology and environmental toxicology.
-
sydney rock oyster Saccostrea glomerata hemocytes morphology and function
Journal of Invertebrate Pathology, 2007Co-Authors: Saleem Aladaileh, Sham V Nair, Debra Birch, David A RaftosAbstract:In this study, three major hemocyte types were identified in the Sydney rock oyster. They were characterized primarily by light and electron microscopy based on the presence or absence of granules and nucleus to cytoplasm ratios. Hemoblast-like cells were the smallest cell type 4.0 ± 0.4 μm and comprised 15 ± 3% of the hemocyte population. They had large nuclei and scanty basic cytoplasm. This cell type also had some endoplasmic reticuli and mitochondria. The second major type were hyalinocytes. Hyalinocytes represented 46 ± 6% of all hemocytes. They were large cells (7.1 ± 1.0 μm) that had low nucleus:cytoplasm ratios and agranular basic or acidic cytoplasm. Hyalinocytes had the ability to phagocytose yeast cells and formed the core of hemocyte aggregates associated with agglutination. Four discrete sub-populations of hyalinocytes were identified. The third major cell type were the granulocytes, comprising 38 ± 1% of the hemocyte population. These cells were large (9.3 ± 0.3 μm) and were characterized by cytoplasm containing many acidic or basic granules. Granulocytes were more phagocytic than hyalinocytes and they formed the inner layer of hemocytes during the encapsulation of fungal hyphae. Five discrete sub-populations of granulocytes were identified based on the types of granules in their cytoplasm. Flow cytometry showed that the hemocytes of rock oysters could be divided into between two and four major cell types based on their light scattering properties. The most common of the cell types identified by flow cytometry corresponded to hyalinocytes and granulocytes. Cytochemical assays showed that most enzymes associated with immunological activity were localized in granulocytes. Their granules contained acid phosphatase, peroxidase, phenoloxidase, superoxide and melanin. Hyalinocytes were positive only for acid phosphatase. All of these observations suggest that Sydney rock oysters have a broad variety of functionally specialized hemocytes, many of which are involved in host defense.
-
Phenoloxidase-associated cellular defence in the Sydney rock oyster, Saccostrea glomerata, provides resistance against QX disease infections.
Developmental and Comparative Immunology, 2007Co-Authors: Daniel Butt, David A RaftosAbstract:The enzyme phenoloxidase is a critical component of the immunological defence of invertebrates. Previously, we have shown that the activity of phenoloxidase in Sydney rock oysters (Saccostrea glomerata) correlates with the severity of QX disease outbreaks. The aetiological agent of QX disease is the opportunistic protozoan parasite, Marteilia sydneyi. In this study, we examined the response of oyster haemocytes to challenge with M. sydneyi. Granular haemocytes were able to rapidly phagocytose parasite sporonts. Phagocytosis stimulated intracellular associated phenoloxidase activity that led to the complete melanisation of phagosomes. Significant differences in phagocytic indexes and phenoloxidase activities were observed between oysters selected for resistance to QX disease (QXR) and non-selected wild-type oysters. The data suggest that phagocytosis and cellular melanisation are critical defensive responses of Sydney rock oysters infected with M. sydneyi.
R. Ubrhien - One of the best experts on this subject based on the ideXlab platform.
-
Metal concentrations in waters, sediments and biota of the far south-east coast of New South Wales, Australia, with an emphasis on Sn, Cu and Zn used as marine antifoulant agents
Environmental Geochemistry and Health, 2019Co-Authors: I. R. Mcvay, W. A. Maher, F. Krikowa, R. UbrhienAbstract:Tin, Cu, Zn, Cd, Pb, Ag and Hg concentrations were measured in waters, sediments and three ubiquitous sedentary molluscs: the oyster, Saccostrea glomerata , a rocky intertidal gastropod, Austrocochlea porcata , and a sediment-dwelling gastropod, Batillaria australis , at 12 locations along the far south coast of NSW, Australia, from Batemans Bay to Twofold Bay during 2009. Metal concentrations in water for Sn, Cd, Ag and Hg were below detection limits (
