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Tristan Renault - One of the best experts on this subject based on the ideXlab platform.
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detection and distribution of ostreid herpesvirus 1 in experimentally infected pacific Oyster spat
2016Co-Authors: Amelie Segarra, Nicole Faury, Laury Baillon, Delphine Tourbiez, Tristan RenaultAbstract:High mortality rates are reported in spat and Larvae of Pacific Oyster Crassostrea gigas and associated with ostreid herpesvirus 1 (OsHV-1) detection in France. Although the viral infection has been experimentally reproduced in Oyster Larvae and spat, little knowledge is currently available concerning the viral entry and its distribution in organs and tissues. This study compares OsHV-1 DNA and RNA detection and localization in experimentally infected Oysters using two virus doses: a low dose that did not induce any mortality and a high dose inducing high mortality. Real time PCR demonstrated significant differences in terms of viral DNA amounts between the two virus doses. RNA transcripts were detected in Oysters receiving the highest dose of viral suspension whereas no transcript was observed in Oysters injected with the low dose. This study also allowed observing kinetics of viral DNA and RNA detection in different tissues of Oyster spat. Finally, viral detection was significantly different in function of tissues (p 0.005), time (p 0.005) with an interaction between tissues and time (p 0.005) for each probe.
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detection of ostreid herpesvirus 1 oshv 1 by pcr using a rapid and simple method of dna extraction from Oyster Larvae
2005Co-Authors: Frederico M Batista, Nicolas Taris, Pierre Boudry, Tristan RenaultAbstract:A DNA extraction procedure was developed for the detection of ostreid herpesvirus-1 (OsHV-1) using the polymerase chain reaction (PCR) in Oyster Larvae. The DNA extraction procedure developed was tested on 8 larval samples. Abnormal nuclei with characteristic features associated with OsHV-1 infections were only observed in samples in which the viral DNA was detected by PCR. A previously described competitive PCR method was applied to detect inhibition during PCR reactions. The results show that the method can be used on small amounts of Oyster Larvae (3 mg) for the detection of OsHV-1 DNA by PCR.
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detection of ostreid herpesvirus 1 oshv 1 dna in seawater by pcr influence of water parameters in bioassays
2004Co-Authors: Vassilia Vigneron, Helene Montanie, Gaelle Solliec, Tristan RenaultAbstract:Since 1991, herpesvirus infections have been reported among Larvae and juveniles of various bivalves. Most of the studies focused on detection of viral infections of economically impor- tant species. However, the persistence of bivalve herpesviruses in the marine environment is poorly documented. The present study concerns the role of seawater parameters in Ostreid Herpesvirus 1 (OsHV-1) detection by polymerase chain reaction (PCR). Viral DNA extracted from purified particles or virions present in infected Oyster Larvae were detected by PCR after storage in different media at different temperatures. The lowest detection threshold was found using distilled water or Tris EDTA buffer. In seawater, the threshold was higher. The use of sterile media permitted detection of viral DNA stored over a longer period. Storage temperature also had a significant influence on detection, with lower temperatures promoting DNA detection over a longer period. In summary, water para- meters such as temperature influenced detection of OsHV-1 DNA by PCR. However, the PCR tech- nique may also be successfully applied to samples in natural seawater. Indeed, the PCR technique permitted detection of naked viral DNA at 100 ng l -1 in seawater in bioassays.
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monoclonal antibodies to european flat Oyster ostrea edulis hemocytes characterization and tissue distribution of granulocytes in adult and developing animals
2001Co-Authors: Q Xue, Tristan RenaultAbstract:Monoclonal antibodies specific for hemocyte sub-populations of the European flat Oyster, Ostrea edulis, were prepared using separated granulocytes and hyalinocytes as antigen sources. Six monoclonal antibodies specific for hemocytes were selected. Five of them showed a specificity for more than one hemocyte type and one hybridoma produced a monoclonal antibody reacting specifically with granulocytes. At the ultrastructural level, this monoclonal antibody demonstrated epitopes principally in dense cytoplasmic granules of granulocytes. Western blotting analysis indicated that a peptide of 50kDa was recognized by this antibody. It was therefore used to investigate granulocyte distribution and ontogenesis in European flat Oysters using immunohistochemistry. Granulocytes were mostly observed in connective tissues in different organs. Their distribution pattern in digestive gland, mantle, gills and gonad may indicate different functional status. Moreover, the absence of granulocytes in early larval stages can partly correspond to an immature immune system in Oyster Larvae.
René Robert - One of the best experts on this subject based on the ideXlab platform.
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Interactions between Crassostrea virginica Larvae and Deepwater Horizon oil: Toxic effects via dietary exposure.
2018Co-Authors: Julien Vignier, Anne Rolton, Philippe Soudant, René Robert, Aswani K. VoletyAbstract:Abstract The Deepwater Horizon (DWH) disaster released crude oil in the Gulf of Mexico for 87 days, overlapping with the reproductive season and recruitment of the Oyster Crassostrea virginica. The pelagic larval life stages of C. virginica are particularly vulnerable to contaminants such as polycyclic aromatic hydrocarbons (PAHs) and oil droplets. Based on their lipophilic properties, PAHs and oil droplets can adsorb onto phytoplankton and filter-feeding C. virginica Larvae may be exposed to these contaminants bound to suspended sediment, adsorbed onto algal and other particles, or in solution. This study examined the effects of exposure of C. virginica Larvae to algae mixed with DWH oil. In a 14-day laboratory exposure, 5 day-old C. virginica Larvae were exposed to Tisochrysis lutea mixed with four concentrations of unfiltered DWH oil (HEWAF) in a static renewal system. Larval growth, feeding capacity, abnormality and mortality were monitored throughout the exposure. Total PAH (n = 50) content of the water medium, in which Larvae were grown, were quantified by GC/MS-SIM. Oil droplets were observed bound to algae, resulting in particles in the size-range of food ingested by Oyster Larvae (1–30 μm). After 14 days of exposure, larval growth and survival were negatively affected at concentrations of tPAH50 as low as 1.6 μg L−1. GC/MS-SIM analysis of the exposure medium confirmed that certain PAHs were also adsorbed by T. lutea and taken up by Oyster Larvae via ingestion of oil droplets and/or contaminated algae. Long-term exposure to chronic levels of PAH (1.6–78 μg tPAH50 L−1) was shown to negatively affect larval survival. This study demonstrates that dietary exposure of Oyster Larvae to DWH oil is a realistic route of crude oil toxicity and may have serious implications on the planktonic community and the food chain.
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a dynamic energy budget deb growth model for pacific Oyster Larvae crassostrea gigas
2010Co-Authors: Benjamin Ricovilla, René Robert, Ismael Bernard, Stephane PouvreauAbstract:Abstract Dynamic Energy Budget (DEB) theory aims to quantify the energetic framework of an individual organism as a dynamic model, from the uptake of food to its utilisation in metabolic processes (maintenance, growth, development and reproduction). The purpose of the present paper is to extend the existing DEB model for adult Pacific Oyster Crassostrea gigas to the larval life stage of this species. We present the application of generic DEB theory to Oyster Larvae, with the formulation of the specific assumptions based on the characteristics of this stage. The model depends on seawater temperature and food density, as forcing variables, followed throughout the whole larval development. We calculated DEB parameter values for Larvae by means of laboratory experiments specifically designed to collect datasets on ingestion and growth at different levels of phytoplankton density and temperature. The DEB model developed here showed good growth simulations and provided an extensive description of the energetic needs of C. gigas during its larval stage. It was demonstrated that, at 27 °C, a food density of 1400 µm 3 µl − 1 must be maintained throughout larval development to maximise growth and metamorphosis success. Timing of metamorphosis decreases exponentially with increasing temperature.
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influence of food density and temperature on ingestion growth and settlement of pacific Oyster Larvae crassostrea gigas
2009Co-Authors: Benjamin Ricovilla, Stephane Pouvreau, René RobertAbstract:Abstract Ingestion, growth and metamorphosis of Pacific Oyster, Crassostrea gigas, Larvae were studied under controlled conditions of food density and temperature using a combination of a flow-through rearing system and a hydrobiological monitoring device. In a first experiment Larvae were exposed to three different phytoplankton densities (12, 20 and 40 cells µl− 1) while in a second trial Larvae were reared at five different temperatures (17, 22, 25, 27 and 32 °C). Both food concentration and temperature significantly affected the larval physiology throughout the entire development from D-veliger to young spat. Larvae survived over a wide range of both environmental parameters with high survival at the end of experiments. The feeding functional response provided the maximal ingestion rate (50 000 cells larva− 1 day− 1) which occurred at an algal density of 20 cells µl− 1 surrounding the Larvae and 25 °C. At the highest temperature (32 °C), maximal growth and metamorphosis performances were reached in less than 2 weeks while the lowest temperature (17 °C) consistently inhibited ingestion and growth over the entire larval period. The estimate of the Arrhenius temperature (TA) was 11 000 K for C. gigas Larvae. Larval development could be divided on the basis of feeding activity into an initial mixotrophic period with a lower and constant ingestion over the first days (from D-stage to early umbonate larva of ≈ 110 µm length) followed by an exotrophic phase characterized by a sharp increase in ingestion (umbonate to eyed of ≈ 300 µm length) and, finally, a third period for Larvae ≥ 300 µm during which ingestion decreased suddenly because of metamorphosis. Optimum larval development and settlement of the Oyster C. gigas occurred at 27 °C and an increasing food supply as the Larvae were growing. A food density of ≥ 20 cells µl− 1 of T-ISO + CP or CG (1:1 cells number) in the culture water was required to maximise growth and metamorphosis success.
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competition for food in the Larvae of two marine molluscs crepidula fornicata and crassostrea gigas
2008Co-Authors: Michel Blanchard, Jan A Pechenik, Emilie Giudicelli, Jeanpaul Connan, René RobertAbstract:The degree to which Larvae of the invasive American slipper limpet (Crepidula fornicata) and the Japanese Oyster (Crassostrea gigas) may compete for food was examined during 2003 in the laboratory. Larval microalgae up- take, growth and mortality were compared for Larvae fed each of six species of unicellular algae, ranging in length from 2t o 10μm. Tested diets included the two flagellates Tetraselmis chui (Prasinophyceae) and Isochrysis affinis galbana (T-ISO, Haptophyceae), one member of the Chlorophyceae (Nannochloris atomus), and three diatom species (Chaeto- ceros calcitrans forma pumilum, Chaetoceros gracilis, Skeletonema marinoi). We found that the limpet Larvae ingested phytoplankton over a wider range of cell sizes and ate at higher rates on each diet than did the Oyster Larvae. For exam- ple, Oyster Larvae consumed 2216 cells h −1 of N. atomus, while limpet Larvae consumed the same phytoplankton cells at approximately twice that rate, 5159 cells h −1 , on the same diet. Larvae of both species grew more quickly on a mixture of flagellates than on any of the diatom alone (12 versus 7 μ md −1 for Oyster Larvae and 41 versus 28 μ md −1 for limpet Larvae). Our results suggest that in the Bay of Mount Saint-Michel (France, Western Channel), where Larvae of both species co-exist in the summer, intensive grazing by limpet Larvae can potentially deplete phytoplankton concentrations to cause competition with Oyster Larvae, particularly for smaller sized phytoplankton species.
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new microalgae for the pacific Oyster crassostrea gigas Larvae
2006Co-Authors: Ian Probert, E Ponis, Benoit Veron, Michel Mathieu, René RobertAbstract:Abstract The number of microalgae of high nutritional value actually available to mollusc hatcheries is limited to a few species and this represents a constraint for the industry. Fifteen microalgal species belonging to seven different taxonomic classes were selected from the Algobank-Caen microalgal culture collection of the University of Caen. An initial screening of these microalgae, based on their cytomorphological characteristics and growth performances, led to the selection of four species (Imantonia rotunda, Emiliania huxleyi, Pseudoisochrysis paradoxa and Diacronema vlkianum), which were then tested as food for Crassostrea gigas Larvae. Two species (I. rotunda and E. huxleyi) were of poor food value for Oyster Larvae, while P. paradoxa and D. vlkianum resulted in high growth rate and low mortality. These two microalgae were then characterised (dry weight, ash, gross composition, fatty acids) at different stages of growth and their productivity in standard hatchery conditions (2-l glass carboys, 300-l cylinders) was assessed in order to evaluate the potential of these species for use in commercial hatcheries.
Jeanlouis Nicolas - One of the best experts on this subject based on the ideXlab platform.
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Integrative study of physiological changes associated with bacterial infection in pacific Oyster Larvae.
2013Co-Authors: Bertrand Genard, Jeanlouis Nicolas, Pierre Boudry, Philippe Miner, Dario Moraga, Fabrice Pernet, Réjean TremblayAbstract:BACKGROUND: Bacterial infections are common in bivalve Larvae and can lead to significant mortality, notably in hatcheries. Numerous studies have identified the pathogenic bacteria involved in such mortalities, but physiological changes associated with pathogen exposure at larval stage are still poorly understood. In the present study, we used an integrative approach including physiological, enzymatic, biochemical, and molecular analyses to investigate changes in energy metabolism, lipid remodelling, cellular stress, and immune status of Crassostrea gigas Larvae subjected to experimental infection with the pathogenic bacteria Vibrio coralliilyticus. FINDINGS: Our results showed that V. coralliilyticus exposure induced (1) limited but significant increase of Larvae mortality compared with controls, (2) declined feeding activity, which resulted in energy status changes (i.e. reserve consumption, β-oxidation, decline of metabolic rate), (3) fatty acid remodeling of polar lipids (changes in phosphatidylinositol and lysophosphatidylcholine composition', non-methylene-interrupted fatty acids accumulation, lower content of major C20 polyunsaturated fatty acids as well as activation of desaturases, phospholipase and lipoxygenase), (4) activation of antioxidant defenses (catalase, superoxide dismutase, peroxiredoxin) and cytoprotective processes (heat shock protein 70, pernin), and (5) activation of the immune response (non-self recognition, NF-κκ signaling pathway, haematopoiesis, eiconosoids and lysophosphatidyl acid synthesis, inhibitor of metalloproteinase and antimicrobial peptides). CONCLUSION: Overall, our results allowed us to propose an integrative view of changes induced by a bacterial infection in Pacific Oyster Larvae, opening new perspectives on the response of marine bivalve Larvae to infections.
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protective effect of four potential probiotics against pathogen challenge of the Larvae of three bivalves pacific Oyster crassostrea gigas flat Oyster ostrea edulis and scallop pecten maximus
2012Co-Authors: Aditya Kesarcodiwatson, Philippe Miner, Jeanlouis NicolasAbstract:Abstract Mollusc aquaculture is an important commodity for France with Pacific Oysters, flat Oysters and the great scallop being the three main species. Pacific Oyster Larvae production is currently successful, however larval production of flat Oyster and scallops regularly face problems remedied by antibiotics. Using a bioassay technique, four potential probiotic strains ( Alteromonas macleodii 0444, Neptunomonas sp. 0536, Phaeobacter gallaeciensis , Pseudoaltermonas sp. D41) were tested upon the Larvae of the three mollusc species when challenged with pathogens. Pacific Oysters and flat Oysters were challenged individually with the pathogens Vibrio coralliilyticus and V. pectenicida , while scallops were challenged with V. coralliilyticus and V. splendidus . Survival of the Larvae was measured in challenged Larvae given the probiotics and those without probiotic. In scallop Larvae, protection against V. coralliilyticus and V. splendidus was provided by prior administration of P. gallaeciensis (29% and 53% better than the respective pathogen controls), A. macleodii 0444 (30%, 36%) and Neptunomonas sp. 0536 (36%, 55%). Significant protection with Pseudoalteromonas sp. D41 was only provided against V. splendidus (35%). In flat Oyster Larvae, protection against V. coralliilyticus and V. pectenicida was provided by P. gallaeciensis . (73%, 69%) and A. macleodii 0444 (45%, 53%). Neptunomonas sp. 0536 provided significant protection only against V. pectenicida (48% higher). Use of Pseudoalteromonas sp. D41 did not offer significant protection for flat Oyster Larvae against either pathogen. Experiments with Pacific Oysters suggested that Pseudoalteromonas sp. D41 and P. gallaeciensis could be effective against challenge by V. coralliilyticus (50% and 40% improved survival respectively) but not against V. pectenicida . The results indicate that P. gallaeciensis , A. macleodii 0444, Neptunomonas sp. 0536 and Pseudoalteromonas sp. D41 could be useful in mollusc larviculture.
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bacterial problems associated with scallop pecten maximus larval culture
1996Co-Authors: Jeanlouis Nicolas, René Robert, Sophie Corre, Gilles Gauthier, Dominique AnsquerAbstract:Scallop Pecten maximus Larvae have been cultured at the Argenton and Tinduff (Brittany, France) hatcheries with antibiotic treatment (chloramphenicol at 8 ppm) for 15 yr. Without treatment, outbreak of disease has normally occurred between Day 12 and Day 19 or sometimes earlier. A bacteriological study of Larvae reared with and without antibiotic was performed over a 4 yr period. Among the collected strains, 2 clusters (C and F) of vibrios were present at high densities only in Larvae cultured without treatment. One cluster (C) was routinely isolated over the 4 yr of study, while the other (F) was collected only in the third year. Their virulence with respect to scallop Larvae and their lack of infectivity with respect to Oyster Larvae were demonstrated in an exposure experiment. The vibrio F strain tended to lose its virulence after 5 subcultures, whereas the vibrio C strain retained the ability to kill scallop Larvae in experimental infections. Three other vibrios isolated in moribund Oyster Larvae caused mortality in Oyster Larvae but not in scallop Larvae. Different methods were used to determine the taxonomic position of these virulent bacteria. The phenotypic traits of bacterial isolates were determined with the Biolog GN microplate, the API 20E system and the reference method. Patterns of cytoplasmic proteins were identified by electrophoresis in SDS-PAGE. These different methods consistently confirmed the existence of 2 vibrio species pathogenic to scallop Larvae. Affiliation of cluster F with Vibrio splendidus was assessed by Biolog tests and by analysis of 16S rRNA sequences. One pathogenic bacteria of Oyster Larvae was also very close to this second cluster, whereas the 2 others from moribund Oyster Larvae and cluster C may constitute 2 different species.
Linsheng Song - One of the best experts on this subject based on the ideXlab platform.
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ocean acidification inhibits initial shell formation of Oyster Larvae by suppressing the biosynthesis of serotonin and dopamine
2020Co-Authors: Zhaoqun Liu, Zhi Zhou, Yukun Zhang, Lingling Wang, Xiaorui Song, Weilin Wang, Yan Zheng, Yanan Zong, Linsheng SongAbstract:Abstract Ocean acidification has severely affected the initial shell formation of marine bivalves during their larval stages. In the present study, it was found that dopamine (DA) content in early D-shape Larvae was significantly higher than that in trochophore and D-shape Larvae, while the serotonin (5-HT) content in early D-shape Larvae and D-shape Larvae was obviously higher than that in trochophore. Incubation of trochophore with 5-HT or DA could accelerate the formation of calcified shell, and the treatments with selective antagonists of receptors for 5-HT and DA (Cg5-HTR-1 and CgD1DR-1) obviously inhibited the formation of calcified shells. When Oyster Larvae were subjected to an experimental acidified treatment (pH 7.4), the biosynthesis of 5-HT and DA was inhibited, while the mRNA expression levels of the components in TGF-β pathway were significantly up-regulated in D-shape Larvae. Moreover, the phosphorylation of TIR and the translocation of smad4 were hindered upon acidification treatments, and the expression patterns of chitinase and tyrosinase were completely reverted. These results collectively suggested that monoamine neurotransmitters 5-HT and DA could modulate the initial shell formation in Oyster Larvae through TGF-β smad pathway by regulating the expression of tyrosinase and chitinase to guarantee the chitin synthesis for shell formation. CO2-induced seawater acidification could suppress the biosynthesis of 5-HT and DA, as well as the activation of TGF-β smad pathway, which would subvert the expression patterns of chitinase and tyrosinase and cause the failure of initial shell formation in Oyster early D-shape Larvae.
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metabolomic and transcriptomic profiling reveals the alteration of energy metabolism in Oyster Larvae during initial shell formation and under experimental ocean acidification
2020Co-Authors: Zhaoqun Liu, Zhi Zhou, Yukun Zhang, Lingling Wang, Yan Zheng, Yanan Zong, Chang Liu, Ning Kong, Qiang Gao, Linsheng SongAbstract:Marine bivalves secrete calcified shells to protect their soft bodies from predation and damages, which is of great importance for their survival, and for the safety of the coastal ecosystem. In recent years, larval shell formation of marine bivalves has been severely affected by ocean acidification (OA), and previous study indicated that OA might affect such process by disrupting endogenous energy metabolism. Developmental stages from trochophore to D-shape Larvae are extremely important for initial shell formation in Oyster since a calcified shell was formed to cover the chitin one. In the present study, metabolomic and transcriptomic approaches were employed to investigate the energy metabolism of Oyster Larvae during initial shell (prodissoconch I, PDI shell) formation and under experimental OA treatment. Totally 230 chemical compounds were identified from the present dataset, most of which were highly expressed in the "middle" stage (early D-shape Larvae) which was critical for PDI shell formation since a calcified shell was formed to cover the chitin one. Several compounds such as glucose, glutarylcarnitine (C5), β-hydroxyisovaleroylcarnitine, 5-methylthioadenosine (MTA), myristoleate (14:1n5) and palmitoleate (16:1n7) were identified, which were involved in energy metabolic processes including amino acid oxidation, glycolysis, pentose phosphate pathway and fatty acid metabolism. In addition, mRNA expressions of genes related to protein metabolism, glycolysis, lipid degradation, calcium transport and organic matrix formation activities were significantly down-regulated upon experimental OA. These results collectively suggested that formation of the initial shell in Oyster Larvae required endogenous energy coming from amino acid oxidation, glycolysis, pentose phosphate pathway and fatty acid metabolism. These metabolic activities could be severely inhibited by experimental OA, which might alter the allocation of endogenous energy. Insufficient endogenous energy supply then suppressed the mobilization of calcium and resulted in a failure or delay in PDI shell formation.
Luc A Comeau - One of the best experts on this subject based on the ideXlab platform.
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sink before you settle settlement behaviour of eastern Oyster crassostrea virginica Larvae on artificial spat collectors and natural substrate
2019Co-Authors: Luke A Poirier, Jeff C Clements, J Davidson, Gilles Miron, Luc A ComeauAbstract:Abstract Eastern Oysters (Crassostrea virginica) are ecosystem engineers that are important to the ecological and economic sustainability of Atlantic Canada’s estuarine resources. Recently, there has been an increased industry demand for Oyster spat (i.e., newly-settled Larvae), which is often collected using artificial spat collectors suspended in the water column. Little is known, however, about the interactions between artificial spat collectors and naturally occurring substrates, and whether or not such collectors can affect Oyster recruitment to wild beds which are simultaneously fished. In the laboratory, we mimicked the typical set-up of artificial spat collectors used in Atlantic Canada to measure differences in spat recruitment between locally-used artificial collectors and natural shell substrate under real-life spat-collection scenarios. Larvae were allowed to settle on various substrates where they occur in a natural system and were subsequently counted. In both single substrate and choice experiments, results indicated that Oyster Larvae recruited in higher numbers to natural shell substrate located on the benthic surface compared to suspended shell; and there were no significant differences among suspended substrates. This experiment provides evidence supporting existing theories around recruitment behaviour by Oyster Larvae, mainly that settling Oysters tend to sink before they settle, suggesting that spat collectors in the wild may have little effect on wild recruitment. With increasing densities of artificial collectors in estuarine systems to meet system demands, however, further research is needed to investigate the potential draw of Oyster Larvae away from benthic Oyster beds under more realistic natural conditions before broad conclusions regarding spat collector effects on wild Oyster populations can be achieved.
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Sink before you settle: Settlement behaviour of Eastern Oyster (Crassostrea virginica) Larvae on artificial spat collectors and natural substrate
2019Co-Authors: Luke A Poirier, Jeff C Clements, J Davidson, Gilles Miron, John D.p. Davidson, Luc A ComeauAbstract:Eastern Oysters (Crassostrea virginica) are ecosystem engineers that are important to the ecological and economic sustainability of Atlantic Canada’s estuarine resources. Recently, there has been an increased industry demand for Oyster spat (i.e., newly-settled Larvae), which is often collected using artificial spat collectors suspended in the water column. Little is known, however, about the interactions between artificial spat collectors and naturally occurring substrates, and whether or not such collectors can affect Oyster recruitment to wild beds which are simultaneously fished. In the laboratory, we mimicked the typical set-up of artificial spat collectors used in Atlantic Canada to measure differences in spat recruitment between locally-used artificial collectors and natural shell substrate under real-life spat-collection scenarios. Larvae were allowed to settle on various substrates where they occur in a natural system and were subsequently counted. In both single substrate and choice experiments, results indicated that Oyster Larvae recruited in higher numbers to natural shell substrate located on the benthic surface compared to suspended shell; and there were no significant differences among suspended substrates. This experiment provides evidence supporting existing theories around recruitment behaviour by Oyster Larvae, mainly that settling Oysters tend to sink before they settle, suggesting that spat collectors in the wild may have little effect on wild recruitment. With increasing densities of artificial collectors in estuarine systems to meet system demands, however, further research is needed to investigate the potential draw of Oyster Larvae away from benthic Oyster beds under more realistic natural conditions before broad conclusions regarding spat collector effects on wild Oyster populations can be achieved. Keywords: Aquaculture-environment interactions, Invertebrate settlement, Larval behaviour, Population recruitment, Shellfish aquacultur
