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Dutertre, Mickael; Grall, Jacques; Ehrhold, Axel; Hamon, Dominique. |
This study used a large spatial scale approach in order to better quantify the relationships between maerl bed structure and a selection of potentially forcing physical factors. Data on maerl bed structure and morpho-sedimentary characteristics were obtained from recent oceanographic surveys using underwater video recording and grab sampling. Considering the difficulties in carrying out real-time monitoring of highly variable hydrodynamic and physicochemical factors, these were generated by three-dimensional numerical models with high spatial and temporal resolution. The BIOENV procedure indicated that variation in the percentage cover of thalli can best be explained (correlation = 0.76) by a combination of annual mean salinity, annual mean nitrate... |
Tipo: Text |
Palavras-chave: Benthic habitats; Brittany; Environmental factors; Estuary; Large spatial scale; Maerl. |
Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00280/39089/37816.pdf |
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Barille, Laurent; Lerouxel, Astrid; Dutertre, Mickael; Haure, Joel; Barille, Anne-laure; Pouvreau, Stephane; Alunno-bruscia, Marianne. |
We compared growth simulations by dynamic energy budget (DEB) and scope for growth (SFG) models of the Pacific oyster Crassostrea gigas, cultivated in Bourgneuf Bay on the French Atlantic coast. This bay is located at a latitude in the middle of the European range of the species, and is characterized by high concentrations of suspended particulate matter (SPM) and a marked gradient between high-turbidity sites in the north (daily SPM > 500 mg L-1) and intermediate-turbidity sites in the south. The models use two forcing variables: seawater temperature and food density. We tested two indices of food availability: chlorophyll a and microalgal concentrations. In the SFG model, food intake is simulated by a type-II Holling functional response, as in the DEB... |
Tipo: Text |
Palavras-chave: Oyster; Dynamic Energy Budget model; Scope for growth model; Turbidity. |
Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00043/15433/12783.pdf |
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Dutertre, Mickael; Beninger, Peter G.; Barille, Laurent; Papin, Mathias; Haure, Joel. |
The recent appearance and invasion of feral oysters (Crassostrea gigas) along the northern European Atlantic coast, underscores the necessity to investigate the relationship between environmental variables, reproductive physiology, larval development and recruitment. We studied these relationships at both high (HT) and intermediate (IT) - turbidity sites, through historical data on water temperatures, multi-parameter environmental probes, histological analyses, and field collections of planktonic larvae and settled post-larvae in 2005 and 2006. A progressive warming trend was observed, especially since 1995, when oyster proliferation first became severe. Threshold temperatures for oocyte growth, larval development and settlement were achieved in both 2005... |
Tipo: Text |
Palavras-chave: Aquaculture; Climate warming; Coastal waters; Crassostrea gigas; Reproductive cycle; Oyster larvae; Settlement; Turbidity. |
Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00000/11150/7938.pdf |
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Dutertre, Mickael; Ernande, Bruno; Haure, Joel; Barille, Laurent. |
Spatial and temporal variations in gill and palp size were studied during 1 year in naturally-settled populations of the Pacific oyster Crassostrea gigas, reciprocally transplanted between two contrasting sites located along a marked gradient of turbidity conditions. The variability of suspended particulate matter (SPM) and food particles, estimated by the concentration of chlorophyll-a, was measured with in situ water-quality probes. Over a full seasonal cycle, oysters exposed to high-turbidity (HT) conditions exhibited a lower gill-to-palp (G:P) ratio, compared with those exposed to low-turbidity (LT) conditions. Seasonal variations in the G:P ratio were observed at the LT site in relation to the spring phytoplanktonic bloom, but differed from those that... |
Tipo: Text |
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Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00351/46223/46145.pdf |
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Dutertre, Mickael; Beninger, Peter G.; Barille, Laurent; Papin, Mathias; Rosa, Philippe; Barille, Anne-laure; Haure, Joel. |
The proliferation of the voluntarily-introduced cupped oyster, Crassostrea gigas, has attained the proportions of species invasion in many intertidal habitats in Europe, presumably resulting from successful reproduction of farmed individuals. It is thus imperative to better understand the reproductive characteristics of farmed oysters, since they are directly under human control. We quantified the dry tissue mass (DTM), gametosomatic index (GSI), and reproductive cycle of farmed oysters at two sites in Bourgneuf Bay, France, in relation to environmental parameters using continuously-recording probes in 2005 and 2006. The GSI was developed for this study, based on the actual area occupied by gametes, rather than the area of the gonad previously used for... |
Tipo: Text |
Palavras-chave: Atlantic Ocean; Crassostrea gigas; Oyster farming; Bivalve; Gametosomatic index; Biological invasion; Atresia; Oocytes; Turbidity; Temperature; Reproduction. |
Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6871.pdf |
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