Éditeur(s) : Elsevier
Résumé : Introduction of non-indigenous species can alter marine communities and ecosystems. In shellfish farming, transfer of livestock, especially oysters, is a common practice and potentially constitutes a pathway for non-indigenous introductions. Many species of seaweeds are believed to have been accidentally introduced in association with these transfers, but there is little direct evidence. We experimentally simulated the transfer of oysters from the Thau Lagoon (France). These transfers involved increasing periods of aerial emersion and additional brine and hot water treatments. The brine and hot water treatments were evaluated as a means of reducing the probability of algal introductions with oyster transfers. Shells were cultured for 40 days in experimental tanks to identify the macroalgae likely to be introduced with any oyster transfer. A total of 57 macroalgal taxa, including 16 taxa not indigenous to the Thau Lagoon, were recorded across all treatments and experiments. The abundance of some species increased in several cases following aerial emersion. Elimination treatments (immersion in brine or hot water) significantly reduced algal diversity, with hot water treatments resulting in no species or only tubular Ulva spp. present. The results support the hypothesis that oyster transfers are effective as primary and secondary vectors of macroalgal introductions. Relatively simple changes to the transfer practice (particularly hot water treatments) are suggested as a means of reducing the risk of non-indigenous algal introductions.
Biological Conservation (0006-3207) (Elsevier), 2007-06 , Vol. 137 , N. 2 , P. 237-247

Droits : 2007 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/2007/publication-2779.pdf
DOI:10.1016/j.biocon.2007.02.001
http://archimer.ifremer.fr/doc/00000/2779/

Éditeur(s) : Université d'Angers
Résumé : In oyster farming areas, organic matter fluxes toward sediment is increased. Pacific oysters (Crassostrea gigas) reject organic-rich faeces and pseudofaeces as a result of filtration process. Organic matter can be consumed by benthic fauna, but in excess it can entails the reduction of benthic faunal species richness, abundance and biomass. Organic matter degradation also induces hypoxic (or anoxic) conditions in the sediment, and production of ammonia and sulfides in toxic concentrations. The main objective of this study is to assess the effects of oyster farming on benthic intertidal ecosystems in the Pertuis Charentais. Benthic macrofauna, living (stained) foraminifera, and physicochemical characteristics of the water column and sediment were used as indicators to evaluate these effects. A multidisciplinary approach was conducted across the Pertuis Charentais at 3 different spatial scales: an oyster trestle (micro-scale), an oyster culture area (meso-scale) and various sites across the Pertuis Charentais (macro-scale). The study was also realised at 4 different temporal scales: some months for the spatial micro-scale, every two weeks for 2 years at meso-scale and once per season during one year at macro-scale. In this study, I found that oyster farming enriches sediment in fine particles, organic matter (up to 12 %), particulate organic carbon (15-20 µg mg 1) and leads to high microphytobenthic biomass. Moreover, the association of seasonnal warming (during spring and summer), remineralisation of accumulated organic matter and short-term hypoxic conditions leads to sulfides and ammonium production. Consequently, the benthic biodiversity decreases and the population dynamic is disturbed. The population dynamic disturbance is characterised by fast abundance rises followed by high mortality rates. In these conditions, tolerant benthic macrofaunal (Cirratulidae, Spionidae and Capitellidae) and foraminiferal (Ammonia tepida and Cribroelphidium gunteri) species are promoted. AMBI index confirms "medium" ecological quality of oyster farming areas. On the contrary, across the control sites, sensible species are maintained (Amphipods, Rosalina cf. vilardeboana). Comparison of oyster farming techniques shows that on-bottom culture is less disturbing for benthic ecosystem than off-bottom culture. Axial tomodensitometry, an innovative method, was used to describe in 3D the sedimentary column organisation. I show that oyster farming modifies the sedimentary column functioning. Indeed, the macrofaunal diversity decrease leads to the modification of the functional diversity of assemblages. Thus, the vertical distribution of living foraminifera is limited in oyster farming areas, because their distribution is tightly related to macrofaunal bioturbating modes.
Dans les zones ostréicoles, les flux de matière organique sont importants, l'huître Crasssotrea gigas rejetant sous forme de pseudo-fécès et de fécès de grandes quantités de matière organique. De ce fait, bien que cette matière organique puisse être consommée par la faune benthique, sa surabondance peut provoquer une réduction de la richesse spécifique, de l'abondance et de la biomasse et provoquer sur le plan des processus biogéochimiques des déplétions en oxygène et l'apparition de substances comme l'ammonium et les sulfures dont les concentrations peuvent devenir toxiques. L'objectif principal de cette étude était donc de déterminer l'impact de l'ostréiculture, grâce à plusieurs indicateurs, sur le compartiment benthique d'un écosystème littoral comme les pertuis charentais. Pour évaluer ces effets, la macrofaune benthique et les foraminifères vivants benthiques ont été utilisés en association avec des mesures des paramètres physico-chimiques de la colonne d'eau et du sédiment. Une approche pluridisciplinaire a ainsi été menée dans les pertuis charentais à trois échelles spatiales différentes : à l'échelle d'une table ostréicole (micro-échelle), à l'échelle d'un site ostréicole (méso-échelle) et à l'échelle des pertuis charentais (macro-échelle). Dans les trois cas, un suivi dans le temps a été associé à une étude de distribution spatiale, quelques mois à micro-échelle, tous les quinze jours pendant deux années à méso-échelle et une fois par saison pendant une année à macro-échelle. Ces différentes approches ont permis d'avoir une vision pertinente de la dynamique et de la réponse fonctionnelle de la faune benthique aux changements induits par la présence de l'ostréiculture. La présence des cultures ostréicoles dans les pertuis charentais enrichit les sédiments en particules fines, en matière organique (12 %), en carbone organique particulaire (15-20 µg mg-1) et favorise une production microphytobenthique élevée. Pendant la période chaude de l'année printemps-été, la reminéralisation de la matière organique accumulée associée à des hypoxies temporaires a favorisé la production de sulfures et d'ammonium. Dans les stations soumises à l'ostréiculture, la diversité des assemblages diminue. La dynamique des espèces est caractérisée par des augmentations rapides des abondances suivies d'épisodes de mortalité. Les espèces tolérantes de la macrofaune benthique (Cirratulidae, Spionidae et Capitellidae) et des foraminifères vivants benthiques (Ammonia tepida et Cribroelphidium gunteri) sont favorisées. Le calcul de l'indice AMBI confirme la qualité écologique moyenne de ces sites. Au contraire, dans la station témoin, les espèces sensibles sont favorisées (Amphipodes, Rosalina cf. vilardeboana). La comparaison de la technique de culture sur table et de culture à plat a montré que la culture des huîtres à plat est moins perturbante pour le milieu. L'étude de la bioturbation a montré l'influence qui existe entre le mode de bioturbation des différents groupes de la macrofaune et la répartition verticale des foraminifères vivants dans la colonne sédimentaire. La diminution de la diversité des assemblages de la macrofaune dans les zones soumises à l'ostréiculture modifient la diversité fonctionnelle de ces assemblages et affectent le fonctionnement de la colonne sédimentaire, limitant la répartition verticale des foraminifères dans ces zones.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2007/these-2582.pdf
http://archimer.ifremer.fr/doc/00000/2582/

Éditeur(s) : Elsevier Science Bv
Résumé : In bivalve aquaculture, dominant fouling organisms are filter feeders which can compete for food with reared bivalves, sometimes causing mortality or reducing their growth rate. This study investigated the effect of biofouling on the farmed pearl oyster Pinctada margaritifera in two lagoons of French Polynesia. Survival, growth and reproduction of 2 year-old pearl oysters were monitored with regular sampling schedules, from the initial stage of colonization up to 20 months of biofouling accumulation. Control groups of pearl oysters were kept free of biofouling as is the current practice in pearl farms. After more than a year of monitoring, no significant difference was recorded in shell growth rate between pearl oysters reared with epibionts and the control group of pearl oysters, at both sites. Mean annual shell growth rate (height) was 30.5 ± 9.2 mm in Tahiti and 24.8 ± 7.7 mm in Mangareva. Neither the survival nor the reproduction indices were negatively affected by biofouling. In Mangareva, where biofouling development was quantified during 1 year, the rate of colonization appeared to be high during the first 3 months before slowing down. These results raise questions about the necessity of removing biofouling at this stage of pearl oyster production (i.e. before grafting).
Aquaculture (0044-8486) (Elsevier Science Bv), 2014-10 , Vol. 434 , P. 18-26

Droits : 2014 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00201/31188/29587.pdf
DOI:10.1016/j.aquaculture.2014.07.012
http://archimer.ifremer.fr/doc/00201/31188/

Éditeur(s) : Elsevier
Résumé : We investigated the influence of bioturbation by macrofauna on the vertical distribution of living (stained) benthic foraminifera in marine intertidal sediments. We investigated the links between macrofaunal bioturbation and foraminiferal distribution, by sampling from stations situated on a gradient of perturbation by oyster-farming, which has a major effect on benthic faunal assemblages. Sediment cores were collected on the French Atlantic coast, from three intertidal stations: an oyster farm, an area without oysters but affected by oyster biodeposits, and a control station. Axial tomodensitometry (CT-scan) was used for three-dimensional visualization and two-dimensional analysis of the cores. Biogenic structure volumes were quantified and compared between cores. We collected the macrofauna, living foraminifera, shells and gravel from the cores after scanning, to validate image analysis. We did not investigate differences in the biogenic structure volume between cores. However, biogenic structure volume is not necessarily proportional to the extent of bioturbation in a core, given that many biodiffusive activities cannot be detected on CT-scans. Biodiffusors and larger gallery-diffusors were abundant in macrofaunal assemblage at the control station. By contrast, macrofaunal assemblages consisted principally of downward-conveyors at the two stations affected by oyster farming. At the control station, the vertical distribution of biogenic structures mainly built by the biodiffusor Scorbicularia plana and the large gallery-diffusor Hediste diversicolor was significantly correlated with the vertical profiles of living foraminifera in the sediment, whereas vertical distributions of foraminifera and downward-conveyors were not correlated at the station affected by oyster farming. This relationship was probably responsible for the collection of foraminifera in deep sediment layers (> 6 cm below the sediment surface) at the control station. As previously suggested for other species, oxygen diffusion may occur via the burrows built by S. plana and H. diversicolor, potentially increasing oxygen penetration and providing a favorable microhabitat for foraminifera in terms of oxygen levels. By contrast, the absence of living foraminifera below 6 cm at the stations affected by oyster farming was probably associated with a lack of biodiffusor and large gallery-diffusor bioturbation. Our findings suggest that the effect of macrofaunal bioturbation on the vertical distribution of foraminiferal assemblages in sediments depends on the effects of the macrofauna on bioirrigation and sediment oxidation, as deduced by Eh values, rather than on the biogenic structure volume produced by macrofauna. The loss of bioturbator functional diversity due to oyster farming may thus indirectly affect infaunal communities by suppressing favorable microhabitats produced by bioturbation.
Journal of Experimental Marine Biology and Ecology (0022-0981) (Elsevier), 2009-03 , Vol. 371 , N. 1 , P. 20-33

Droits : 2009 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2009/publication-6146.pdf
DOI:10.1016/j.jembe.2008.12.012
http://archimer.ifremer.fr/doc/00000/6146/

Éditeur(s) : Styli 2003. Trente ans de crevetticulture en Nouvelle-Calédonie. Nouméa - Koné, 2-6 juin 2003. 2004. Gorarant C, Harache Y, Herbland A, Mugnier C. Ed. Ifremer, Actes de Colloque, n°38, pp.113-120
Résumé : Two oyster species are currently present along the French coasts : the indigenous European flat oyster (Ostrea edulis), and the Pacific cupped oyster (Crassostrea gigas), that has been introduced from Japan since the beginning of the 70ies. The flat oyster successively suffered from two protozoan diseases during the 60ies and its production decreased from 20 000 tons/year by that time to 1 500 tons/year nowadays. Consequently, the oyster production is principally (99%) based upon the Pacific oyster species with approximately 150 000 tons/year among which 90% are grown from the natural spat. However, the hatchery production of this species is developing and was estimated to 400 to 800 millions spat in 2002. Moreover, strengthened relationships between IFREMER and the 5 commercial hatcheries, that all joined the SYSAAF (Union of the French poultry, shellfish and fish farming selectors), allow to plan for new genetic breeding programs. At the end of the 80ies, IFREMER initiated a genetic breeding program for the resistance of the European flat oyster to the bonamiosis, and obtained strains more tolerant to this disease. After two generations of massal selection, molecular markers had identified a reduced genetic basis in this program. It was then reoriented to an intra-familial selection. However, we were confronted to a zootechnic problem to manage such a scheme and we compromised by an intra-cohorts of families selection scheme managed using molecular markers. The program has now reached the transfer level with experimentation at a professional scale. Concerning the Pacific cupped oyster, and in parallel with the obtaining and the study of polyploids, performance of different Asian cupped oyster strains were compared to the one introduced in France thirty years ago and currently suffering from summer mortalities. The local strain exhibited better performance, certainly based upon a good local adaptation. In other respects, although early growth is a relevant criteria for selection for growth to commercial stage, it is not to be privileged in the context of an oyster producing region with a limited food availability. Contrary, the spat summer mortality became a priority for numerous teams (genetic, physiology, pathology, ecology,...) joined in the MOREST program. The first results showed important survival differences between fullsib and halsib families. They indicate a genetic determinism to this character "survival" and promote for its selection.
Deux espèces d'huîtres sont aujourd'hui présentes sur les côtes françaises : l'huître plate européenne (Ostrea edulis), indigène, et l'huître creuse du Pacifique (Crassostrea gigas), introduite du Japon dans le début des années 1970. L'huître plate a subi coup sur coup, dans les années 1960, deux maladies dues à des protozoaires parasites et sa production est ainsi passée de 20 000 t/an dans les années 1960 à 1500 t/an aujourd'hui en France. Il en résulte que la filière ostréicole française repose quasiment exclusivement (99%) sur la production de l'huître creuse, C. gigas, avec 150 000 tonnes en 2000 dont environ 90% est issu du captage naturel. Cependant, la reproduction de cette espèce en écloserie est actuellement en expansion avec une estimation de 400 à 800 millions de naissains commercialisés en 2002. Des rapports renforcés entre l'IFREMER et les cinq écloseries françaises de la filière ostréicole, qui adhèrent toutes au SYSAAF (SYndicat des Sélectionneurs Avicoles et Aquacoles Français), permettent désormais d'envisager le développement de nouveaux programmes d'amélioration génétique. A la fin des années 1980, un programme de sélection pour la résistance de l'huître plate à la bonamiose a été initié au sein de l'IFREMER, et a permis d'obtenir des souches plus tolérantes à cette maladie. Après deux générations en sélection massale, les marqueurs moléculaires avaient mis en évidence une base génétique réduite au sein de ce programme qui s'était alors orienté vers une sélection intra-familiale. Devant la lourdeur zootechnique d'un tel schéma, un compromis a été trouvé en réalisant une sélection au sein de cohortes de familles biparentales, la gestion de ces cohortes étant permise par les analyses moléculaires. Le programme est maintenant dans sa phase de transfert, avec des expérimentations à plus grande échelle en partenariat avec la profession. En ce qui concerne l'huître creuse, et en parallèle de l'obtention et l'étude de polyploïdes, les performances de différentes souches d'huîtres creuses provenant d'Asie ont été comparées à celles de la souche introduite en France il y a trente ans, sujette à des mortalités estivales. La souche locale présente de meilleures performances, vraisemblablement grâce à une adaptation bien réalisée. Par ailleurs, bien que l'amélioration de la croissance jusqu'à la taille commerciale s'avère possible par une sélection précoce au stade larvaire, le critère de croissance n'est pas nécessairement à privilégier dans le contexte d'un bassin ostréicole disposant de ressources trophiques limitées. En revanche, les importantes mortalités rencontrées par le naissain en périodes estivales constituent le sujet d'étude prioritaire sur lequel se sont penchées de nombreuses équipes (génétique, physiologie, pathologie, écologie, ...) dans le cadre du grand défi MOREST. Les premiers résultats ont mis en évidence de fortes différences de survie entre des familles biparentales d'animaux indiquant un déterminisme génétique du caractère « survie », et encourageant dans la voie d'une sélection pour ce caractère.

Droits : 2004 Ifremer
http://archimer.ifremer.fr/doc/2003/acte-3491.pdf
http://archimer.ifremer.fr/doc/00000/3491/

Éditeur(s) : ISTPM
Résumé : Table of Contents The Natural Environment Production centres Oyster farming centres Mussel farming centres Chapter I. - The Physicochemical Environment I. Sea Water a) Transparency, turbidity b) Temperature c) Salinity d) Dissolved gases e) Substances dissolved in the water f) Water movements g) Hydrology of the main shellfish farming centres II. Soils a) Soil properties b) Mechanical amendment of soils, its effects c) Fertilisation of soils in shellfish farming d) Changes in soils due to farming Bibliography Chapter II. - The Natural Environment Phytoplankton Zooplankton Basic biology of phytoplankton Assessment of phytoplankton production, notion of primary productivity Phytoplankton from a few shellfish farming regions Microphytobenthos Factors controlling primary productivity Toxicity of planktonic organisms; red tides Bibliography Chapter III – Alterations in the Natural Environment Pollution I. Chemical Pollution Definitions Influence of turbidity A. Telluric pollution 1o Domestic pollution 2o Agriculture-related pollution 3o Industrial pollution B. Pelagic pollution 1o Pollution through hydrocarbons Conclusion II. Bacterial Pollution Future of micro-organisms in the sea A. Specimen conditions B. Phenomena of dispersion Survival of germs in the marine environment A. Factors influencing the total microbial content B. Resistance of various groups of germs Consequences of bacterial pollutions on shellfish and shellfish farming Shellfish Shellfish farming Conclusion Bibliography
Sommaire : Le milieu naturel Les centres de production Les centres ostréicoles Les centres mytilicoles Chapitre I. - le milieu physico-chimique I. L'eau de mer a) Transparence, turbidité b) Température c) Salinité d ) Les gaz dissous e) Les substances dissoutes dans l'eau f) Les mouvements de l'eau g) Hydrologie des principaux centres conchylicoles IL Les sols a ) Propriétés des sols b) Amendement mécanique des sols, ses effets c) La fertilisation des sols en conchylicutture d) Evolution des sols du fait de la culture Bibliographie Chapitre II. - le milieu biologique Le phytoplancton Le zooplancton Biologie sommaire du phytoplancton Evaluation de la production de phytoplancton, notion de productivité primaire Phytoplancton de quelques régions conchylicoles Le microphytobenthos Facteurs contrôlant la productivité primaire Toxicité d'organismes planctoniques ; les eaux rouges bibliographie Chapitre III - les altérations du milieu naturel. Les pollutions I. Les pollutions chimiques Définitions Influence de la turbidité A. Pollution tellurique 1° Pollution d'origine domestique 2° Pollutions liées aux activités agricoles 3° Pollutions industrielles B. Pollution pélagique 1° Pollution par les hydrocarbures Conclusion II. Les pollutions bactériennes Devenir des microorganismes dans la mer A. Conditions de prélèvements B. Phénomènes de dispersion Survie des germes dans le milieu marin A. Facteurs influant sur la teneur microbienne globale B. Résistance des divers groupes de germes Conséquences des pollutions bactériennes sur les coquillages et sur la conchyliculture Les coquillages La conchyliculture Conclusion Bibliographie
Revue des Travaux de l'Institut des Pêches Maritimes (0035-2276) (ISTPM), 1974-09 , Vol. 38 , N. 3 , P. 217-337

Droits : Ifremer
http://archimer.ifremer.fr/doc/1974/publication-1776.pdf
http://archimer.ifremer.fr/doc/00000/1776/

Éditeur(s) : Elsevier
Résumé : The ecological quality status (EcoQ) of intertidal mudflats constrained by Pacific oyster farming was assessed by single (H', AMBI, BENTIX and BOPA) and multimetric (M-AMBI and average score) index approaches in the Pertuis Charentais (SW France). Fifteen sampling stations were monitored seasonally for sedimentological features and macrozoobenthos in 2004. Sediments affected by oyster biodeposits showed organic matter enrichment, and sediments from off-bottom culture sites had higher organic matter contents and lower redox potentials than sediments from on-bottom culture sites. Biotic indices consistently registered responses of macrozoobenthos to organic enrichment but there was only partial agreement between single index-derived EcoQs. The average score was better than M-AMBI and single indices for determining EcoQs. Accordingly, oyster farming alters intertidal macrozoobenthic assemblages moderately, and off-bottom cultures cause more disturbance than on-bottom cultures. Hydrodynamics and seasons may interact with culture practices in smothering/strengthening biodeposition-mediated effects through dispersal/accumulation of biodeposits.
Marine Pollution Bulletin (0025-326X) (Elsevier), 2008-11 , Vol. 56 , N. 11 , P. 1898-1912

Droits : 2008 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4650.pdf
DOI:10.1016/j.marpolbul.2008.07.010
http://archimer.ifremer.fr/doc/00000/4650/

Éditeur(s) : Actes du IIIème Congrès International des Sociétés Françaises de Malacologie. Les mollusques dans la recherche actuelle, La Rochelle, France, 24-27 juin 2003
Résumé : We analysed a few aspects of oyster culture in New Caledonia. Oyster culture there is not very important, one farm producing 30 tonnes of Japanese oysters per year and the other one, 3 tonnes of rock oysters. Mangrove oyster deposits are traditionally exploited, and this exploitation lead to a decrease of the densities and biomasses observed in the most exploited estuaries. On the four monitored sites, the maximum size observed is comprised between 7.2 to 10 cm, for a mode comprised between 3.6 and 4.8 cm. Densities go from 31 to 251 oysters and biomasses, from 0.751 to 2.553 kg/m2. Regulations focus on the minimum collection size (6 cm) and a fishing prohibition period of 8 months. Based on our observations, we suggest that these dispositions be maintained. We also suggest that a fishing licence for professional fishermen be created, and that leisure fishing be maintained.
On a analysé quelques aspects de l'exploitation des huîtres en Nouvelle Calédonie. La conchyliculture y est faiblement présente, une ferme produisant 30 tonnes par an d'huîtres japonaises et une autre, 3 tonnes d'huîtres de rocher. Les gisements d'huître de palétuvier font l'objet d'une exploitation traditionnelle, qui a conduit à l'affaiblissement des densités et des biomasses observées dans les estuaires les plus exploités. Dans les quatre sites échantillonnés, la taille maximale observée allait de 7,2 à 10 cm, pour un mode compris entre 3,6 et 4,8 cm. Les densités allaient de 31 à 251 huîtres et les biomasses, de 0,751 à 2,553 kg/m2 . Les mesures réglementaires en vigueur concernent la taille minimale de capture (6 cm), et une période de fermeture de la pêche de 8 mois. Les observations faites suggèrent de maintenir ces dispositions. Il est également proposé de créer une licence de pêche pour des pêcheurs professionnels, et de maintenir une pêche de loisir.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2003/acte-6527.pdf
http://archimer.ifremer.fr/doc/00000/6527/

Éditeur(s) : Office scientifique et technique des pêches maritimes
Résumé : This fourth part deals with the following points: - Industries related to fishing: - Curing, salting and canning - Processing of by-products - Refrigeration - Processing of seaweed - Oyster farming, mussel farming and shellfish farming - General survey of maritime fishing regulation in France
Cette version du Manuel des Pêches Maritimes françaises a été éditée en 1936 par l'Office des Pêches Maritimes. Les auteurs ont essayé de préciser quelle était alors la situation technique de l'industrie à laquelle étaient consacrées leurs études. Ce quatrième fascicule traite des points suivants: - Les Industries annexes de la pêche : - Fumage, Salage et Conserve - Traitement des sous-produits - Frigorification - Traitement des Algues marines - L'Ostréiculture, la Mytiliculture et la Conchylicultrice - Aperçu sur la réglementation de la pêche maritime en France
Mémoires de l'Office des Pêches Maritimes (1245-558X) (Office scientifique et technique des pêches maritimes), 1936-04 , Vol. Série spéciale , N. 12 fasc.4

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1936/rapport-1738.pdf
http://archimer.ifremer.fr/doc/00000/1738/

Éditeur(s) : Actes de colloques Ifremer, Tahiti, French Polynesia, 20 Feb - 4 Mar 1989, n°9, chap. 7, pp.57-66
Résumé : The first attempt to obtain artificial pearls from the black-lip pearl oyster Pinctada margaritifera in French Polynesia dates back to 1963. The pearl oyster culture has grown quickly especially since the eighties. This industry is now the first exportation in value of French Polynesia. 19 atolls of the Tuamotus island have at this time one or more farms and this activity has more and more attractiveness. The rise of this industry has consequently a lot of socio-ecomic repercussions on these atolls. However, as a young industry, the technics and the development are not always controlled and a lot of problems appeared these last years.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1989/acte-1494.pdf
http://archimer.ifremer.fr/doc/00000/1494/

Éditeur(s) : Springer
Résumé : The structure and summertime production of planktonic communities and the role of nondiatom planktonic cells were studied in coastal ponds, which are areas traditionally used for fattening and greening table-sized oysters. The abundance and biomass of nano-microplanktonic protists were determined at weekly intervals between February 1998 and February 1999 in a coastal pond without oysters in the French Atlantic coast near La Rochelle. The production of these microbiotas was determined in the summer period. The structure of plankton communities revealed the following observations: (1) microphytoplanktonic cells were mostly diatoms and dinoflagellates, (2) microzooplanktonic cells were mainly ciliates, and (3) nanoplanktonic cells were represented by pigmented (80-90% of the nanoplankton biomass) and colorless nanoflagellates. Diatoms were dominated by Naviculiineae. Dinoflagellates were dominated by Peridiniales. Oligotrichida were predominant in the ciliate community. Protist biomass levels were nine times higher from April to August (summer period 1033 mu g C L-1) than from September to March (winter period 114 mu g C L-1). Whatever the season, nanoflagellates were dominant in the water column (66 and 53% of the entire protist biomass in the summer and winter periods, respectively). Nanoflagellates represented the highest production of nano-microplanktonic communities (76% of carbon protist production) in the coastal pond in summer and showed the shortest generation time (7.1 h). Dinoflagellates came after nanoflagellates in production (19.5% of carbon protist production). Diatoms represented only a supplementary carbon resource available for higher trophic levels, whereas, until now, they were considered as the principal food of oysters in coastal ponds. Ciliates were a small source of carbon, but their growth rate was high. We suggest, first, that nanoflagellates represented the primary resource available in the pond and could constitute an important food resource for higher trophic levels, such as oysters, farmed in this type of pond. Overall, the system appeared to be more autotrophic than heterotrophic. Because inorganic nutrients are quickly exhausted in a semiclosed pond, pigmented flagellates dominated the carbon biomass, production and biomass of bacteria were high (thus, the microbial food web appeared to be active in this pond), and mixotrophy seemed to be an important trophic mode there.
Microbial Ecology (0095-3628) (Springer), 2007-05 , Vol. 53 , N. 4 , P. 537-548

Droits : 2007 Springer
http://archimer.ifremer.fr/doc/2007/publication-2641.pdf
DOI:10.1007/s00248-006-9087-z
http://archimer.ifremer.fr/doc/00000/2641/

Éditeur(s) : Conseil International pour l'Exploration de la Mer (CIEM), C. M. 1975/K: 21
Résumé : Following our aim of developing oyster culture in French Guyana and studying the different options available to increase a stock of new oyster species, we were lead to search for possible parasites in Crassostrea rhizophorae. These oysters from the French Guyanese coasts host some gregarine Nematopsis sp. spores, characterized by Comps, Grizel and Tige (1972). Through this work, we conducted some experimental infestation trials between Crassostrea rhizophorae spats parasited by these spores and the most common crab on metropolitan farms Carcinus maenas.
Poursuivant les objectifs de développement de l'ostréiculture en Guyane et étudiant les possibilités d'accroissement d'un stock constitué de nouvelles espèces d'huîtres, nous avons été amenés à rechercher d'éventuels parasites chez Crassostrea rhizophorae. Ces huîtres des côtes de la Guyane française abritent des spores de Grégarines, Nematopsis sp. mises en évidence par COMPS, GRIZEL et TIGE (1972). Au cours de ce travail nous avons réalisé des essais d'infestations expérimentales entre du naissain de Crassostrea rhizophorae parasité par ces spores et le crabe le plus répandu sur les parcs à huîtres métropolitains, Carcinus maenas.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1975/acte-6290.PDF
http://archimer.ifremer.fr/doc/00000/6290/

Éditeur(s) : 1st International Biennal Conference on Warm Water Aquaculture - Crustacea 02/9-11/83 Brigham Young University. Hawai
Résumé : Until recently, mollusc production in French Polynesia was only based upon fishing, for local consumption of edible bivalves mainly the oyster Saccostrea cucullata and for the exportation of pearl-oyster shells. As a consequence of parasitism problems on local oysters, a mollusc program was initiated by developping hatchery technics on introduced species of edible bivalves, Saccostrea echinata and Perna viridis, and cultivation methods in specialyy fitted up areas. Concerning pearl oyster Pinctada margaritifera the traditional shell production activity was recently reorganized to produce black culture pearls, inducing an increased demand of young implantable pearl-oysters. Hatchery spat production proved to be unsuccessful, and technics of collection and cultivation in lagoons were set up to supply the pearl oyster farming industry, and face the depletion natural stock. [NOT CONTROLLED OCR]

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1983/acte-4449.pdf
http://archimer.ifremer.fr/doc/00000/4449/

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
The present study tested different sounds that could disturb eagle rays (Aetobatus ocellatus) during their foraging activities at Moorea, French Polynesia. Results showed that artificial white sound and single-frequency tones (40 Hz, 600 Hz or 1 kHz) did not have an effect on rays (at least 90% of rays continued to forage over sand), while playbacks of boat motor sound significantly disturbed rays during foraging activity (60% exhibited an escape behaviour). Overall, our study highlighted the negative effect of boat noises on the foraging activity of eagle rays. These noises produced by boat traffic could, however, have some positive effects for marine aquaculture if they could be used as a deterrent to repel the eagle rays, main predators of the pearl oysters.
Notre étude teste différents types de sons qui pourraient perturber les raies-aigles (Aetobatus ocellatus) pendant leur prise de nourriture dans le lagon de Moorea, en Polynésie française. Les résultats montrent que le bruit artificiel blanc ou des fréquences uniques (40 Hz, 600 Hz ou 1 kHz) n’ont aucun effet sur les raies (au moins 90 % des raies continuent de se nourrir dans le sable), tandis que l’enregistrement d’un moteur de bateau les perturbe significativement dans cette activité (60 % des individus ont un comportement de fuite). Notre étude met ainsi en évidence l’effet négatif des bruits anthropogéniques sur les activités de nourrissage des raies-aigles. Ces bruits produits par les bateaux pourraient néanmoins avoir un effet positif pour l’aquaculture marine s’ils pouvaient être utilisés comme répulsifs des raies, principaux prédateurs de l’huître perlière.
ISSN: 1631-0691

Droits : http://creativecommons.org/licenses/by-nc-nd/
hal-01297683
https://hal-univ-perp.archives-ouvertes.fr/hal-01297683
https://hal-univ-perp.archives-ouvertes.fr/hal-01297683/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01297683/file/1-s2.0-S1631069116000020-main.pdf
DOI : 10.1016/j.crvi.2016.01.001

Éditeur(s) : Académie des Sciences
Résumé : Along the French Guiana coast, mainly in the Monsinéry River, there are populations of natural oysters belonging to the species Crassostrea rhizophorae (Guilding). Within the scope of the growth of oyster farming in Guiana, we researched possible parasites of these oysters that are still little studied. This work, conducted based on living and set samples, allowed us to highlight the presence of nematops spores.
Sur la côte de la Guyane française, principalement dans la rivière de Montsinéry existent des populations d'huîtres naturelles appartenant à l'espèce Crassostrea rhizophorae (Guilding). Dans le cadre du développement de l'ostréiculture en Guyane, nous avons recherché des parasites éventuels de ces huîtres encore peu étudiées. Ce travail mené à partir d'échantillons vivants et fixés nous a permis de mettre en évidence la présence de spores nématopsidiennes.
Comptes Rendus Académie Sciences Paris (Académie des Sciences), 1972-09 , Vol. 275 , N. 15 , P. 1693-1695

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1972/publication-3008.pdf
http://archimer.ifremer.fr/doc/00000/3008/

Éditeur(s) : Elsevier Science Bv
Résumé : We developed a growth model for Crassostrea gigas oyster shells based on the use of in situ temporal manganese markings to calibrate natural cathodoluminescence (CL) changes in the shell hinge sections. A 30 min to 4-h exposure period with Mn2+ (90-120 mg l(-1)) was sufficient to create a detectable mark in the shells. This makes the Mn2+ markings the fastest mollusc shells marking technique to date. The natural CL from juvenile and adult shells cultured in four standard shellfish-farming locations along the English Channel and French Atlantic coasts, exhibited a seasonal pattern (maximum CL intensity occurring during summer periods, minimum CL intensity occurring during winter). Hydrobiological data recorded at Baie des Veys site allows us to attribute the seawater temperature as the main parameter controlling CL of shells. Chlorophyll a and seawater manganese concentration were not decisive in the luminescence intensity of the shells. A relationship between oyster hinge growth and the length of shells makes the umbo investigations a promising tool for oyster-farming and/or wild stock assessments. Shell growth varied at spatial and temporal scales (higher growth rates were observed during summer-autumn and lower during the winter period), depending on seawater temperature changes. Sub-monthly Mn2+ markings support the fact that shell deposition can occur under temperatures below 6 degrees C, which has to be taken into account for both shellfish production and environmental monitoring derived from chemical compositions of the shells. Finally, our results point out the efficiency of age and shell growth rate determination by CL analysis in further shellfish ecosystem researches.
Aquaculture (0044-8486) (Elsevier Science Bv), 2010-02 , Vol. 300 , N. 1-4 , P. 206-217

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00002/11300/7912.pdf
DOI:10.1016/j.aquaculture.2009.12.018
http://archimer.ifremer.fr/doc/00002/11300/

Éditeur(s) : Institut national agronomique Paris Grignon
Résumé : The flat oyster Ostrea edulis L. is the indigenous oyster of the Atlantic as well as the Mediterranean coasts of Europe. Its commercial exploitation dates back to Antiquity but its breeding is now threatened by two parasitic protozoa, among which Bonamia ostreae. Various aspects of the genetics of this species' natural and farmed populations have been studied with the aid of microsatellite markers. At first, the implementation and the screening of two partial genomic libraries made it possible to identify 28 new microsatellite loci. Analysis of the segregation of 12 of these loci and of two enzymatic loci shows that most microsatellite loci are transmitted in a Mendelian way, but some loci have significant segregation distortions. Moreover, seven linkage groups, of which four contain at least two markers, were identified in Ostrea edulis. The genetic variability of three populations selected for one or two generations for resistance to Bonamia ostreae was analysed with the aid of 5 microsatellite loci. In spite of the absence of genealogical data, we have shown that these selected populations were descended from a very low number of founding genitors (from 3 to 15 depending on the population) and for two populations, we were able to reconstruct the genealogy and the relationships between the individuals were identified. These selected populations have, in addition to a very low genetic variability, real and at times high levels of consanguinity. These results have a significant implication for the continuation of the selection programme (consanguinity management, augmentation of genetic variability by introducing wild genitors). The geographical structuring of the genetic variability of natural populations of Ostrea edulis has been analysed with the aid of 5 microsatellite loci on a sampling covering almost the entire distribution area of the species (from Norway to the Adriatic Sea). The results are consistent with those published in the literature and using enzymatic markers. The populations show a low level of differentiation that could correspond to a model of isolation by distance. The Atlantic populations, which have a reduced polymorphism, could be descended from post-glacial recolonisation from Mediterranean populations that had survived the glaciations of the Quaternary Period. The current distribution of flat oyster populations is surely also subject to anthropogenic activities. Finally, the genetic bases of the heterozygosis-growth correlation were studied in a natural population with the aid of enzymatic and microsatellite markers. Although leads favouring the direct contribution of enzymatic loci have been found, biases in the sampling design make it impossible to come to a formal conclusion. However, this study has made it possible to show that the capture of individuals over a short period (around ten days) leads to a sampling of a population descended from a very low number of founding genitors, in contradiction with the generally accepted idea that marine bivalve populations are large panmictic populations with significant, efficient numbers. These results confirm in a natural population the observations of a significant reduction of efficient sizes in hatchery populations.
L'huître plate Ostrea edulis L. est l'huître indigène des côtes européennes aussi bien atlantiques que méditerranéennes. Son exploitation commerciale remonte à l'Antiquité mais son élevage est aujourd'hui menacé par deux protozoaires parasites dont Bonamia ostreae. Différents aspects de la génétique des populations naturelles et cultivées de cette espèce ont été étudiés à l'aide de marqueurs microsatellites. Dans un premier temps, la réalisation et le criblage de deux banques génomiques partielles ont permis l'identification de 28 nouveaux locus microsatellites. L'analyse de la ségrégation de 12 de ces locus et de deux locus enzymatiques montre que la plupart des locus microsatellites sont transmis de façon mendélienne, mais certains locus présentent des distorsions de ségrégation importantes. Par ailleurs, sept groupes de liaison dont quatre contiennent au moins deux marqueurs ont été identifiés chez Ostrea edulis. La variabilité génétique de trois populations sélectionnées depuis une ou deux générations pour une résistance à Bonamia ostreae a été analysée à l'aide de 5 locus microsatellites. Malgré l'absence de données généalogiques, nous avons montré que ces populations sélectionnées étaient issues d'un très faible nombre de géniteurs fondateurs (de 3 à 15 selon les populations) et pour deux populations, la généalogie a pu être reconstituée et les liens de parenté entre les individus ont été identifiés. Ces populations sélectionnées présentent, outre une très faible variabilité génétique, des niveaux de consanguinité réels et parfois élevés. Ces résultats ont une implication importante pour la continuation du programme de sélection (gestion de la consanguinité, augmentation de la variabilité génétique par introduction de géniteurs sauvages). La structuration géographique de la variabilité génétique des populations naturelles d'Ostrea edulis a été analysée à l'aide de 5 locus microsatellites sur un échantillonnage couvrant presque toute l'aire de répartition de l'espèce (de la Norvège à la Mer Adriatique). Les résultats sont cohérents avec ceux publiés dans la littérature et utilisant des marqueurs enzymatiques. Les populations montrent un niveau de différenciation faible qui pourrait correspondre à un modèle d'isolement par la distance. Les populations atlantiques, qui présentent un polymorphisme réduit, pourraient être issues de recolonisation post-glaciaire à partir de populations méditerranéennes ayant survécu aux glaciations du Quaternaire. La répartition actuelle des populations d'huître plate est certainement aussi soumise aux actions anthropiques. Enfin, les bases génétiques de la corrélation hétérozygotie-croissance ont été étudiées dans une population naturelle à l'aide de marqueurs enzymatiques et microsatellites. Bien que des pistes en faveur de la contribution directe des locus enzymatiques aient été trouvées, des biais dans le dispositif expérimental ne permettent pas de conclure de façon formelle. Cependant, cette étude a permis de montrer que le captage d'individus sur une faible période (une dizaine de jours) conduit à l'échantillonnage d'une population issue d'un nombre très réduit de géniteurs fondateurs, en contradiction avec l'idée reçue que les populations de bivalves marins sont de larges populations panmictiques à effectif efficace important. Ces résultats confirment dans une population naturelle les observations de réduction importante des tailles efficaces dans des populations d'écloserie.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1998/these-1919.pdf
http://archimer.ifremer.fr/doc/00000/1919/

Éditeur(s) : Elsevier
Résumé : The aim of this study was to distinguish between sources of the complex variety of Marennes-Oléron Bay suspended particulate organic matter (SPOM) contributing to the tropho-dynamics of the Marennes-Oléron oyster farming bay. Basic biomarkers (Chl a, C/N and POC/Chl a ratios), carbon and nitrogen stable isotopes from SPOM were analyzed and the microalgae community was characterized. The sampling strategy was bimonthly from March 2002 to December 2003; samples were taken from an intertidal mudflat. Four main sources contributed to the SPOM pool: terrigenous input from rivers, neritic phytoplankton, resuspended microphytobenthos and periodic inputs from intertidal Zostera noltii meadows. Seasonal fluctuations were observed in both years of the study period: (1) SPOM collected in the spring of 2002 (δ13C = −250/00 to −230/00) was mainly composed of fresh estuarine inputs; (2) SPOM from the summer and fall of 2002 and 2003 was predominantly neritic phytoplankton (δ13C = − 220/00 to −190/00); (3) SPOM from the winter of 2002, spring of 2003 and winter of 2003 (δ13C = −21 to −230/00) was composed of a mixture of decayed terrigenous river inputs and pelagic phytoplankton, which was predominantly resuspended microphytobenthos. In the summer of 2003—the warmest summer on record in southern France and Europe—SPOM was particularly enriched for 13C, with δ13C values ranging from −140/00 to −120/00. Pulses in δ13C values, indicative of 13C-enriched decaying materials, extended into the fall. These were attributed to benthic intertidal inputs, including both resuspended microphytobenthos and Z. noltii detritus. Changes in SPOM sources in Marennes-Oléron Bay may lead to differences in the quality of the trophic environment available for reared oysters.
Estuarine, Coastal and Shelf Science (0272-7714) (Elsevier), 2008-07 , Vol. 78 , N. 3 , P. 576-586

Droits : 2008 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4313.pdf
DOI:10.1016/j.ecss.2007.11.001
http://archimer.ifremer.fr/doc/00000/4313/

Éditeur(s) : EDP Sciences
Résumé : A population of the invasive slipper limpet (Crepidula fornicata) has been spreading in the Bay of Mont-Saint-Michel (Western English Channel) for 40 years. Sidescan sonar, underwater video and quantitative sampling were conducted in 1996 and 2004 to document the widening geographic spread of the species over the bay. The limpet population grew by 50% during this period, to reach a fresh biomass of about 150 000 t. This local study analyses causes and effects of the spread and provides a typical example of the limpet spreading process. This population increase has significant effects on the environment in the most densely colonized area (modification to the sediment and biodiversity), leading to the emergence of a new benthic community. Anthropic dredging activities are among the causative factors of the spread but are also adversely affected by the invasion.
Depuis 40 ans, la population de crépidules (Crepidula fornicata) prolifère en baie du Mont Saint-Michel (Manche Ouest). Deux études réalisées en 1996 et 2004 ont permis de cartographier et d'estimer le stock de la population grâce à des moyens similaires : sonar à balayage latéral, vidéo sous-marine et prélèvements quantitatifs à la benne. Durant cet intervalle de temps, la biomasse a augmenté de 50 % pour atteindre 150 000 t dans la baie en 2004. Cette étude comparative a permis d'analyser les causes et les effets d'une telle prolifération et d'en montrer le processus général. Dans les secteurs fortement colonisés, les effets sur l'environnement sont particulièrement néfastes (modification du sédiment et de la biodiversité) et aboutissent à une nouvelle communauté benthique. Les activités de pêche aux engins traînants (dragues et chaluts) sont à la fois les principales responsables et les victimes de cette prolifération.
Aquatic Living Resources (0990-7440) (EDP Sciences), 2009 , Vol. 22 , N. 1 , P. 11-19

Droits : 2009 EDP Sciences
http://archimer.ifremer.fr/doc/2009/publication-6351.pdf
DOI:10.1051/alr/2009004
http://archimer.ifremer.fr/doc/00000/6351/

Résumé : Tahiti’s pearl farming industry plays a major socio-economic role in French Polynesia. In an increasingly competitive market where the production of high quality pearls becomes essential, research can help secure and ensure sustainable production. In that context, Ifremer, in close collaboration with the “direction des resources marines” (French Polynesian government agency) has developed research projects on the “sustainable development of pearl farming”. This program is organized along 3 axes: (1) understanding the animal physiology and initiating a genetically selective breeding program of donor oysters; (2) understanding pearl oyster larvae dispersal and recruitment; (3) understanding the molecular mechanisms underlying biomineralization processes during shell and pearl formation. It is in this frame that we have developed a highthroughput Expressed Sequence Tags pyrosequencing program on the calcifying mantle, combined with proteomic analyses of the shell and pearl. We analyzed 276738 EST sequences, leading to the constitution of a P. margaritifera mantle transcripts catalogue of 82 sequences potentially involved in biomineralization. Our results provided direct evidence that our ESTs data set covers a large number of the matrix proteins of P. margaritifera. In addition, our proteomic analysis enabled us to retrieve, in silico, all the sequences from P. margaritifera involved in the biomineralization process already published on databases. Integration of these two methods allowed, for the first time, the global composition of calcifying tissue and calcified structures to be examined in tandem.
Recent Advances in Pearl Research—Proceedings of the International Symposium on Pearl Research 2011.Edited by Shugo Watabe, Kaoru Maeyama and Hiromichi Nagasawa. 2013. ISBN : 978-4-88704-158-5. pp.184-194

Droits : 2013 TERRAPUB. All rights reserved.
http://archimer.ifremer.fr/doc/00167/27840/26049.pdf
http://archimer.ifremer.fr/doc/00167/27840/