Philippe Goulletquer

Open Atlantic Coast of Europe — A Century of Introduced Species into French Waters

This paper aims to establish a comprehensive list of exotic species introduced into Atlantic French waters over the last century as well as their origin, and the vectors involved in the process. At least 104 nonindigenous species have been recorded in the Atlantic and Channel coastal waters. Among those species, only a few (Bonamia ostreae, Crepidula fornicata) have resulted in highly significant negative impacts and side-effects on the coastal activity. In contrast, the introduction of the Japanese oyster Crassostrea gigas can be considered to be successful, sustaining a large industry counting more than 4,000 companies and 150,000 tons of yearly production. Over the last decade, French and European laws have strenghtened the controls over exotic species introductions, limiting their impacts. These new regulations and increased awareness from the scientific community with regard to coastal industry and biodiversity have reduced significantly the cases of deliberate introduction, while the risk analysis requirement has improved the overall management. However, in spite of these improvements, cases remain significant, mostly by accidental and/or increased vectors of introduction such as the ballast waters and sediment. Moreover, global changes should now be considered as a major issue, likely inducing future geographic distribution changes over a large European coastal range. Understanding the invasion population dynamics for exotic species remains a challenging research issue currently addressed by the French INVABIO multidisciplinary program.

THE CASE FOR SEQUENCING THE PACIFIC OYSTER GENOME

Abstract An international community of biologists presents the Pacific oyster Crassostrea gigas as a candidate for genome sequencing. This oyster has global distribution and for the past several years the highest annual production of any freshwater or marine organism (4.2 million metric tons, worth

Recommendations on methods for the detection and control of biological pollution in marine coastal waters

3.5 billion US). Economic and cultural importance of oysters motivates a great deal of biologic research, which provides a compelling rationale for sequencing an oyster genome. Strong rationales for sequencing the oyster genome also come from contrasts to other genomes: membership in the Lophotrochozoa, an understudied branch of the Eukaryotes and high fecundity, with concomitantly high DNA sequence polymorphism and a population biology that is more like plants than any of the model animals whose genomes have been sequenced to date. Finally, oysters play an important, sentinel role in the estuarine and coastal marine habitats, where most humans live, environmental degradation is substantial, and oysters suffer intense fishing pressures and natural mortalities from disease and stress. Consumption of contaminated oysters can pose risks to human health from infectious diseases. The genome of the Pacific oyster, at 1C = 0.89 pg or ~824 Mb, ranks in the bottom 12% of genome sizes for the Phylum Mollusca. The biologic and genomic resources available for the Pacific oyster are unparalleled by resources for any other bivalve mollusc or marine invertebrate. Inbred lines have been developed for experimental crosses and genetics research. Use of DNA from inbred lines is proposed as a strategy for reducing the high nucleotide polymorphism, which can interfere with shotgun sequencing approaches. We have moderately dense linkage maps and various genomic and expressed DNA libraries. The value of these existing resources for a broad range of evolutionary and environmental sciences will be greatly leveraged by having a draft genome sequence.

Ecophysiologie et bilan énergétique de la palourde japonaise d'élevage Ruditapes philippinarum

Adverse effects of invasive alien species (IAS), or biological pollution, is an increasing problem in marine coastal waters, which remains high on the environmental management agenda. All maritime countries need to assess the size of this problem and consider effective mechanisms to prevent introductions, and if necessary and where possible to monitor, contain, control or eradicate the introduced impacting organisms. Despite this, and in contrast to more enclosed water bodies, the openness of marine systems indicates that once species are in an area then eradication is usually impossible. Most institutions in countries are aware of the problem and have sufficient governance in place for management. However, there is still a general lack of commitment and concerted action plans are needed to address this problem. This paper provides recommendations resulting from an international workshop based upon a large amount of experience relating to the assessment and control of biopollution.

Status and Trends

Rates of filtration and respiration both follow a nonlinear model based on temperature of the form: Y = a × (T−T0)c × e −b(T−T0 with maximal values at 15 and 20°C, respectively. Quantities of seston varying from 0 to 30 mg · 1−1 have no effect in reducing the filtration rate. > 8 mg · 1−1, ingestion is regulated by the production of pseudofaeces. Maximal assimilation efficiency is ≈ 78%, but this is considerably reduced when the mineral content of the water increases. Assimilation efficiency for the Manila clam is reduced at both high (> 10 mm3· h−1) or low (< 2 mm3· h−1) values of ingested ration. The estimated value of growth efficiency (75%) and values of growth efficiency derived from the model k1 = 33%, K2 = 51% are optimized when ingested volumes are between 1 and 2 mm3. Standard metabolism is estimated as 0.11 ml O2 · h−1. Zero growth efficiency occurs at a ration level of 2 J · h−1 for an adult. The individual energy budget shows that production is dependent more on temperature than on the energy value of the food. Comparison of calculated and measured production reveals differences resulting from the higher levels of seston found in the field. In particular, during the winter when the mineral content of the seston is high (90 mg · 1−1), there is a continuous loss of weight. This results from a lower assimilation efficiency together with production of pseudofaeces. Excretion of organic nitrogen varies throughout the year, ammonia representing no more than a mean of 29.8% of the total nitrogen excretion.

History, status, and future of oyster culture in France.

Our limited knowledge of the world’s biodiversity, coupled with the limitations of the current approaches to cataloguing biodiversity, are the main driving forces behind new approaches to species identification. Estimates of the total number of existing eukaryotic species range from the most conservative of 3.6 million to over 100 million, with a figure of 10 million favoured by most analysts as the nearest order of magnitude. To date, some 1.9 million species have been deposited in museums.

HYDROBIOLOGY OF THE MARENNES-OLERON BAY. SEASONAL INDICES AND ANALYSIS OF TRENDS FROM 1978 TO 1995

ABSTRACT The history of French oyster culture consists of a succession of developmental phases using different species, followed by collapses caused by diseases. The indigenous species Ostrea edulis was replaced first with Crassostrea angulata, then C. gigas. France is now the top producer and consumer of oysters in Europe, producing around 120,000 t of the cupped oyster C. gigas annually, and an additional 15001 of the flat oyster O. edulis. Cupped oysters are produced all along the French coast from natural and hatchery spat. Various structures are used to collect spat from the wild. After a growing-on period, oysters are cultivated by three main methods: (1) on-bottom culture in the intertidal zone or in deep water, (2) off-bottom culture in plastic mesh bags in the intertidal zone, or (3) suspended culture on ropes in the open sea. The main recent development is the increasing use of hatchery oyster spat, especially triploids. Almost all oyster production is sold fresh and eaten raw straight from the shell. There is marked seasonality in sales, with the majority being made during Christmas and New Year. Abundant production and the lack of market organization induce strong competition among the production areas, causing prices to fall. Oyster farmers have developed strategies of sales promotion and regional quality labeling to overcome this difficulty. There are numerous production hazards, including environmental crises (microbiological pollution), unexplained mortality, and overstocking, and recent problems with toxic algae have disrupted oyster sales. However, oyster culture has many assets, including a coastal environment offering favorable sites for mollusc growth and reproduction. Oysters have been consumed in France since ancient times, and their culture is now well established with a concession system that favors small family firms. There is a young, well-educated farmer population, with technical expertise and savoir faire. Careful seawater quality monitoring ensures good consumer protection, and research is making innovative contributions (selection and polyploids). These points and opportunities for market expansion should bolster this industrys future, although the problem of toxic algae, probably linked to global warming and anthropogenic factors, and the threat of new diseases, pose vital questions for future research.

Comparative physiological energetics of two suspension feeders: polychaete annelid Lanice conchilega (Pallas 1766) and Pacific cupped oyster Crassostrea gigas (Thunberg 1795)

A hydrobiological monitoring network has been in place since 1977 in the Bay of Marennes Oleron (France). Data collected for physical variables (seawater temperature, salinity, oxygen concentration), nutrients (ammonium, nitrates, phosphates and silicates) and chlorophyll a and pheophytin, from 5 representative stations in the bay, were examined by time-series analysis (Census II method) to study seasonal variability and trends. The seasonal changes were similar over the entire Marennes Oleron Bay for all variables and were chiefly influenced by fluxes in the Charente river. The seasonal range reached 180 units for nitrates and 70 and 100 units respectively for phosphates and silicates. These values were similarly mostly correlated with the Charente River fluxes. With regard to long-term trends, seawater temperature has shown a significantly increasing trend close to 2 °C over 18 years. At the same time, a 1 °C gradient was demonstrated from the northern to the southern part of the Bay. The salinity trend varied between 30 and 34‰for all stations. The trend for oxygen concentration, ranged from 90 to 100% but during a specific two year period (1980–1982) saturation decreased to 76% in the northern part of the Bay.The trend analysis for nitrates showed a significant relationship with the water output level of the Charente. Phosphate inputs have been irregular during the two last decades which has affected primary productivity along the coastline (e.g., spring 1979–1983; 1990; 1993–1995).Since 1988, a significant increasing trend for ammonium was observed at the mouth of the Seudre river (4 μmoles l−1 ) while other stations were well below this, ranging from 1 to 3 μmoles l−1 . This should be considered as an indicator of seawater deterioration within the southern part of the Marennes Oleron Bay.

Shellfish farming and Coastal Zone Management (CZM) development in the Marennes-Oléron Bay and Charentais Sounds (Charente Maritime, France): A review of recent developments

Abstract Feeding competition between the Pacific cupped oyster Crassostrea gigas and the polychaete Lanice conchilega was studied by assessing the polychaete suspension feeding activity. Retention efficiency was estimated by comparing particle size distributions at the output of experimental chambers containing the species and controls. Although particles ranging from 4 to 12 μm were collected by L. conchilega , no upper threshold or maximum retention rate was reached within this range. In contrast, C. gigas showed retention starting at 2 μm, and reaching an upper threshold at 6 to 8 μm. Based on our results, feeding competition is likely to occur between C. gigas and L. conchilega . Standardised filtration rates reached 0.225 l h −1 g dmw −1 (±0.08) for L. conchilega and 2.43 l h −1 g dmw −1 C. gigas for animals of 1 g dry meat weight (dmw). Assimilation rates, 0.44 for L. conchilega and 0.49 for C. gigas , were similar for the two species. Respiration rates were estimated at 0.113 and 0.68 ml O 2 h −1 for L. conchilega (Allometric coefficient=0.534) and C. gigas respectively. Therefore polychaete scope for growth (SFG) (4.01 J h −1 g dmw −1 ) was significantly lower when compared with C. gigas SFG (61.96 J h −1 g dmw −1 ). The impact of the L. conchilega population on that of cultivated oysters was evaluated from these results and field population assessment of both species. Based on field population estimates, L. conchilega was responsible for a 19% decrease in the carrying capacity and 30% of the oxygen depletion from the total activity of both species. However, L. conchilega SFG was only 16% of that of the C. gigas population. Several hypotheses regarding population interactions are discussed.

Comparative analysis of oxygen consumption rates between cupped oyster spat of Crassostrea gigas of French, Japanese, Spanish and Taiwanese origins

France is currently one of theleading shellfish production countries inEurope, harvesting more than 150,000 metrictons of the Pacific cupped oyster (Crassostrea gigas) and 60,000 tons ofmussels (Mytilus edulis and M.galloprocincialis) each year. Amongrearing areas, the Charentais Sounds and theMarennes-Oléron Bay rank first in Europe,with an annual production of 40,000 and 15,000tons of oysters and mussels respectively. Morethan a third of French production is marketedfrom the Marennes-Oléron area. As naturalC. gigas and M. edulis spatfall islimited to the Atlantic coast, theMarennes-Oléron Bay and the CharentaisSounds play a critical role nationally,representing more than half of French oysterand mussel spat production. The stockingbiomass in this area was recently estimated at125,000 and 20,000 tons of oysters and musselsrespectively. This biomass is deployed over4,000 ha of leasing grounds along the coastalarea and 3,000 ha of wetlands (oyster ponds),which are environmentally sensitive and subjectto numerous recent regulations.Although a traditional, century-old activity,the shellfish industry now has to addressvarious new internal and external constraintsaffecting overall economic yield andsustainability. These include the management offreshwater inputs into the coastal area,impacted at the watershed level by agriculturefrom a qualitative and quantitative point ofview (e.g. irrigation activity). Moreover, theCharentais Sounds need to remain competitive onthe open market with other French and Europeanproduction sites, whereas its biological yieldremains one of the lowest in France. This hasprompted the industry to optimize spatialdistribution, restructure current leasinggrounds and assess new management practices aswell as new rearing techniques (offshore, longlines), which have led to conflicts overavailable space. In addition to technicalconstraints, local, national and Europeanregulations have increased significantly. Thecoastal law, water law, bird directives, andregulations concerning the preservation ofnatural habitats, wild flora and fauna andprotected areas are among the acts likely tohave an impact on the shellfish industry in thenear future.These internal and external constraints onaquaculture sustainability are analyzed, andcertain case studies in the Charentais Soundsthat have led to user conflicts are reviewed.The diversity of habitats, human activities andinterests along this coast have resulted inhighly complex situations in which somemanagement attempts have been partly successfuland others have failed. These managementoptions are analyzed, and ongoing newapproaches are described, including cooperativestrategies among marine biologists,sociologists, economists, managers, coastalusers, and the shellfish industry. Based onthis analysis, requirements for the developmentof an integrated CZM plan in the CharentaisSounds are suggested, including the use of aproactive approach, geomatics and operationalmodels, as well as the development ofintegrated decision making structure to developCZM and then, the use of a stepwise model ofagreement-focused negociation for furtherconsensus building.