2015 was a year of transition initiating changes in how Ifremer monitors the health of marine molluscs. The monitoring process consists of 4 strands and serves 2 objectives.

Three strands have been put in place to meet the first objective.

Planned monitoring of mortalities and diseases of the Crassostrea gigas oyster using the RESCO 2 network.

Planned monitoring of blue mold Mytilus edulis mortalities and diseases using the MYTILOBS 2 network. These two networks focus on regular monitoring of animal health indicators at the sites.

Events monitoring of mortalities of other species of marine molluscs (the Mytilus galloprovincialis mussel included) using the REPAMO network 2. This network makes use of the data on mortalities reported by shellfish farmers or by professional fishermen to the decentralized services of the State, the Departmental Directorate of Territories and Sea.

One strand has been put in place to meet the second objective. The planned, targeted and risk-based monitoring of the introduction and establishment of Microcytos mackini in the Crassostrea gigas cupped oyster depends on the RESCO 2 network. This monitoring is based on regular follow-up of the Loix-en-Ré site. The surveillance applies to shellfish populations of commercial interest on the French coast whether they are farmed or wild.

The epidemiological unit may be a concession or an oyster farm, a hatchery-nursery, a natural bed, an area or part of an area. All epidemiological units can be sampled according to the given epidemiological surveillance protocol. Two types of data are collected in the REPAMO 2 network: information on the collection (commemorative) and results from analyses. For each epidemiosurveillance protocol, memorials are systematically collected by Ifremer field correspondents based on questionnaires developed as part of a quality approach. The animals collected are analyzed by the analytical section of Ifremer’s Pathology and Genetics Laboratory in La Tremblade. The analytical reference method recommended for the detection of pathogenic organisms of regulated diseases is histopathology. The number of samples analyzed makes it possible to compensate for the low sensitivity and specificity of this tool, especially for infectious agents other than parasites. Other diagnostic tools are used in addition. These include molecular biology techniques such as PCR but also cultures (bacterial spread - isolation of majority strains, parasitic in thioglycolate medium), in situ hybridization, electron microscopy transmission, characterization of species by sequencing.

Type de données :

le cadre du réseau ont permis dans certains cas de découvrir de nouveaux agents infectieux directement associés à de la mortalité (Vibrio harveyi sur Haliotis tuberculata par exemple) et de mettre en évidence la présence en France d'agents infectieux considérés jusqu'alors comme exotiques (Perkinsus olseni, Haplosporidium nelsoni, Bonamia exitiosa). Des différences de sensibilité vis-à-vis d'un agent pathogène ont pu être mises en évidence entre populations d'une même espèce.

Nombre de points d'observation ou de mesure :

non prévisible : dépend des déclarations des conchyliculteurs/pécheurs

Précision sur le type de donnée :

Étude des hausses de mortalité : Maintenir un état de veille à l’égard de toute maladie infectieuse affectant les mollusques

Paramètre(s) observé(s) ou mesuré(s) :

Tout organisme pathogène, en particulier ceux réglementés (par l'OIE, l'UE et la France), et les agents infectieux émergents

Résolution du (ou des) paramètre(s) :

30 moribonds et 30 vivants

Fréquence d'actualisation :

continue

Fréquence d'observation :

Variable