Marine Environment - Huitres Boyard

Zoning

The BOYARD oyster is farmed in a healthy environment. The production areas are classified in safety rating (zoning).

J.O: Extract from the decree of 21 July 1995 on the safety ratings and monitoring of the production areas and the live shellfish relaying areas:

Article 7: “Shellfish culture production zones are classified according to the results of a sanitary analysis “Zone Study”… …”The zone study, are completed if necessary by the results of self-controls as mentioned in articles 18 and 22 of the decree of 28 April 1994, it should allow a significant evaluation of microbiologic and chemical pollutants in terms of health risks”

Article 10: “The chemical contamination level of a production zone may be determined for a shell group, by dosing the chemical pollutants, such as lead, cadmium and mercury, in samples of shell species, taken on the zone.

Group Zoning: A, B, C And D

ZONE	Faecal coliform	Et E. Colis	Chemicals Contaminants
A	– 300/100 g of flesh	– 300/100 g of flesh	No risk of toxicity to the consumer
B	– 6000/100 g of flesh	– 4600/100 g of flesh	idem
C	– 60 000/100 g of flesh	– 46 000/100 g of flesh	idem
D	+ 60 000/100 g of flesh	+ 60 000/100 g of flesh	Unsatisfactory, zone subject to pollution or has not been under analysis

All EARL Boyard Roger et Sons parks are in zone A, that is, free from bacterial and chemical contamination. The water in our basin is of excellent quality so are our products.

The importance of the marine environment also comes from other marine ecology concepts, such as the composition of sea water, the physical and chemical parameters.

Marine ecology notions

The growth and survival of farmed oysters are related to physical and chemical parameters.

Physical parameters: temperature, pressure, colour, suspended solids (= turbidity)

Chemical parameters: salinity, ionic composition, pH, dissolved gases (oxygen, CO2, nitrogen), nutrients, some specific molecules (vitamins, amino acids, fatty acids, growth regulators), organic matter

Seawater composition: Besides the hydrological characteristics such as pH, salinity, temperature and oxygen, oysters are closely related to the phytoplankton composition. The nutrition of the bivalve is done by sea water filtration and the retention of micro-organisms of less than 50 microns.

Some of the phytoplanktonic algae present at sea and the marshes

The marshes and oyster claires

The ecosystem “oyster claires” (ground basins in salt marshes) is a confined environment. It is influenced by the weather, which is specially significant if the site is temporarily isolated from the rest of the hydraulic system. These basins are also characterised by a low volume / surface ratio. It is then interesting to follow the physico-chemical parameters of the water:

The water temperature follows that of the ambient air, with smaller variations due to the thermal inertia of the liquid. It influences the development of phytoplanktons as well as other parameters. The salinity is proportional to the temperature of the water.

Given the possible significant variations in parameters, a monitoring of the claire water is important. It is necessary that oyster farmers monitor the temperature, salinity and dissolved oxygen to prevent mortality. Moreover, he should also monitor the development of the navicule bleu, Haslea ostrearia, for the oyster greening process.