Le microplancton des rivieres de Morlaix et de la Penzé

The Morlaix and Penzé River estuaries, are important oyster-farming areas on the north coast of Brittany. It was thus useful to study the different factors of the environment that oysters (O. edulis) inhabit to determine, if possible, their role in oyster growth and fattening. Our study gives results on surveys of the animal and plant species that make up planktonic communities in this area as well as on the relationships that may exist between fluctuation in community composition and variation in temperature and salinity, based on data collected between 1963 and 1967. In each estuary, four stations were chosen. Plankton was sampled in each of these stations (Figure 1) and also, for purposes of comparison, occasionally in another station called "Pot-de-Fer" located at the entrance of Morlaix. This study complements prior research carried out by Grall and Jacques (1964) on the dynamics and seasonal variation of plankton in the Roscoff area. (unverified OCR)