The Shellfish Laboratory of Normandy (LCN : Laboratoire Conchylicole de Normandie) observed unusual hydrologic anomalies associated with important oyster mortalities during the winter of 1999. These anomalies were described as sudden salinity variations during the lidal cycle, particularly on the rising tide. Starting in 1996 a multi-parameter probe was used to monitor salinity, temperature and depth every 10 to 20 minutes in the inter-tidal zone. Alter data processing and filtering, two criteria concerning low salinity were chosen : amplitude and duration. Application of a cumulative function (Ibanez et al., 1993) to this time series data treatment showed the 3 year trend (1996-1999). Salinity variation data and climatic data were used in a multivariate... |