EXTREMOS NEGATIVOS DO NÍVEL DO MAR DURANTE O INVERNO E A INFLUÊNCIA NO MEXILHÃO Perna perna DO COSTÃO DO MARUJÁ – CANANÉIA/SP:

The study shows an interdisciplinary approach through associations of the influence of the physical environment over the biological one in which negative extreme sea level events (or low tide extremes), due to low-frequency atmospheric forcing, explain part of the variability of the Perna Perna mussel collected on the coast of Cananeia/SP-Brazil during the winters from 2014 to 2016. The low-frequency atmospheric forcing acted in a constructive way, amplifying the negative anomalies of the sea level and destructive, reducing the influence of the astronomical forcing and the inverted barometer when both were favourable in increasing the variable. Though the composition technique the mean behaviour of the atmosphere and ocean in the 96 and 48 hours before the events and during their hours of occurrence was analysed. The events were associated with the passage of a transient anticyclone with northeast winds parallel to the coast due its position nearest to the study region. This contributed to the cooling of the sea surface temperature in the study region by the displacement of coastal waters to more distant regions. The correlation between the anomalous time series of sea level and mussel relative abundance index (the Capture Per Unit Effort Index, CPUE), without the linear trends, showed a moderate, negative and statistically significant relationship during the periods in analysis.  Thus, it is suggested that the persistence of low tide provided a favourable environment for less effort and collecting time, consequently, greater the availability of the mussel in the study region.