Relationshlp between the mucilage phenomenon and some concomitant environmental variables in the northern-Adriatic lagoon OF Stella Maris, Umag, Croatia

The appearance of mucilage episodes and some meteorological and oceano-graphic variables were daily monitored during a 1-year period in the shallow macro-tidal northern-Adriatic lagoon of Stella Maris, Umag (Croatia). The phenomenon than appeared in the seawater in the form of gelatinous flocks, patches and stringers of various size and colour was recorded from April to September 2005. The environmental data collected during that period (air and water temperature, wind force and wind direction, tides, water density and salinity, current speed and current direction) were compared by means of Principal Component Analysis (PCA) to the winter parameters when the mucilage was absent. From the results obtained using the PCA method, we assumed that the changes in current speed, wind force and wind direction during the spring and summer period were able to affect density, tides and salinity which then became decisive factors that contributed to the accumulation of the mucilage aggregates. Similar findings documented in the whole northern Adriatic are discussed in this paper.