Picture of the hydrological state in Lesina coastal lagoon

Lesina Lagoon, located in the north of the Apulia region (Italy), is a shallow coastal lagoon with average depth of 0,7 m and area of 50 km2. Lagoons play a key role as nursery ground for euryhaline fish species most of them having a commercially value. Consequently, it is very important the management and preservation of these environments. The recruitment period of 0-group migrant species is from October to May. Physicochemical parameters, inorganic nutrients and chlorophyll a were measured in 129 stations during only one campaign of measurements (October 2006), at the beginning of fry ascent period. Results are presented to examine spatial variability in physical and nutrients sources within the lagoon during an instant sampling, as a picture. On the basis of salinity gradient and nutrient concentrations, this preliminary study identified three different zones in the lagoon: West Zone characterized by higher salinities; Central Zone with lower salinity and lower inorganic nutrients concentration and East Zone with higher salinity and higher nutrients load and chlorophyll a concentrations. Longitudinal distributions of surface salinity and chlorophyll a may be depended on freshwater runoff. The freshwater inputs are distributed along the southern system representing a continuous source of nitrates and silicates mainly in East Zone.