There are numerous socio-economic impacts associated with eutrophication including: • toxicity or mortality in commercial fish and shellfish species leading to reduced catches;
• loss of employment and income in fisheries related to re- duced resource base;
• loss of aesthetic value resulting from algal blooms; • loss of tourism related to deteriorating water quality; • loss of employment and income related to tourism, especially sport fishing; and
• loss of cultural heritage (UNEP/MAP/MED POL 2005).
Most susceptible to the negative impacts of eutrophication are semi-enclosed basins, estuaries and lagoons, where excess nutri- ents are not easily dispersed (UNEP/MAP/MED POL 2005).
Red tides are a problem for some Mediterranean fisheries. Fish- ing and mollusc farming in the northwestern Adriatic have been damaged by blooms of the dinoflagellate, Dinophysis spp., which causes Diarrhoetic Shellfish Poisoning (DSP). The occurrence of this organism has been responsible for temporary and pro- longed bans on the harvesting and sale of mussels in the coastal and lagoon areas of Emilia-Romagna (UNEP/MAP/MED POL 2005). Alexandrium tamarensis, a dinoflagellate that produces Paralytic Shellfish Poisoning (PSP) toxins has been observed in the northern Adriatic (UNEP/MAP/MED POL 2005).
The Initial Integrated Assessment data suggest that eutrophica- tion is still a localised phenomenon in the Mediterranean Basin. Better monitoring regimes and analysis of resulting data to de- termine trends will, in the future, allow robust statements of the effect of eutrophication on the ecology, as well as on fisheries and other valuable ecosystem services (UNEP/MAP 2012).
HUMAN PRESSURE, STATE AND IMPACTS ON MEDITERRANEAN ECOSYSTEMS