Many-year variations of the average salinity of the Sea of Azov

A brief review of studies of the hydrological regime of the Sea of Azov and approaches to assessing the average salinity—a key indicator of the state of its ecosystem is given. A database of salinity measurements at 47409 oceanographic stations over hundred years (from 1913 to 2014) were used to evaluate the sea-averaged mean annual salinity. The obtained values of the average salinity were found to differ from those published before because of the different approaches used to its calculation and different volumes of data involved. The difference was most significant for Taganrog Bay because of the high variability of its hydrological regime. Anomalies of the average salinity over period 1922–2014 were constructed, and the start of one more period of salinity increase in the Sea of Azov was recognized.