Consequences of anthropogenic eutrophication in the Kastela bay (Adriatic Sea)

Ivona Marasovic
Institute of Oceanography and Fisheries
Split
Croatia
Email: marasovic@izor.hr

Kaštela Bay is a semi-enclosed coastal bay in the Middle Adriatic a total volume of 1,4 km3. It receives a great amount of untreated waste waters, both domestic and industrial. The first data of on the phytoplankton of the Kaštela Bay can be traced back to some seventy years ago. Systematic studies of phytoplankton and other biotic and abiotic parameters have been carried out ever since 1956. The first changes in the bay such as a gradual increase in primary production, density of phytoplankton cells, change of the seasonal cycle and increase of chlorophyll a concentrations were observed at the end of seventieth. The structure of phytoplankton community has been changed and dinoflagellate species have become dominant rather than diatoms. At the beginning of eighties these changes have become rather serious since minor or more severe red tides occurred on several occasions accompanied by the mortality of the marine organisms from time to time. At the beginning of ninetieth the first shellfish toxicity were recorded in the bay (DSP).