Hydrozoan epiphytes on Posidonia oceanica medows in the Engeceli bay (Karaburun peninsula) affected by fish farming activities

This study was carried out between September 2004 and May 2005. Posidoniaoceanica (L.) Delile rhizomes samples were taken by SCUBA from Mordogan-EngeceliHarbor and the reference stations which are not affected by aquaculture activities.Collected samples and their hydrozoan leaf epiphytes were examined in laboratory. Theobjective of the research is to find out the difference between Posidonia oceanicameadows situated 300 m from aquaculture activities and the meadows which were faraway from the Engeceli Bay. The depth ranges of the samples were 0-5 m, 5-10 m and10-15 m.Within the framework of this study, physico-chemical parameters of environment;phenological specifications of Posidonia oceanica meadows (i.e. shoot density; numbersof adult, intermediate and juvenile leaves; lenghts of collected adult leaves) andhydrozoan epiphytes settled on leaves of Posidonia oceanica were examined.Changes in ammonium nitrogene values among the physico-chemical parameters,variation in concentrations of total organic carbon content in sediment (TOC), differencesin shoot density of Posidonia oceanica meadows at selected sites and settlement intensityof Filellum serpens observed only on the samples collected from control site are thoughtto be the possible difference between two selected areas.