PHYTOPLANKTON COMPOSITION IN FISH FARMS ALONG THE EASTERN ADRIATIC COAST

• Main Author: Marija Tomec
• Format: Article
• Language: English
• Published: Sciendo 2006-10-01
• Series: Croatian Journal of Fisheries
• Subjects: net phytoplankton; fish farms; eastern adriatic coast
• Online Access: http://ribarstvo.agr.hr/articles/75683_SASTAV_FITOPLANKTONA_NA_UZGAJALI_TIMA_RIBA_UZ_ISTO_NU_OBALU_JADRANSKOG_MORA_hr.pdf

Investigations of net phytoplankton composition were performed at three fish farms situated at the northern, middle and southern part of the eastern Adriatic Sea coast, respectively. In the northern part investigations were conducted in the Limski kanal, in the middle part at the Ugljan island and in the southern part in the place Drače on the Pelješac peninsula (Figure 1). At all three localities fish culture included mostly two species: gilthead sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax). Beside some physico–chemical parameters (sea water temperature, salinity) special attention was placed on the examination of qualitative net phytoplankton composition, which was conducted in the period of May and November 2004 and May and October 2005. Samples were collected at the depths of 0. 5 and 4 meters. According to the physico–chemical parameters, sea water temperature was influenced by the temperature of the environment. Qualitative net phytoplankton composition consisted of 153 microphytic species belonging to the systematic compartments of Cyanobacteria, Chrysophyta and Dinophyta (Table 1). The most numerous algal group were diatoms or Bacillarophyceae (84 species or 55%) with relative frequencies of species from 1 to 7. Taxonomic composition of diatoms showed the community Chaetoceros–Rhizosolenia (Proboscia) as the dominant one. The second numerically most dominant compartment were Dinophyta (62 species or 401%) with dominant the species of the genera Ceratium and Protoperidinium. Relative frequencies of species was ranging from 1 to 7 (mass presence of specimens in the water column). From Cyanobacteria (4 species or 3%), only filamentous algae were determined, with individual presence in net phytoplankton composition. Qualitative net phytoplankton composition suggests the similarity of species composition in the water column at all investigated fish farms. From the obtained characteristics of net phytoplankton composition conclusion can be made that all investigated localities constituted stable ecosystems.