Zooplankton structure in two interconnected ponds: similarities and differences

• Published in: Ribarstvo Vol. 74; no. 1; pp. 6 - 13
• Main Authors: Špoljar, Maria, Tomljanović, Tea, Dražina, Tvrtko, Lajtner, Jasna, Štulec, Helena, Matulić, Daniel, Fressl, Jelena
• Format: Journal Article
• Language: English
• Published: De Gruyter Open 01.03.2016; Sciendo
• Subjects: Fish; Freshwater; Predation; Submerged macrophytes; Transparency; Turbidity; Croatia, Sutla River
• ISSN: 1848-0586; 1330-061X; 1848-0586
• DOI: 10.1515/cjf-2016-0002

The research of zooplankton diversity, abundance and trophic structure was conducted during the summer period in pelagial zone on the longitudinal profile of the Sutla River Backwater. Investigated site consists of two interconnected basins: transparent Upper Basin with submerged macrophytes and turbid Lower Basin without macrophytes in the littoral zone. In the Upper Basin, abundance and diversity of zooplankton in the pelagial was higher in comparison to the Lower Basin, with prevailing species of genus as microfilter-feeder, and genera of and as macrofilter-feeder rotifers. On the contrary, in the Lower Basin, crustaceans dominated in abundance. Microfilter-feeder cladoceran ( ) and larval and adult stages of macrofilter-feeder copepod ( ) prevailed in the Lower Basin. Fish predation pressure was more pronounced in the pelagial of the Upper Basin, indicated by low cladoceran abundance in the surface layer. Although the studied basins were interconnected, results indicate significant (Mann-Whitney U test, p < 0.05) differences in the zooplankton structure as a potential result of the macrophyte impact on environmental conditions and fish predation pressure.