D. Terziyski1*, H. Kalcheva2, A. Ivanova1, R. Kalchev2
1Institute of Fisheries and Aquaculture, 248 Vasil Levski, 4003 Plovdiv, Bulgaria
2Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 2 Gagarin, 1113 Sofia, Bulgaria
(Manuscript received 8 November 2015; accepted for publication 26 January 2016)
Abstract. Three years studies (2004 – 2006) on the main biotic parameters (chlorophyll-a, phytoplankton biomass, zooplankton biomass and bacterioplankton biomass) in carp fish ponds were carried out. The aim of the study was to investigate the biotic factors and the effect of manuring on the fish ponds. The relative changes in these factors in case of fertilization with manure 3000 kg.ha-1 or without fertilization were determined. The impact of fertilization as bottom-up melioration on some biotic factors was proven by means of paired non-parametric Wilcoxon test with following significant differences: higher levels of chlorophyll-a and higher phytoplankton biomass in fertilized ponds. Zooplankton biomass was higher in fertilized ponds, but the differences were statistically insignificant. Bacterioplankton biomass was higher in the fertilized ponds, which is an indication that the applied melioration does not lead to overload of organic matter in the ponds.