Environmental and biotic variables in carp (Cyprinus carpio) ponds: organic vs. conventional management

Abstract

Organic aquaculture, including carp pond farming, is of growing importance. One of its main characteristics is the health and quality of water environments and maintenance of their biodiversity. In 2013–2014, four organic carp ponds (ORG) in the Waldviertel region (Austria) and four conventional ponds (CONV) in the Třeboň region (Czech Republic), located in the Lainsitz (Lužnice) river basin, were monitored for basic environmental variables, namely hydrochemical and hydrobiological determinants. The aim of this study was to evaluate the performance of organic carp farming technology in the amelioration of carp pond aquatic environment. Aside from temperature, which was probably related to different altitudes, the comparison of physico-chemical environmental variables showed no significant differences between organic and conventional ponds, though dissolved oxygen concentration and saturation, along with turbidity, were higher in ORG ponds, and conductivity was slightly higher in CONV ponds. The mean cumulative richness of zooplankton species was significantly higher in ORG ponds. However, when comparing average richness between both management types, there were significantly fewer rotifer species in ORG fishponds (ORG = 10, CONV = 15; p 0.05), while its biomass was higher in CONV ponds (CONV = 5.31 ± 0.48, ORG = 4.45 ± 2.17 g m−2; p > 0.05).