Periphyton-water quality relationships in fertilized fishponds with artificial substrates

The potential of periphyton-based aquaculture in southern Asia is under investigation in an extensive research program. This paper is a further analysis of data from two experiments carried out in that framework, to explore periphyton-environment relationships in the absence of fish grazing pressure. Factor analysis and ANOVA models applied to data matrices of water quality, plankton and periphyton parameters allowed identifying the underlying ecological processes governing this novel periphyton-based pond system. The system was dominated by changes in time, and the main sources of variability were periphyton biomass increase through the culture period and its effect on water turbidity, processes affecting pond oxygenation and processes leading to surface-depth differences in water quality. All those processes act at the same time but with different intensities and time patterns, and affect the measured variables in different ways. Conceptual models of the periphyton-environment relationships observed are presented in graphical form. The knowledge generated provides background information required for fish culture management in periphyton-based ponds. (C) 2003 Elsevier Science B.V. All rights reserved.