Abstract
In this study, we adopted the Ambul technology which is a traditional knowledge of indigenous people of Kalimantan island-Indonesia to grow various crops on a floating decomposed water hyacinth on wetland ecosystem. The study was focused on the effect of water hyacinth cover on water quality and the growth of aquatic microorganism community. We also tested the utilization of water hyacinth as additional food supply for a cage cultured fish. The investigation of the effect of water hyacinth cover on water quality and the growth of aquatic microorganism community was conducted in 2 experimental ponds nearby our laboratory. One pond was treated with water hyacinth, whereas the other was kept intact without water hyacinth, as a control. Water quality in terms of phosphate, nitrate and BOD and also aquatic microorganisms particularly copepod communities were monitored at both ponds prior and after the introduction of water hyacinth. For the purpose of using water hyacinth as additional food supply for cage cultured fish, we established an experimental fish culture in water hyacinth treated and in non water hyacinth treated cages. Fish growth in terms of their weight and length were monitored for 3 months.
Our study revealed that water hyacinth effectively absorbed phosphate and reduced BOD and its cover promoted more abundant copepod community. Cultured Osphronemus gouramy fishes supplied with additional food of water hyacinth grew much faster than those cultured in non water hyacinth treated cages. Based on our results, we proposed that the adopted Ambul principle could be used as an alternative technology to overcome the organic water pollution problem both in lake and river ecosystems.
