A Microcosm Multitrophic Aquaculture System

Abstract

Environmental degradation has continued to increase in the last decade, requiring us to put increasing efforts into environmental mitigation, including in terms of food production. Future food production must be able to minimize the use of fresh water, fertilizers and pesticides, and reduce soil erosion. The Multitrophic Aquaculture System (MAS) approach could be one positive solution to this problem, by cultivating multitrophic organisms in the same system. This study aims to present details of the processes involved in implementing MAS on a microcosm scale that is currently underway. In the future, this system will be scaled up to in-situ level using brackish water ponds. In the present study, red seaweed Gracilaria changii was used as an autotrophic organism while the grouper Epinephelus fuscoguttatus as a heterotrophic organism. There are two treatments and one control, each with three replicates. This study shows that the system developed works well enough for seaweed. Seaweed seems to grow well, even though the growth rate is still low. Groupers, which are in the same system, are also in quite good condition, although some groupers showed low appetite, most likely due to low oxygen supply and excessive nutrition in the water. These challenges may be overcome by using higher seaweed stocking density. The system can maintain several water quality parameters, such as pH, at optimal level.