For the treatment ponds, fish was assumed to filter the 80% of particulate nitrogen (PN) from the shrimp pond effluent. Assuming the fish N assimilation efficiency was 24%, then 5% of original feed N would convert to fish biomass, while 16% of the original N would be excreted in the form of settling particles (8%) and dissolved nutrients (8%). At this rate, the fish pond effluent would contain 44% of the original N introduced by feeding, which was 4% of PN and 39% of dissolved nitrogen (DN). The seaweed production unit was estimated to remove the 90% of DN in fish pond effluent, thus taking up 36% of the original feed N. The final effluent would contain only 9% of the original N (5% PN and 4% DN). The flow diagram of nitrogen in the proposed integrated system is shown in