9781888569551-ch29

Proceedings of the Third World Fisheries Congress: Feeding the World with Fish in the Next Millenium—The Balance between Production and Environment

Waste Recycling in Fishpond Culture through Integrated Culture Systems

Yang Yi, C. Kwei Lin, James S. Diana

doi: https://doi.org/10.47886/9781888569551.ch29

With increasing demand of aquaculture products, intensive culture systems with high stocking density and protein-rich feed are increasingly popular. Because intensively cultured fish are typically fed formulated diets, trash fish, or slaughterhouse waste, the water quality in culture ponds deteriorates rapidly. Frequent water exchange is required to prevent detrimental consequences from accumulated wastes. The nutrient-rich effluents discharged to surrounding waterways through water exchange and harvest draining have become a major environmental concern because they accelerate the eutrophication of natural waters (Beveridge 1984; Ackefors 1986; Lin 1990).

In contrast, animal manure has long been used to grow fish in integrated farming, and chemical fertilizers have been added to ponds to stimulate the growth of plankton, which are food for herbivorous and omnivorous fish in ponds (Pillay 1990; Edwards 1991). Because the effluents from intensive-culture ponds are abundant in rich nutrients and planktonic organisms, they can be reused to generate natural foods for filter-feeding fish species at low cost in ponds in an integrated fashion, thus making aquaculture more profitable to farmers (Lin et al. 1997).

In an attempt to mitigate environmental impact of intensive aquaculture and to increase the economic incentive of integrated aquaculture, researchers at the Asian Institute of Technology (Thailand) and the University of Michigan have developed integrated cage-cum-pond and pencum-pond culture systems (Lin 1990; Lin and Diana 1995; Yi et al. 1996; Yi 1997; Yi and Lin 2001; Yi et al. 2003).

Integrated cage-cum-pond culture is a system in which high-value fish species are fed artificial diets in cages suspended in ponds while filter-feeding fish species are stocked in open water to use the natural foods derived from cage wastes. This system has been developed using combinations of hybrid catfish Clarias macrocephalus × C. gariepinus and Nile tilapia Oreochromis niloticus (Lin 1990; Lin and Diana 1995) and different sizes of Nile tilapia (Yi et al. 1996; Yi 1997; Yi and Lin 2001).

Integrated pen-cum-pond culture is a system in which a fishpond is partitioned into two compartments, using netting material, to separate fed fish and filter-feeding fish and to use natural foods derived from wastes of feeding with artificial diets. This system has been developed using a combination of hybrid catfish and tilapia (Yi et al. 2003).

Hybrid catfish and Nile tilapia were used to develop the integrated cage-cum-pond and pen-cum-pond culture systems because they are commonly cultured freshwater fish in Thailand; annual production is 44,100 t and 76,100 t, respectively (DOF 1997).