Livestock - Fish culture (Method for recycling farm waste)

T Bimol Singh *

Fish farm at Kakching, Laipham Loknung Pukhri in October 2016 :: Pix - Armando Bond

In livestock - fish farming, the excreta of chick, duck, pig and cattle are either recycled for the growth of fish food or serve as direct food for fish. The income realized in integerated fish farming is more than that of exclusive fish farming in ponds. Integeration of fish farming can be done with pig farming or pig and chick farming in two-tier system.

The droppings from the chick in the upper panel form a direct food source for pigs. The wastes from the pig and the chick finally fertilize the fish pond. Pigsties can be constructed near the bund of the pond.

However, they can also be constructed in a nearby place where the urine and dung of pigs are first allowed to the oxidation tanks (digestion chambers) of bio-gas plants for the production of methane for household use.

The liquid manure (slurry) is then discharged into the fish ponds through small ditches running through pond bunds. Pig dung contains more than 70% digestible feed for fish.

The undigested solids present in the pig dung also serve as direct food source to tilapia and common carp. A density of about 40 pigs has been found to be enough to fertilise a fish pond of one hectare area.

The optimum dose of pig manure per hectare has been estimated as five tonnes for a culture period of one year. Fish like grass carp, silver carp and common carp (1:2:1) are suitable for integration with pigs. A fish production of 6,000 kg/ha could be achieved under a stocking density 10,000 fish fingerling/ ha in a culture period of ten months.

Duck integrated with fish farming is a highly profitable venture as it greatly enhances the animal protein production in terms of fish and duck per unit areas. Ducks are known as living manuring machines.

The duck droppings contain 25 per cent organic and 20 per cent inorganic substances with a number of elements such as carbon, phosphorus, potassium, nitrogen, calcium etc.

Hence it forms a very good source of fertilizer in fish ponds for the production of fish food organisms. Ducks eradicate the unwanted insects snails and their larvae which may be the vectors of fish pathogenic organisms and water-borne disease causing organisms infecting human beings.

Ducks also help in releasing nutrients from the soil of ponds particularly when they agitate the shore areas of the pond. The nitrogen rich duck manure enhance both phyto and zooplankton production.

Phytoplankton feeding silver carp and zooplankton feeding catla and common carp are ideal for duck-fish culture. A stocking density of 20,000 fish seeds / ha in a culture period of 90 days with the fish production of 2,000 kg/ha has been obtained in duck-fish culture.

Chick droppings that are rich in nitrogen and phosphorous would fertilize fish ponds. Poultry sheds constructed above the water level using bamboo poles would fertilize fish ponds directly.

With a stocking density of 5,000 giant freshwater prawn (Macrobrachium rosenbergii) and 1,500 silver carp in one hectare area, a harvest of 600 kg of freshwater prawn and 600 kg of fish in four month culture period can be obtained. The number of chicks used for this system is about 400/ ha.

Cattle-fish farming is similar to pig-fish farming. Cow sheds may also be constructed in the vicinity of fish ponds and the slurry from the biogas plants may be discharged into fish ponds as in the case of pig-fish culture.

Countries like China, Taiwan and Philippines have undertaken the integrated fish farming on a commercial scale and obtained considerable fish yields.