GENERAL GOOD MANAGEMENT PRACTICES IN FISH FARMING
Er Ritesh Pandey of JAGO KISAN JAGO.
The pre-requisite for the fish farming is the availability of perennial water
Selection of site:————-
For fish culture such a site should be selected where the water is available through a regular source like spring, river, channel, etc. or even waterlogged land may be reclaimed for this purpose. The soil should not be completely sandy but should be a mixture of sand and clay so that it has the capacity of retaining the water. Alkaline soils are always
better for good growth of fish. Before construction of pond, the physic-chemical properties of soil should be got tested from soil testing laboratory.
Construction of ponds: ——————-
The size and shape of the pond depends upon the availability of the land and type of production. For an economically viable project, the minimum size of pond should be 10m x 10m x 1.5 m and above. A typical pond should have an inlet for the entry of water fixed with wire mesh so as to prevent the entry of unwanted indigenous fauna and an outlet for overflow of excess water fixed with wire mesh to prevent the exit of stocked species. There should be a drain pipe at the bottom of pond and a harvesting pit to facilitate the harvesting and to dry the pond from time to time. The sides or dykes of the pond should be well compacted, sloppy and planted with grasses or herbs to protect them from erosion. The gullies and watershed area can also be converted into pond by raising an earthen dam.
Preparation of ponds ——————–
(i) Liming: ——————–
Liming of the pond is necessary to eradicate the harmful insects, micro-organisms, to render soil alkaline and provide calcium to the growing fish. If soil is not acidic, the lime can be used at the rate of 25 g per sq m and if soil is acidic, increase the quantity of lime by 50%. After broadcasting of lime in whole tank, it must be left dry for 4 days to one
week.
(ii) Manuring: —————
Manuring is done with the objective to increase the plankton which form the natural food of the fish. The rate of manure depends on the fertility status of soil. The organic manure such as cow dung is used @ 20 tonnes/ha i.e. 2 kg per sq m area in Palampur valley. Initial manuring is to be done with 50% of total required manure and subsequently the rest 50% should be used in the equal monthly installments. Fill the tank with water just after manuring and leave it for 12-15 days.
(iii) Control of aquatic weeds and predators: ———————
The algal blooms are sudden out-bursts due to higher manuring or organic effluent. These blooms liberate good amount of carbon dioxide leading to oxygen depletion which can cause large scale mortality. If reddish scum appears on the surface of the water, this means the outbreak of algal bloom. The manuring and artificial feeding should be stopped immediately and allow fresh water in the pond. If the algal blooms are in excess,
spray 3% copper sulphate solution selectively to worst affected areas of pond or superphosphate at the rate of 1 g/m water area. The eradication of weed and predatory fishes is necessary to avoid competition with culturable fishes for space and food. These fishes may be eradicated either by repeated netting or draining the water or poisoning the pond. Generally used poisons for this purpose are mahua oilcake (200 ppm), 1% tea seedcake or turpentine oil @ 250 1/ha. The other chemicals such as Aldrin (0.2 ppm) and Endrin (0.01 ppm) can also be used. In case of the use of these chemicals, the stocking of fish seed (fry/fingerlings ) may be delayed atleast by 10 to 25 days so as to facilitate elimination of the chemiccals/residues.
Stocking ————————
Judicious selection of compatible fast growing species is of vital importance in maximizing fish production. A combination of three species viz. mirror carp, grass carp and silver carp fulfills the species selection requirements and this model has proven to be the ideal combination for sub-temperate region of the State. Of these, mirror carp is a bottom feeder, grass carp is a macro-vegetation feeder and silver carp is surface feeder.
Species ratio –————————
Selection of species ratio generally depends upon the local conditions, seed availability, nutrient status of pond, etc. The species ratio in the recommended is – 3 mirror carp : 2 grass carp : 1 silver carp.
Stocking details ———————–
Rate of stocking usually depends on the fertility of the pond and the measures adopted to increase its biological productivity by manuring, artificial feeding, monitoring of growth and maintaining good health of fish. The rate of stocking recommended for this zone is 15,000 fingerlings per ha with artificial feeding.It is good to stock the ponds with fingerlings of 40-60 mm size for better survival and high production. It is better to stock the pond after 15 days of manuring in early hours of day or in the evening. The cloudy day or warmer part of day is to be avoided for stocking.
Supplementary feeding ———————-
The level of natural food organisms in the fish culture ponds can not be maintained to the required extent even after manuring. Hence, supple-mentary feeding with diet rich in protein,carbohydrates and fats is essential for higher rate of fish growth. The ingredients generally used for artificial feeding are groundnut oil cake and wheat bran in the ratio of 1:1. Feed should be preferably provided in the form of pellets or bowls @ 2% of the total biomass and feed them by hand at different places in the ponds so that all the fishes must get uniform quantity of feed for their uniform growth.
Grass carps are to be fed with chopped succulent grass or discarded vegetable leaves. Kitchen refuse can also be used as supplementary feed for fish culture.
A practical feed formula which is in practice at Fish Farming is given below:
Ingredients Ingredients Qty for preparing
(%) 10 kg feed
Fish meal 15 1.5 kg
Wheat bran 50 5,0 kg
Groundnut cake 30 3.0 kg
DCP 5 0.5 kg
Supplevit-M 0.5 0.05 kg
Supplementary feeding @ 1-2% is necessary for better yiel per unit area since the natural productivity of water in this zone is very less. The comparative performance of different species under two regimes (with supplementary feeding and without supplementary feeding) are given below :
Name of Growth performance Growth performance of
species of three species three species without
with supplementary supplementary feed (2)
feed at 2% level (g)
Initial Wt. after Gain in Initial Wt. after Gain in
Wt 8 months wt. wt. 8 months wt.
Gross % Gross %
Silver carp 312 16,000 15654 5424 308 12117 11809 5830
Grass carp 927 57,482 56555 6100 1,015 26182 25167 2479
Common carp 6173 39,430 33257 538 1,800 8061 6261 381
Monitoring of growth: ——————-
Besides nutrients, the abiotic factors like temperature, salinity and photoperiod influence the growth of the fish.After 2 months of stocking, the 20% of the stock should be harvested so as to evaluate the growth per month as well as to calculate the correct amount of feed to be supplied daily. Later on, this practice is to be repeated every month till the fish stops artificial feeding. Based on research data, it is seen that the fishes attain
their growth during 8 productive months (i.e. middle of March to middle of November) under the existing climatic conditions. During four winter months (i.e. middle of November to middle of March), there is no growth. As such the supplementary feed is to be given during the eight productive months. The results in terms of production efficiency of aforesaid model is computed as high as 4 tonnes per ha per year.
Harvesting ——————
Harvesting is conveniently done either by drag netting or by cast netting (useful for small ponds) or by draining the pond. Suplementary feeding is stopped a day before the date of harvesting. Harvesting is done during cool morning hours as per the demand of market. For this region, the best time of harvesting is December and January whch are non-produc-
tive months for fish farming. The preferable time of stocking is mid of March or first week of April. In this way the four nonproductive winter months can be utilised for the renovation, desilting and preparation of ponds.
Calender for fish farming –——————-
January:
(i) Construction of tanks.
(ii) Renovation of tank which includes desilting and repairing of old tanks.
February: Preparation of tank.
(i) Liming: General rate 250 kg/ha or 25 g/sq m of water area.
(ii) Manuring: After a week of liming, manuring should be done @ 25 tonnes/ha. Initially half of the total quantity and subsequenlty rest half in equal monthly instalments. For example 1 hactare area (10000 sq. m.) the total amount of manure required is 2500 kg i.e. 1250 kg to be applied in the beginning and rest to be applied @ 156 kg per month from March to October.
(iii) Fill the pond with water just after manuring and leave it for 12-15 days.
(iv) In case of old ponds, the unwanted weed fish, predatory fish and harmful insects etc. to be eradicated either manually or by poisoning the water.
March: Stocking of tanks
(i) Stocking should be done after 15 days of manuring when water colour is green which is indicative of the presence of natural food in water. The cloudy day or warmer part of the day is to be avoided for stocking.
(ii) Species to be stocked are common carp, grass carp and silver carps. (iii) Species ratio- common carp 3:Grass carp 2: and silver carp 1.
(iv) Stocking rate – 15,000 fingerlings/ha. For example 0.1 ha tank is to be stocked with 1500 fingerlings, in the ratio of 750 common carp : 500 grass carp : 250 silver carp.
(v) Stocking upto 15th March.
Feeding
Feed ingredients : Wheat bran (50%) +
groundnut cake (40%)
+ supplevitamins(15%)
or
Wheat bran (50%) +
Groundnut cake 30%)
+ Fish meal (15%) +
Supplevitamins (0.5%)
+ DCP (5%).
Feed requirement : For a water body of 0.1
ha stocked with 1500
fingerlings is 15 kg
BEST MANAGEMENT PRACTICES IN AQUACULTURE
http://www.sac.org.bd/archives/publications/Aquaculture.pdf
