Effect on Water Quality, Pond Productivity and Growth of Carps in Polyculture System by Using Homestead Organic Wastage as a Pond Manure

Sustainable aquaculture depends upon eco-friendly and economically and socially viable culture system. The recycling of organic wastes for fish culture serves the dual purpose of cleaning the environment (by avoiding the problem of waste disposal) and providing economic benefit. The recycling of animal dung/wastes in fishponds for natural fish production is important to sustainable aquaculture and to reduce expenditure on costly feeds and fertilizers which form more than 50%of the total input cost. However, the indiscriminate use of these manures in fishpond, instead of improving the pond productivity, may also lead to pollution. Therefore, it is necessary to know the standard dose of these wastes, which would keep the physico- chemical parameters of pond water in a favorable range required for the survival and growth of fish. Although a lot of work has been done on the utilization in fish culture ponds, of animal manures, particularly farmyard manure, poultry droppings, cow dung and biogas slurry which are suitable substitutes for costly feeds and fertilizers (Schroeder 1980; Dhawan and Toor 1989), there are few reports on the recycling of Homestead Organic Wastage (Sharma 1988) in fish ponds. Therefore, the present study was conducted to work out the effect of Homestead Organic Wastage as pond manure on physico- chemical and on the growth of carps (Indian major carps and exotic carps) in the polyculture system. 

The present study was conducted at the fish farm of Islam Fish Farm, Gazirhat, Debhata, Satkhira and Khulna University Laboratory during September 2002 to August 2003 (300 days).

Preparation of tanks: Experiments were conducted in concrete tanks of 20m² with a depth of 1 m a thin bottom of all tanks. Subsequently all the tanks were filled with tube well water.

Manuring of tanks: The Homestead Organic Wastage was used as manure at 20 (Pm²0) and 40 (PM40) t/ha/year i.e. 34.5 and 69.0 g/m²/week respectively, during the course of the experiment. No supplementary feeding was given to fish in the two treatments. In Control treatment (C) no manure was added and fish were fed with supplementary feed containing 50% deoiled rice bran and 50% deoiled mustard oil cake at 2% of fish biomass. Both manured and Control group were replicated there times.

Stocking of fish: Each tank was stocked with fry (2 fish/ m²) of different fish species namely 8 Catla (Catla catla), 10 Rohu (Labeo rohita), 8 Mrigal (Cirrhinus cirrhosus), 8 Common carp (Cyprinus carpio) and 6 grass carp (Ctenopyaryngodon idellus) in May 2003. Mean total weight of the fishes at the time of stocking was 3.0 - 5.0 gm for Catla; 5.0 - 12.0 gm for Ruhu; 2.0 – 2.7 gm for Common carp; 2.2 - 2.7 gm for Grass carp and 2.5 - . 3.0 gm for Mrigal

Observations recorded: The water from all tanks was analyzed at monthly intervals (between 7-8 a.m.) for physico- chemical parameters: temperature, pH, free carbon dioxide, phenolphthalein alkalinity, methylorange alkalinity and total alkalinity according to APHA (1991), water soluble phosphates according to Jackson (1967) and nitrate-nitrogen according to Keeney and Nelson (1982). Qualitative and quantitative analyses of phytoplankton and zooplankton were also done at monthly intervals, following the methods of Vollenweider (1971) and APHA (1991). Fish sampling was done at monthly intervals, growth of fish was recorded and Total Weight gain (TWG) and Specific Growth Rate (SGR) was estimated: 

During the 270 days of culture, water temperature ranged from 12 – 35 C, with the maximum mean temperature in Control treatments followed by Pm²0 and PM40 (Table 1), pH varied from 8.03 - 9.24, with the highest mean pH in Control and Pm²0 followed by PM40, dissolved oxygen ranged from 6.25 - 14.00 mg/l, the highest mean DO in Pm²0 followed by PM40 and Control. 

Table 1.Changes in physico-chrmical parameters of water in different treatments.

Free carbon dioxide ranged from 0 - 164 mg/l, with a maximum mean level in Control followed by PM40 and Pm²0, phenolphthalein alkalinity varied from 0 – 120 mg/l with a maximum mean in Pm²0 followed by Control and PM40, methyl-orange alkalinity varied from 100 – 268 mg/l, the maximum mean value in Control followed by Pm²0 and PM40 and total alkalinity ranged from 140 - 350 mg/l with the highest mean alkalinity in Control followed by Pm²0 and PM40. Nitrate nitrogen varied from 0.44 - 2.45 mg/l, with the highest mean level in Control followed by PM40 and Pm²0. The difference in the above physico-chemical parameters between manured groups and Control were not significant. The water- soluble phosphates varied from 0.07 - 9.38 mg/l, highest mean levels being in PM40 followed by Control Pm²0 and the differences were significant (PM40>C=Pm²0) (Table 1).

Total phytoplankton varied from 4.89 - 89.82 x 10⁶/l, the highest mean levels in PM40 followed by Pm²0 and Control and the differences were significant. Cynophyceae ranged from 1.15 - 67.29 x 10⁶/l, with maximum mean levels recorded in PM40 followed by Pm²0 and Control and the differences were significant between treatments, Chlorophyceae varied from 0.75 - 24.59 x 10⁶/l, with highest mean levels in Pm²0 followed by Control and PM40 and the differences were not significant and Baccillariophyceae varied from 0 - 0.72 x 10⁶/l, with highest mean levels recorded in Control followed by Pm²0 and PM40 and the differences were significant (Table 2).

Total zooplankton varied from 490.69 - 2448.84/l, with maximum mean levels in PM40 followed by Pm²0 and Control and the differences between the treatments were significant. Copepoda varied from 58.44 - 1053.43/l, with maximum mean levels in PM40 followed by Pm²0 and Control and the differences between treatments were significant; Cladocera varied form 51.56 - 698.87/l, with maximum mean levels in Pm²0 followed by PM40 and contrail and the differences were significant; Rotifera varied from 200.68 - 1006.04/l, the maximum mean levels being in PM40 followed by Pm²0 and Control and the differences were significant (Table 2). 

Table 2: Changes in biological parameters of water in different treatments.

Percent Total Weight Gain and Specific Growth Rate, in C. catla was highest in PM40 followed by Pm²0 and Control and the differences were significant; L. rohita had higher growth in Pm²0 followed by PM40 and Control and the differences were significant; C. cirrhosus had maximum growth in Control followed by Pm²0 and PM40 and the differences were significant; C. carpio had maximum growth in Control followed by Pm²0 and PM40 and the differences were significant. In the case of C. idellus, maximum growth was in Control followed by PM40 and Pm²0 and the differences were significant (Table 3). 

Table 3: Growth of different fish species in different treatments.

Physico-chemical parameters of water play a significant role in the biology and physiology of fish. In the present study the physico-chemical parameters of water in different manured and Control groups remained within the favorable range required for carps (Jhingran 1991). Water temperature, pH, dissolved oxygen, free Carbon Dioxide and Alkalinity (phenol-phthalein, Methyl - Orange and total) did not differ significantly between different treatments. This suggests that Homestead Organic Wastage even at a higher dose (40t/ha/year) did not have any adverse effect on the Physico-chemical parameters of water. Sharma and Das (1988) reported that even heavy organic loading through Organic Waste did not reduce the dissolved oxygen content of water. The nitrate –nitrogen content of water did not differ significantly between different treatments; however, the water-soluble phosphates were significantly higher in PM40 than Pm²0 and Controls. This may be attributed to the presence of phosphorus in Homestead Organic Wastage. Sharma (1988) also recorded higher levels of phytoplankton in ponds receiving Homestead Organic Wastage.

The biological productivity of any aquatic body is generally judged through the qualitative and quantitative estimation of plankton, which form the natural food of fish (Ahmed and Singh 1989). Animal wastes lead to increased biological productivity of ponds through various pathways, which result in increase in fish production. In the present study, the biological parameters of water total phytoplankton and its subgroups Cyanophyceae and Chlorophyceae (excluding Bacillariophyceae which was significantly lower in manured ponds) and total zooplankton were significantly higher in ponds receiving Homestead Organic Wastage than in Control ponds. This may be due to high level of water-soluble phosphates in the Homestead Organic Wastage. However, no significant difference was recorded in the pond productivity between the two doses of Homestead Organic Wastage used. A uniform production of plankton has also been reported in ponds with recycled Homestead Organic Wastage (Govind et.al.1978; Sharma and Das 1988). Singh 1996 also reported that pond productivity could be maintained for longer periods through the use of pig manure in comparison to cattle dung. Homestead Organic Wastage provides plankton with an additional food source from the bacteria, which thrive on the added organic fertilizer. The nature of the manure also affects the community structure of plankton. In the present study, among phytoplankton, Cyanophyceae was the dominant group followed by Chlorophyceae, where as Bacillariophyceae was poorly represented; among zooplankton, Rotifera was the dominant group followed by Copepoda and Cladocera in all the treatments including Controls.

The growth (weight gain) of the different fish species cultured revealed that in C. catla and L. rohita, TWG and SGR were significantly more in Controls, where as in C. cirrhosus and C. carpio, TWG and SGR were significantly more in Controls and Pm²0 than PM40. Higher growth of these carps in manured ponds may be due to higher availability of natural food in these treatments. Moreover, some carps even feed upon the undigested fraction of these manures directly, which may be low in nutrient value but the microorganism adhering to them are of high protein value (Schroeder 1980). Further, direct feeding upon Homestead Organic Wastage may be more beneficial for the growth of carps since more than 70% of the food of pigs remains undigested and rich in nutrients (Sharma 1989). However, Homestead Organic Wastage at both the levels used in the present study did not have a positive effect on the growth of C. idellus, which was to be expected, C. idellus being a herbivore.

The above study reveals that Homestead Organic Wastage even at higher doses (PM40 t/ha/year) did not adversely affect the physioco-chemical parameters of water. The pond productivity was significantly higher in manured ponds than Control ponds. The growth of C. catla and L. rohita in manured ponds was better than in Control ponds and the growth of C. cirrhosus and C. carpio in Pm²0 was equivalent to Controls. This clearly indicates that carps can be cultured well in ponds receiving Homestead Organic Wastage at 18 t/ha/year, without supplementary feeding. 

Ahmed, S.H. and A.K Singh. 1989. Correlation between antibiotic factors of water and zooplanktonic communities of a tank in Patna, Bihar, p.119-121. In Prod. Nat. Sem. On forty years of freshwater Aquaculture in India, 7-9 November 1989, Central Institute of Freshwater Aquaculture, Bhubneshwar.

APHA 1991. Standard methods for the examination of water and waste water. American Public Health Association, Washington, 1193 p.

Dhawan, A. and H. S. Toor. 1989. Impact of organic manure and supplementary diet on plankton production and fish growth and fecundity of an Indian major carp, Cirrhina mrigala (Ham)in fish ponds. Biopl. Waste 29:289.

Govinnd B.V.,K.V. Raja Gopal and G.S. Singh. 1978. Studies on the comparative efficacy of organic manures as fish feed producers. J. Inland Fish . Soc. India 10:101-10⁶.

Jackson, M.L.1967. Soil Chemical Analysis. Prentice Hall of India, Private United New Delhi.

Jhingran, V.G. 1991. Fish and Fisheries of India. Hindustan Publishing Corporation, Delhi, 727p.

Keency. D. R. and D. W. Nelson. 1982. Nitrogen- Inorganic forms, p643-698. In A. L. page R. H. Miller and D. R. KJeeney (eds).Methods of soil analysis. Part 11. American society of Agronomy Inc. and Soil Science Society of American Inc. Madison, U.S.A.

Schroeder, G.L.1980. Fish farming in manure loaded ponds, p 73-86. In ICLARM-SEARCA Conf. Agri. Aquac. Farm. System, Manila, Philippines,

Sharma, B.K. 1988. Carp farming integrated with various of livestock farming. I.. Fish-cum-pig, 11Fish- duck, 111 Fish- cup- poultry, 1111. Fish-cum-cattle, Compendium of Lecture No. 2 of Training programmed on Integrated Fish Farming, 12-31 January 1989, CIFA (CIAR), Bhubneshwar.

Sharma, B.K. and M.K.Das.1988. Studies on integrated fish-livestock carp farming system. Fishing Chimes 7:15- 27

Singh A.k.1996. Investigation on the effect of pig manure on growth and survivability of Indian major carps and exotic carps spawn in nursery ponds, p. 134. In The Fourth Indian Fisheries Forum, 240-28 November 1996, Uni. Science. & Echelon., Cochin..

Vollenweider, R.A. 1971. A Manual of Methods for Measuring Primary Production in Aquatic Environment. IBP Handbook No. 12.