Intensive culture of common carp (Cyprinus carpio). An experimental analysis

Table of contents

ACRONYMS

ABSTRACT

1.1 General introduction
1.2 Objectives
General objective
Specific objectives
1.3 Limitation

2 LITERATURE REVIEW
2.1 Intensive culture
2.2 Global status of aquaculture and common carp
2.3 Habitat and biology
2.4 General morphology
2.5 Water quality parameters
2.6 Nutritional requirement of Common carp
2.7 Feed and feeding behavior
2.8 Water quality management

3 MATERIALS AND METHODS
3.1 LEE site
3.2 Tank preparation
3.3 Procurement and stocking of fingerlings
3.4 Tank management
3.4.1 Feeding
3.4.2 Water quality management and parameter
3.5 Fish sampling
3.6 Fish harvesting and marketing
3.7 Analytical methods
3.7.1 Fish growth parameters
3.7.2 Gross margin calculation
3.7.3 Statistical analysis

4 RESULTS
4.1 Water quality parameters
4.2 Water exchange
4.3 Fish growth and production parameters
4.4 Gross margin analysis

5 DISCUSSION
5.1 Water quality
5.2 Growth and production

6 CONCLUSION

REFERENCES

APPENDICES

ACRONYMS

°C = Degree Celsius

AFU = Agriculture and Forestry University

AM = Anti Meridiem

CP = Crude protein

DAP = Di-Ammonium Phosphate

DO = Dissolved oxygen

DWG = Daily Weight Gain

FAO = Food and Agricultural organization

FAVF = Faculty of Animal Science, Veterinary Science, and Fisheries

FCR = Feed Conversion Rate

g = Gram

ha = Hectare

kg = Kilograms

LEE = Learning for Entrepreneurial Experience

MOC = Mustard Oil Cake

Mt = Metric ton

pH = Pouvoir Hydrogen

PM = Post Meridian

S.D = Standard deviation

TA = Total Alkalinity

ABSTRACT

Intensive culture is a system where fish are culture in a well-managed manner and this system includes small ponds, tanks, and raceways with very high stocking density. In this system, fish is almost completely fed on formulated feed and good management is undertaken for controlling all aspects which require proper growth. Production of common carp is increasing so, intensification of its production from extensive to semi-intensive and intensive aquaculture systems is a new trend. In this study, intensive common carp (Cyprinus carpio) culture was conducted from 2nd October to 28th October in experimental cemented tank of 25 m2 of Fish hatchery complex, AFU to learn to produce common carp through intensive culture. The stocking density was 250 fish at the rate of 10 fish/m2. Average body weight of 27.9±9.8 g fish were stocked in the tank and feeding was done at 3% of body weight. Feed was made from mustard oil cake (70%) and rice bran (30%), a feeding tray having an area of 50x50 cm2 was used for feeding. Sampling was performed at a ten days interval and feeding was adjusted accordingly. The average temperature, DO and pH of the culture tank of 5:30 am and 3pm was 28.7±0.9 and 30.2±1.2°C, 7.1±1.3 and 12.4±1.6 mg/L, 7.7 and 7.8 respectively which were within the suitable range for culturing. After harvesting, the total harvested weight of fish was 12.9 kg while total stocking weight was 7.4 kg. Mean harvest weight of fish was 54.4±28.6 g while mean stocking weight was 27.9±9.8 g. The survival rate of fish was 97.6%. The extrapolated GFY and NFY obtained was 72.6 and 30.8 t/ha/year respectively. The fish were handed over to Aquaculture farm, AFU which they will rear further in tanks and ponds. During culturing water was exchanged daily in the morning for maintaining proper water quality. Thus, the results suggested that common carp intensive farming is feasible in cemented tanks with good survival rate.

1 INTRODUCTION

1.1 General introduction

Nepal lies between India and China, being landlocked, the country is deprived from oceanic sources. About 5% of the total area of the country is occupied by freshwater aquatic habitat which along with fish species can be viewed as prospects for the development of fisheries sector in the country (Gurung, 2003). Fisheries in Nepal has been in practice for a long time but aquaculture is a relatively new practice, which was started in the 1950's. The Nepal Agriculture Perspective Plan (APP) has categorized fisheries and aquaculture in Nepal as a small but important and promising sub-sector of agriculture (Rai, Clausen, & Smith, 2008; Budhathoki & Sapkota, 2018). For poverty reduction the government of Nepal has identified fisheries as one of the prominent subsector. Aquaculture in Nepal was developed after the introduction of common carp and other Chinese carp during the late 30's which was a very important factor for expansion of aquaculture along with seed availability. Aquaculture development project of the government was another major factor which helps in developing infrastructure facilities of government farms along with human resource development and capacity building in 2038-2050 B.S (Shrestha, 2015). The total fish production in Nepal is 91,832 Mt while 70,832 Mt is produced from aquaculture and 21,000 from capture fisheries (CFPCC, 2019).

Fish farming is the process of rearing fish commercially for food purpose and earning money in a tanks or enclosure such as a fish pond and there are three types of fish farming system which are extensive, intensive and semi-intensive (Fish Farming, 2020). Fish farming is commonly described as being extensive, semi-intensive or intensive which generally depends on the level of inputs that feed and stocking density. Development of intensive fish farming system was developed during the 20th century with high input systems and high stocking density (Development of intensive fish farming, 2010). Pond culture involves breeding and rearing of fish in which the entire process required to produce marketable fish is control by human (Fish Culture, 2020). Intensive culture is a system where fish are culture in a well-managed manner and this system includes small ponds, tanks, and raceways with very high stocking density. In this system, fish is almost completely fed on formulated feed and good management is undertaken for controlling all aspects which require for proper growth (Shrestha & Pandit, 2012). In intensive culture, production can be improved from the same pond where extensive or semi-intensive has been practiced previously. Intensive culture has an advantage of less space requirement and control management system, which allows the proper farming condition of fish due to such reason trends in fish culture shifting towards intensive culture (Wedemeyer, 2010).

Common carp is an exotic fish belonging to the order Cypriniformes which was introduced in Nepal in the 1950s and after that introduction of other exotic Chinese carp led to the development of cultured fishery in Nepal (Karki, 2016). In Nepal, common carp was introduced from India and Israel and among many varieties, two varieties are under a culture that Cyprinus carpio var. communis and Cyprinus carpio var. specularis (Shrestha & Pandit, 2012). Common carp culture is mostly polyculture based and the intensive culture of it has been in the practicing stage. Fish demand has been rising so to meet demand, production of fish is needed to be increase that's why the intensive farming systems have been started to gain interest among farmers (Roy, Petrobich, Aleksebich & Latifa, 2018). Production of common carp is increasing in this regard, intensification of its production from extensive to semi-intensive and intensive aquaculture systems regarded as the most appropriate approach for meeting the increasing demand of this species (Rahmana, 2015). It is one of the important species of aquaculture and its production has been increased at an average of 10.4% yearly at a global level from 1985- 2002 (Yaron et al., 2009) and it is 4th major produce species in world aquaculture with production of 4189.5 thousand tonnes in 2018 which shares 7.7 % of total production (FAO, 2020). Intensive farming of common carp is possible as it can tolerate crowded conditions, readily adapt to poor conditions, high growth rate, and acceptability and can easily convert artificial food into flesh (Mohapatra & Patra, 2014). In Nepal intensive farming of common carp is a new practice and has not been extended to a commercial level, only 10% of fish farmers of Nepal have been involved in intensive farming (DoFD, 2014).

The common carp is one of the wide culture fish worldwide and it can tolerate harsh environmental conditions like low dissolved oxygen, the low pH, and readily accept formulated feed and has a high growth rate. As Nepal is rich in natural water resource has great potential for fish farming and intensive culture can be carried out within a small area which is best in context of a landlocked country as many fish farmers have small landholdings. Since, the intensive culture of common carp is in the practicing stage through this study we will be able to know the condition required for successful intensive culture of common carp. In Nepal, most aquaculture activities are done extensively which can be intensified to increase productivity by focusing on strengthening the existing aquaculture practices.

1.2 Objectives

General objective

- The overall objective of LEE is to learn to produce common carp through intensive culture

Specific objectives

- To monitor the water quality parameters of the culture system
- To determine the growth and production of common carp
- To calculate the gross margin
- To learn marketing of intensive common carp culture

1.3 Limitation

Major limitation of this LEE work was lack of time availability which affected the production of market size fish. Uniform sized fish fingerlings were not found. Plant protein source was expensive. Time consuming to exchange water by using electric water pump daily and lack of a properly functioning water pump. Lack of lab materials for performing necessary water quality tests such as TA and dissolved oxygen by Winkler method.

2 LITERATURE REVIEW

2.1 Intensive culture

Carps are mostly cultivated in semi-intensive polyculture systems in different units like ponds, cages, and lake enclosures. Based on the production input level and output level, the aquaculture system has been divided into three types: extensive, semi-intensive, and intensive type (FAO, 2005). Intensive culture has an advantage of high productivity and less space than extensive, but it requires high operating costs and a higher survival rate of fish. Careful management is an essential aspect in order to prevent the disease outbreak due to overcrowding. Intensive culture requires a detailed understanding of fish species physiology (Wedemeyer, 2010). In intensive culture there is control over the fish to be produced, harvesting is simple but has disadvantages of high amount of feed requirement as well as danger of oxygen depletion (Shrestha & Jha, 1993). Stocking density greatly depends on the level of feed input and water quality management. In this system, fish are stocked at a high density of 10-15 fish/m3 and the yield obtained range from 15-100 ton/ha/year (Shrestha & Pandit, 2012). For common carp, tilapia and catfish recommended density is 80 fish/m3. The smallest recommended fingerling size for stocking is 15 g (Introduction to intensive cage culture of warm water fish, 2013). Fingerlings of over 10 cm are considered good for stocking as it will ensure better growth and survivability (Carp culture, 2010). Intensive culture of fish in tank helps to regulate high degree of environmental effects such as water temperature, dissolved oxygen, pH, C02, alkalinity and manage the fish stock. Culturing in tank has an advantage of the uniformity in culture environment and allows a wide range of rotational velocities to optimize the fish health and condition (Roy et al., 2018). Due to the high stocking density of fish, water gets polluted because of the wastes which need to be removed to maintain a good oxygen level. In monoculture stocking density ranges from 1000-20,000 carp/ha and for common carp the most profitable stocking density was 16,000 fish/ha. In Japan, the intensive culture of common carp is highly advanced producing more than 90% of cultured common carp (Kestemont, 1995). Production of one and two-year fish has been approximately 3 t/ha in the period from 2003 until today and during the last couple years it has been increased. For the production of one-year carp fingerlings, fry of 2g and 170g for production of fish for consumption, death rate ranges between 30% and 70 % while producing one month old fish. Density of carp culture mostly depends on the age category of the progeny and the farming system, density of the culture must be 500,000 pcs/ha in order to have 30-day old progeny at between 1.5g and 2.5g (Rajić, Đorđević, & Čanak, 2016).

2.2 Global status of aquaculture and common carp

World aquaculture production in 2018 was 114.5 million tonnes which is the highest production of all time. In the world, the production from capture fisheries in 2018 was 96.4 million tonnes which was an increment of 5.4% from average of previous 3 years. Inland aquaculture production in 2018 was 51.3 million tonnes of aquatic animals contributing 62.5% of the world's farmed food fish. Asia dominated with 89% of total world's aquaculture production of farmed aquatic animals (FAO, 2020).

Common carp was cultured first in Rome taking wild carp (Balon, 1995) and later was introduced in China, Japan, and Greece (Jhingran & Pullin, 1985). Carp culture for food was expanded after the use of fancy carp for beauty purposes (Amano, 1968; 1971). Different authors (Jhingran & Pullin, 1985; Pintér, 1989; Kuznetsov, Aminova & Kuliev, 2011), scientists have identified four subspecies of common carp which are: Cyprinus carpio carpio , Cyprinus carpio aralensis, Cyprinus carpio haematopterus, Cyprinus carpio viridiviolaceus (FAO, 2011). Aquaculture is a relatively new term for Nepal as it was started in the mid-1940s with indigenous major carp on a small scale, later in 1950 common carp was introduced then its breeding succeeded in 1960 followed by monoculture and became popular among farmers (FAO, 2005).

Common carp have been introduced in different countries for cultural purpose and in many places, it has been considered as invasive species yet it is widely cultured freshwater species in the world (Welcomme, 1988; Hasan et al ., 2007; FIGIS, 2011). It has been distributed worldwide and due to its wide environment tolerance, high fecundity and long life make it invasive species and it is called an ecological engineer as it can modify aquatic ecosystem (Qui et al ., 2019). It has the potential for commercial aquaculture in Asian and European countries as it is highly adaptive to both environment and food. Common carp is one of the most cultured freshwater fish in the world and in Nepal also is one of the most cultured fish. According to FAO freshwater fish production was 31,839,573 tonnes in 2005, and in 2011 it increased to 45,335,385 tonnes, common carp contributed 8-9% of total global production and its production in 2018 was 4189.5 thousand tonnes (FAO, 2020). Asia alone contributes 90% of common carp aquaculture production and in Asia common carp is mostly culture semi intensively following the polyculture system (Rahmana, 2015). During the last 2 decades, carp culture has increased at the rate of 12% annually and carp alone contributes 70% of total inland aquaculture production in Asia and the world. Fish demand has been rising so to meet demand production of fish is needed to increase that's why the intensive farming systems have been started to gain interest among farmers (Roy et al., 2018). In Nepal, fish production contributes 4.18 and 1.13% in the AGDP and GDP respectively. The annual per capita consumption of fish in Nepal is 3.11 kg (CFPCC, 2019).

2.3 Habitat and biology

Common carp are mainly found in the temperate region of Asia, mainly in China It is native to Central Asia and is very widely distributed all over the world. It is used in ponds and captive fisheries as it has the potential of growing rapidly in eutrophic waters and the ability to tolerate adverse environmental condition (Cyprinus carpio, 2019). They naturally live in temperate climates in fresh or slightly brackish water with a pH of 6.5–9.0 and salinity up to about 0.5%. It prefers the shallow type of water body having a muddy bottom, it is a bottom dweller fish but search food in middle and upper layer of water (FAO, 2009).

Common carp can grow to size of very large if adequate space and nutrient are available. The daily growth of carp can be 2 to 4 percent of body weight. Carps can reach 0.6 to 1.0 kg body weight within one season in the polyculture fish ponds of subtropical/tropical areas. Growth is much slower in the temperate zone: here the fish reach the 1 to 2 kg body weight after 2 to 4 rearing seasons (FAO, 2009). The growth of scale carp is 1-2 kg in a year while that of mirror carp is 2-3 kg, it is multiple breeders with peak breeding season of March/April in terai and April/May in hills (Shrestha & Pandit, 2012).

2.4 General morphology

Common carp has a flat and deep body, short and small head, protractile mouth, and two pairs of maxillary barbells. Its dorsal fin is long and has a sharp spine at front. Two species of carp are in culture in Nepal that Cyprinus carpio var. communis which body is completely covered with golden scales in a regular manner and Cyprinus carpio var. specularis which body is unevenly covered with few large shiny scales (Shrestha & Pandit, 2012). It has a color of brownish-green on the back and upper side, shading to golden yellow ventrally and fins are dusky with ventrally reddish tinged. (FAO, 2009). The sucker-like mouth to picks up small portions of bottom sediment, filter out the mud and silt, and consume the edible matter (Shrestha, 2008). Common carp has a relatively large mouth that opens in an according to the manner which helps them to digs pond bottom. They have two pairs of barber one at the upper lip and another at the corner which helps them in searching foods and it also consists of 5-5 molar like pharyngeal teeth which is used to grind foods (Froese & Pauly, 2011).

2.5 Water quality parameters

The temperature range of 23-30°C is considered good for the proper growth of common carp while it can occur within a temperature range of 3-35°C (Froese & Pauly, 2011; FAO, 2011) and optimal pH for its growth is around 6.5-9.5. It can survive low dissolved oxygen of 0.3 mg/l as well as supersaturation condition also (FAO, 2009). Common carp are incredibly hardy, capable of surviving in water that is depleted of oxygen (less than 1mg/l), very warm (to 36 0 C), very cold (near freezing), saline (16ppt) and polluted with various wastes (Moyle, 2002).

Goddard (1996) reports the intensive culture water quality such as temperature ranging from 23-25°C is optimum for common carp culture and dissolved oxygen below 0.9 mg/l is lethal for many species. In intensive and semi-intensive system unused feed and other waste product utilize the oxygen for oxidation, produce CO2 which affect culture condition. 2-10 ppm CO2 is consider ideal for good productivity of pond and above 30 ppm it cause depletion of oxygen leading to mortality. pH below 5 affects the appetite of fish and their growth will be restricted and their capacity to tolerate toxic substance will also decrease. Free ammonia NH3 may be harmful to fishes if it is above 0.05 mg/L of water, two forms of ammonia exits in pond that ionized and un-ionized among these un-ionized form is toxic to fish. Total alkalinity of 20 ppm is recommended for intensive culture of catfish and 80-100 ppm for hybrid stripe bass. Hydrogen sulfide of 0.002 mg/l is considered safe for freshwater fish (Datta, 2012). Temperature (20-32°C), pH (8.05-7.21), dissolved oxygen (5.8 mg/L-2 mg/L), total alkalinity (70-130 mg CaCO3/L) and total hardness (64-114 mg CaCO3/L) were observed in intensive culture of carp (Das et al., 2004). In an experiment of influence on stocking density of common carp, the following water quality parameters were monitored:

Table 1. Water quality parameters

Abbildung in dieser Leseprobe nicht enthalten

Source: (Enache, Cristea, Ionescu, & Sandita, 2011)

The average water quality parameters observed during intensive culture period in three different treatment pond were in range of temperature 27.4 ± 0.8, pH value ranged from 6.93 ± 0.36 and 7.33 ± 0.31 and dissolved oxygen were 6.91 ± 0.42 and 7.74 ± 0.55 mg/L (Roy et al., 2018).

2.6 Nutritional requirement of Common carp

The daily requirement of protein for common carp is about 1 g/kg body weight for maintenance and 12 g/kg bodyweight for maximum protein retention. Feed containing 30-38% crude protein will fulfill the need for protein requirements. Lysine requirement at the fingerling stage is about 2.25% of the diet and common carp can utilize lipids and carbohydrates as a dietary energy source so, the supplement of essential fatty acid and carbohydrate in feed ensures the best growth and better feed efficiency. Generally, 30-40% of dietary carbohydrate is considered good for common carp beside these common carp also require several minerals and vitamins in a small amount (FAO, 2020). Carp has a high amount of n-3 as well as n-6 fatty acid while fed on natural feed and has less when fed with supplement feed, high content of n-3 fatty acid in carp can be gain by feeding high energy diet having a high level of fish oil (Steffens & Wirth, 2007). In intensive common carp culture the supplement feed should cover all the nutritional requirements of fish for proper growth and development, usually feed containing 35-55% crude protein with vitamin and mineral ensure the nutrient requirement (FAO, 2010).

2.7 Feed and feeding behavior

Natural feeding

Carp are omnivorous which prefer more animal food like water insects, larvae of insects, worms, mollusks, and zooplankton. It also feeds on stalks, leaves and seeds of aquatic and terrestrial plants, decayed aquatic plants, etc. Carp pond farming is based on the ability of the species to accept and utilize cereals supplied during the culture period. Post larvae feeds on moina, cyclops, nauplii and ceriodaphnia. Fry feeds on diatoms, cyclops, rotifers, diaphanosoma, moina, daphnia, ostracods, and insects including chironomid larvae, euglena, and closterium and changed its diet to consume decayed vegetable matters, mollusks, insects (Jhingran & Pullin, 1985). On the basis of food availability, many fish changes their food selectivity and feeding niche so does common carp (Hegrenes 2001; Iguchi & Abe 2002). Their diet varies depending on what foods are available, but they are known to eat micro crustaceans, aquatic insect larvae, mollusks, swimming and terrestrial insects and seeds and other plant matter (Hume et al ., 1983a; Koehn et al., 2000).

Fertilization of ponds helps in generating natural food and there are wide varieties of fertilizer that can be used. A combination of organic and inorganic can be used, cow dung at the rate of 5000 kg/ha or any other organic fertilizer having the same manure property can be applied. Organic manure is applied at the gap of 3 days from liming and inorganic fertilizer is applied after 15 days of organic manure (FAO, 2010; Intensive fish culture, 2015). Fertilization dose depends on its nutrient availability and nutrient status general recommended dose for nitrogen fertilizer is 0.2-0.4 g N/m2/day and phosphorous fertilizer is 0.1-0.2 g P/m2/day whereas manure of 120-150 kg/ha (Shrestha & Pandit, 2012).

Supplementary feeding

Common carp mostly feed on artificial feed followed by zooplankton and in case of absence of benthic invertebrates then they switch to zooplankton (Rahman et al., 2010). Formulated feed is one of the important aspects and feed containing proper nutrition is needed according to their body weight per day. Feed size has an important role in the growth and feeding efficiency of fish so, feed size should be maintained with respect to mouth size, fish size and weight gain. The optimal feeding frequency for many fish is twice per day and in case of feeding period there have been few studies which suggest it depends on two-factor, water temperature and feed size. Feeding activity fluctuate daily and seasonally with photoperiod. In an intensive culture system there is total dependence on well-balanced nutritionally reached formulated feed and stocking density, it does not limit by the production of natural food instead it depends on the ability of species to tolerate and grow as well as proper maintenance of water quality (Goddard, 1996).

The protein requirement of common carp varies between 35-45% for larvae, between 30% and 40% for saplings, and between 20%-30% for consumption fish in summer II and III (Enache, Cristea, Ionescu, & Sandita, 2011). In an intensive system, supplementary feed is one of the key factor for successful culture and it is the most costly aspect of culture, various studies regarding the replacement of animal protein by plant protein such as soybean in order to reduce the cost of feed. Soybean has been used as a potential protein source to fulfill the requirement of animal protein in feed and it was found that soybean with the supplement of methionine and 5% oil will attain growth as the same of animal protein (Viola, Mokady, Rappaport, & Arieli, 1982). In intensive fish culture non-retained feed protein is a major problem. Feed containing 40% CP recommended for carp feeding later was decreased to 30-35% CP based on practical feeding studies and a feeding rate of 3-4% is required for the optimal growth of carp. Different feed ingredients such as soybean, sunflower seed cake, maize bran, and cottonseed cake and fish meal along with different plant materials can be used for making a feed. Soybean meal however is not considered efficient feedstuff as it is barely digestible by stomach less carp and reduce the energy content of feed. Experiments showed, that a diet of 25% protein, containing 1.7% total lysine was adequate for maximal growth rate and superior with regard to feed costs and pollution. Soybean meals often are not toasted properly and antitrypsin residue hampers the protein digestion of the pepsin-deficient carp, which depends on trypsin (Voila, Lahav, & Angconi, 1992).

Supplement feed on the basis of its protein content and energy has different feed conversion rate like wheat has feed conversion rate of 4-5, soybean 2-3 and fish meal has 2-3. Feeding the same quantity of feed daily in two to three portion helps to obtain better feed conversion rate and the daily requirement of supplement feed changes according to body size (FAO, 2010). The percentage of food consumed in relation to body weight decreases as the fish grow larger and their metabolic demands decrease (Goddard, 1996). Feed conversion obtained with commercial pellets in extensive culture is less than one, 1.2-2.6 in semi-intensive and 1.5-2 in intensive system. Higher feed conversion rate can be obtained by smaller stocking size, higher stocking rate and increasing harvest size (Culture system and practices, 2020). Feed conversion rate of common carp generally varies with age group as shown in table (Woynarovich, Moth-Poulsen, & Peteri 2010):

Table 2. Feed conversion rate

Abbildung in dieser Leseprobe nicht enthalten

In Japan, they applied a special method of using definite quantities and quality of fish food to increase the body weight of fish ten times during the culture period of 210 days. Variety of foods such as raw silkworm pupae, pressed barley and different kinds of freshwater worms were used, during summer when temperature exceed 32°C then carp stopped feeding so they used to feed in every 2 hours during night under electric lamp when temperature falls below 25 or 25°C (Kawamoto, 2011). Feeding behavior of common carp greatly depends on water temperature, when the water temperature is of 18-20°C then common carp feeds actively and when the temperature falls down below 8°C then it stops feeding and when the temperature falls below 5°C then it goes into hibernation (FAO, 2011).

Mohapatra and Patra (2014) studied on the effect of different feed ingredient on growth of common carp using different treatment as shown in table:

Table 3. Composition of different feed ingredients used in different treatment

Abbildung in dieser Leseprobe nicht enthalten

So, fish fed with T1 had weight gain of 0.056 g/day; with T2 had 0.051 g/day, T3 had 0.039 g/day and controlled had 0.47 g/day. The survival rate was 90% when the fish were fed with T3 and 75% with T1. The largest fish fry size obtained was 8.4 g when fed with T1 and the smallest size of fish (6.21g) was obtained when fed withT3. The fish growth was higher when fed higher protein containing feed (35.2%) and lower growth when fed without having fish meal.

Fish (40-50 g) were stocked in three different tank (5-7 m diameter and 1-1.5 depth) that T1, T2 and T3 at stocking density of 50, 50 and 30, supplement feeding were applied 2-3 time a day at 5-7% of body weight. Because of supplement feed availability fish grows faster, common carp attain the maximum average and daily weight gain (3.2 ± 0.1 g) was in the month of December and lowest was (1.92 ± 0.2 g) in the month of August in T3. The specific growth rate of common carp was 1.23 ± 0.64 to 1.33 ± 0.83, 1.27 ± 0.9 to 1.34 ± 0.8 in mirror carp (Roy et al., 2018). Growth parameters of common carp were analyzed by rearing in semi-closed system using 13 plastic tanks. In the study feed was given at 5% of body weight containing 25% CP. Average daily growth rate of 4.87 g/day and average fish weight increments for 13 tanks were 248.2 g. Average specific growth rate was 2.44 %/day and average FCR obtained was 2.12 (Taher & Al-Dubakel, 2018).

In Serbia intensive farming of common carp was done which gave a yield of 3000 kg/ha. The production per unit area in an intensive system was increased by 50% and fish were completely fed on extruded feed (Rajic, Đorđević, & Čanak, 2016). In Slovenia, Common carp intensive farming was done in the earthen pond where stocking density was 3000-7000 fish/ha (average body weight 50-300 g) during March and another stocking was done on June at the rate of 10000-70000 fish/ha (average body weight 1 g) which was fed with 31% crude protein floating fed at the rate of 3% of body weight and regular aeration was done and production achieved was 5-10 t/ha/yr (Gospic, 2009). In Japan intensive culture of common carp was done using net cage (25-100m2 and 1.5m depth) stocked with yearlings of 100-200 gram at the rate of 75 fish/m2 which produced 1 kg of fish during 6 month of culture fed with 39% protein content feed, containing cutlet oil and silkworm pupae (Kestemont, 1995). Production of intensive common carp in different countries are given in below table:

Table 4. Production of common carp in different countries

Abbildung in dieser Leseprobe nicht enthalten

Source: (Shrestha & Jha, 1993)

2.8 Water quality management

For maintaining proper water quality conditions one of the important thing is to do aeration. Aeration is important in an intensive pond as it has high density of fish and it can be done mechanically to increase the dissolved water concentration in water by paddle aerator, aspirator aerator and submersible aerator (Carp culture, 2010). Paddle wheel aerator can rise dissolved oxygen level from 0.05 to 4.9 mg/l within 4 hours in 0.5 ha pond (Datta, 2012). Water quality in intensive ponds depends on volume of water entering, biological process within pond and water leaving the pond. Aeration by pure oxygen increased oxygen concentration, improved nitrification and reduced organic load compared to paddle aerator. Intensive pond size of 25 m3 having stocking density of 70-300 fish/m3 (100-300 gram) the water exchange rate was 4 times/day with draining frequency of 2 times/day (Milstein, Zoran, Kochba, & Avnimelech, 2001). Carp are intensively cultured in Israel in reservoir (0.1ha) with application of strong aeration facility and water is usually replaced 5 times a day. And the average output was 25 kg/m3 using 30% crude protein feed (Kestemont, 1995). Water exchange rate differ with production period, stocking density, total biomass, natural productivity, turbidity, source and volume of water. During first month of culture low level of water exchange should be followed rather than heavy exchange of water in order to eliminate the problem of seepage and evaporation, lowering water level first and addition of water especially during day time is not recommended as it will increase the water temperature which affects oxygen holding capacity of water and hasten the degradation of pond bottom (Datta, 2012). Water quality can be degraded by feed also so good quality pellets and especially extruded feed can minimize the water pollution and disease occurring chances because of high digestibility. For analysis of water quality of ponds besides chemical methods phytoplankton and zooplankton can be used as bio-indicator. Using biological methods of water assessment has an advantage over chemical analysis as they can reflect overall ecological quality, integrate variations in the environment and indicate biologically available nutrients (Dulic, Ciric, Relic, & Simic, 2010).

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