Fish farming
Fish farming or pisciculture is the principal form of aquaculture, while other methods may fall under mariculture. Fish farming involves raising fish commercially in tanks or enclosures, usually for food. A facility that releases juvenile fish into the wild for recreational fishing or to supplement a species' natural numbers is generally referred to as a fish hatchery. Worldwide, the most important fish species used in fish farming are carp, salmon, tilapia and catfish.[1][2]
There is an increasing demand for fish and fish protein, which has resulted in widespread overfishing in wild fisheries, China holding 62 percent of the world's fish farming practice.[3] Fish farming offers fish marketers another source. However, farming carnivorous fish, such as salmon, does not always reduce pressure on wild fisheries, since carnivorous farmed fish are usually fed fishmeal and fish oil extracted from wild forage fish. The global returns for fish farming recorded by the FAO in 2008 totalled 33.8 million tonnes worth about $US 60 billion.[4] In 2005, aquaculture represented 40% of the 157.5 million tons of seafood that was produced, meaning that it has become a critical part of our world's food source even though the industry is still technically in its 'infancy' and didn't really become well known until the 1970s. Because of this rise in aquaculture, there has been a rise in the per capita availability of seafood globally within the last few decades.[5]

Major categories of fish aquaculture
There are two kinds of aquaculture: extensive aquaculture based on local photosynthetical production and intensive aquaculture, in which the fish are fed with external food supply.
Extensive aquaculture
Aqua-Boy, a Norwegian live fish carrier used to service the Marine Harvest fish farms on the West coast of Scotland
Limiting for growth here is the available food supply by natural sources, commonly zooplankton feeding on pelagic algae or benthic animals, such as crustaceans and mollusks. Tilapia species filter feed directly on phytoplankton, which makes higher production possible. The photosynthetic production can be increased by fertilizing the pond water with artificial fertilizer mixtures, such as potash, phosphorus, nitrogen and micro-elements. Because most fish are carnivorous, they occupy a higher place in the trophic chain and therefore only a tiny fraction of primary photosynthetic production (typically 1%) will be converted into harvest-able fish.
Another issue is the risk of algal blooms. When temperatures, nutrient supply and available sunlight are optimal for algal growth, algae multiply their biomass at an exponential rate, eventually leading to an exhaustion of available nutrients and a subsequent die-off. The decaying algal biomass will deplete the oxygen in the pond water because it blocks out the sun and pollutes it with organic and inorganic solutes (such as ammonium ions), which can (and frequently do) lead to massive loss of fish.
An alternate option is to use a wetland system such as that of Veta La Palma.
In order to tap all available food sources in the pond, the aquaculturist will choose fish species which occupy different places in the pond ecosystem, e.g., a filter algae feeder such as tilapia, a benthic feeder such as carp or catfish and a zooplankton feeder (various carps) or submerged weeds feeder such as grass carp.
Despite these limitations significant fish farming industries use these methods. In the Czech Republic thousands of natural and semi-natural ponds are harvested each year for trout and carp. The large ponds around Trebon were built from around 1650 and are still in use.
In these kinds of systems fish production per unit of surface can be increased at will, as long as sufficient oxygen, fresh water and food are provided. Because of the requirement of sufficient fresh water, a massive water purification system must be integrated in the fish farm. One way to achieve this is to combine hydroponic horticulture and water treatment, see below. The exception to this rule are cages which are placed in a river or sea, which supplements the fish crop with sufficient oxygenated water. Some environmentalists object to this practice.
Very high intensity recycle aquaculture systems (RAS), where there is control over all the production parameters, are being used for high value species. By recycling the water, very little water is used per unit of production. However, the process does have high capital and operating costs. The higher cost structures mean that RAS is only economical for high value products like broodstock for egg production, fingerlings for net pen aquaculture operations, sturgeon production, research animals and some special niche markets like live fish.[9][10]
Raising ornamental cold water fish (goldfish or koi), although theoretically much more profitable due to the higher income per weight of fish produced, has never been successfully carried out until very recently. The increased incidences of dangerous viral diseases of koi Carp, together with the high value of the fish has led to initiatives in closed system koi breeding and growing in a number of countries. Today there are a few commercially successful intensive koi growing facilities in the UK, Germany and Israel.
Some producers have adapted their intensive systems in an effort to provide consumers with fish that do not carry dormant forms of viruses and diseases.
Specific types of fish farms
Within intensive and extensive aquaculture methods, there are numerous specific types of fish farms; each has benefits and applications unique to its design.
Pinjra system

Giant gourami is often raised in cages in central Thailand
Fish cages are placed in lakes, bayous, ponds, rivers or oceans to contain and protect fish until they can be harvested.[2] The method is also called "off-shore cultivation[11] " when the cages are placed in the sea. They can be constructed of a wide variety of components. Fish are stocked in cages, artificially fed, and harvested when they reach market size. A few advantages of fish farming with cages are that many types of waters can be used (rivers, lakes, filled quarries, etc.), many types of fish can be raised, and fish farming can co-exist with sport fishing and other water uses.[2] Cage farming of fishes in open seas is also gaining popularity. Concerns of disease, poaching, poor water quality, etc., lead some to believe that in general, pond systems are easier to manage and simpler to start. Also, past occurrences of cage-failures leading to escapes, have raised concern regarding the culture of non-native fish species in dam or open-water cages. Even though the cage-industry has made numerous technological advances in cage construction in recent years, storms will always make the concern for escapes valid.[2]
Main article: Copper alloys in aquaculture
Recently, copper alloys have become important netting materials in aquaculture. Copper alloys are antimicrobial, that is, they destroy bacteria, viruses, fungi, algae, and other microbes. In the marine environment, the antimicrobial/algaecidal properties of copper alloys prevent biofouling, which can briefly be described as the undesirable accumulation, adhesion, and growth of microorganisms, plants, algae, tube worms, barnacles, mollusks, and other organisms.
The resistance of organism growth on copper alloy nets also provides a cleaner and healthier environment for farmed fish to grow and thrive. Traditional netting involves regular and labor-intensive cleaning. In addition to its antifouling benefits, copper netting has strong structural and corrosion-resistant properties in marine environments.
Copper-zinc brass alloys are currently (2011) being deployed in commercial-scale aquaculture operations in Asia, South America and the USA (Hawaii). Extensive research, including demonstrations and trials, are currently being implemented on two other copper alloys: copper-nickel and copper-silicon. Each of these alloy types has an inherent ability to reduce biofouling, cage waste, disease, and the need for antibiotics while simultaneously maintaining water circulation and oxygen requirements. Other types of copper alloys are also being considered for research and development in aquaculture operations. quantities. Integrated recycling systems
Main article: Aquaponics
One of the largest problems with freshwater pisciculture is that it can use a million gallons of water per acre (about 1 m³ of water per m²) each year. Extended water purification systems allow for the reuse (recycling) of local water.
The largest-scale pure fish farms use a system derived (admittedly much refined) from the New Alchemy Institute in the 1970s. Basically, large plastic fish tanks are placed in a greenhouse. A hydroponic bed is placed near, above or between them. When tilapia are raised in the tanks, they are able to eat algae, which naturally grow in the tanks when the tanks are properly fertilized.
The tank water is slowly circulated to the hydroponic beds where the tilapia waste feeds commercial plant crops. Carefully cultured microorganisms in the hydroponic bed convert ammonia to nitrates, and the plants are fertilized by the nitrates and phosphates. Other wastes are strained out by the hydroponic media, which doubles as an aerated pebble-bed filter.
This system, properly tuned, produces more edible protein per unit area than any other. A wide variety of plants can grow well in the hydroponic beds. Most growers concentrate on herbs (e.g. parsley and basil), which command premium prices in small quantities all year long. The most common customers are restaurant wholesalers.
Since the system lives in a greenhouse, it adapts to almost all temperate climates, and may also adapt to tropical climates. The main environmental impact is discharge of water that must be salted to maintain the fishes' electrolyte balance. Current growers use a variety of proprietary tricks to keep fish healthy, reducing their expenses for salt and waste water discharge permits. Some veterinary authorities speculate that ultraviolet ozone disinfectant systems (widely used for ornamental fish) may play a prominent part in keeping the Tilapia healthy with recirculated water.
A number of large, well-capitalized ventures in this area have failed. Managing both the biology and markets is complicated. One future development is the combination of Integrated Recycling systems with Urban Farming as tried in Sweden by the Greenfish initiative.[14][15]
Classic fry farming
This is also called a "Flow through system" [16] Trout and other sport fish are often raised from eggs to fry or fingerlings and then trucked to streams and released. Normally, the fry are raised in long, shallow concrete tanks, fed with fresh stream water. The fry receive commercial fish food in pellets. While not as efficient as the New Alchemists' method, it is also far simpler, and has been used for many years to stock streams with sport fish. European eel (Anguilla anguilla) aquaculturalists procure a limited supply of glass eels, juvenile stages of the European eel which swim north from the Sargasso Sea breeding grounds, for their farms. The European eel is threatened with extinction because of the excessive catch of glass eels by Spanish fishermen and overfishing of adult eels in, e.g., the Dutch IJsselmeer, Netherlands. As per 2005, no one has managed to breed the European eel in captivity.
Indoor fish farming
An alternative to outdoor open ocean cage aquaculture, is through the use of a recirculation aquaculture system (RAS). A RAS is a series of culture tanks and filters where water is continuously recycled and monitored to keep optimal conditions year round. To prevent the deterioration of water quality, the water is treated mechanically through the removal of particulate matter and biologically through the conversion of harmful accumulated chemicals into nontoxic ones.
Other treatments such as UV sterilization, ozonation, and oxygen injection are also used to maintain optimal water quality. Through this system, many of the environmental drawbacks of aquaculture are minimized including escaped fish, water usage, and the introduction of pollutants. The practices also increased feed-use efficiency growth by providing optimum water quality (Timmons et al., 2002; Piedrahita, 2003).
One of the drawbacks to recirculation aquaculture systems is water exchange. However, the rate of water exchange can be reduced through aquaponics, such as the incorporation of hydroponically grown plants (Corpron and Armstrong, 1983) and denitrification (Klas et al., 2006). Both methods reduce the amount of nitrate in the water, and can potentially eliminate the need for water exchanges, closing the aquaculture system from the environment. The amount of interaction between the aquaculture system and the environment can be measured through the cumulative feed burden (CFB kg/M3), which measures the amount of feed that goes into the RAS relative to the amount of water and waste discharged.
From 2011, a team from the University of Waterloo led by Tahbit Chowdhury and Gordon Graff examined vertical RAS aquaculture designs aimed at producing protein-rich fish species.[44][45] However, because of its high capital and operating costs, RAS has generally been restricted to practices such as broodstock maturation, larval rearing, fingerling production, research animal production, SPF (specific pathogen free) animal production, and caviar and ornamental fish production. As such, research and design work by Chowdhury and Graff remains difficult to implement. Although the use of RAS for other species is considered by many aquaculturalists to be currently impractical, there has been some limited successful implementation of this with high value product such as barramundi, sturgeon and live tilapia in the US[46] eels and catfish in the Netherlands, trout in Denmark[47] and salmon is planned in Scotland[48] and Canada.[49]
More humane methods
Proper stunning renders the fish unconscious immediately and for a sufficient period of time such that the fish is killed in the slaughter process (e.g. through exsanguination) without regaining consciousness. * Percussive stunning. This involves rendering the fish unconscious with a blow on the head. * Electric stunning. This can be humane when a proper current is made to flow through the fish brain for a sufficient period of time. Electric stunning can be applied after the fish has been taken out of the water (dry stunning) or while the fish is still in the water. The latter generally requires a much higher current and may lead to operator safety issues. An advantage could be that in-water stunning allows fish to be rendered unconscious without stressful handling or displacement.[57] However, improper stunning may not induce insensibility long enough to prevent the fish from enduring exsanguination while conscious.[52] It's unknown whether the optimal stunning parameters that researchers have determined in studies are used by the industry in practice.[57] * Fish Farming * Importance: Fish is one of the favorite item in the food menu of almost 60% of Indians.So market * demand is always high for fish items.If we consider the global demand also,the total * requirement becomes very high.The main source of fish is from the sea.but the global fish * harvest from the sea is decreasing rapidly. * The only way we can ensure availability of fish to meet increasing demand is through fish * farming.Inland freshwater fish farming plays major role here.We have large number of natural * ponds here.With a good business plan and decision,we can convert this opportunity to a * successful small scale farm. * Advantages of Fish Farming: * Setting up commercial fish farming business has many advantages. The main advantages of * setting up commercial fish farming business in India are listed below. * setting up commercial fish farming business in India are listed below. * (http://agrifarming.in/wpcontent/ * uploads/2015/02/291.jpg) * Fish Farming * 1. Fish and fish products has a huge demand in India. Fish is one of the most common and * favorite item in the food menu of more than 60 percent of Indian people. * 2. Market demand and price is always high for fish and fish related products in India. * 3. Indian climate is very suitable for fish production and fish farming business. * 4. Various types of easily found water sources are available. You can fill your pond with water * from your nearest river, lake or any other water sources. * 5. Various types of fast growing fish species are available. Farming those fast growing fish * species ensure rapid returns of your investment. * 6. Easily available and low cost labor. You can also start integrated fish farming business with * various types of animals, birds, crops and vegetables (http://agrifarming.in/tag/vegetables). * Integrated fish farming reduces feeding costs and ensure maximum production. * 7. Fish farming in India (http://agrifarming.in/tag/fish-farming-in-india) is really very profitable * and risk less business. Commercial fish farming can create new income and employment * opportunities. Unemployed educated young people can start fish farming business. This will * provide them both financial freedom and permanent income opportunities. * 8. People with other occupation or job can also start fish farming business without impacting * their regular work. If you have suitable land and facilities for fish farming then you can easily * start doing this business. * 9. If you want, you can also apply for bank loan. And there are more benefits of starting fish * farming in India.if you have suitable land and proper facilities don’t misuse the possibilities. * Start raising some fish. If you are new then start small scale farming and gather experience. * You can also visit some fish farms practically to have some knowledge. * Starting Fish Farming: * Starting fish farming in India is not so easy. For setting up profitable fish farming business, you * have to go through some procedures. I have shortly described various steps of fish farming in * India. * How to Prepare Fish Pond: * The most important infrastructure of fish farming business is a pond. We can’t do commercial * fish farming business without a pond. You can use your existing pond or construct a new one for * fish farming in India. We can raise fish in both seasonal and permanent pond. In case of fish * farming in seasonal pond where water will not exist for whole year, we have to raise some fast * growing and quick maturing fish breeds (http://agrifarming.in/tag/fish-breeds). Before stocking * minnow in the pond prepare it properly. Clean the bottom of the pond perfectly and then fertilize * it. Optimize the PH value of pond water and soil. High quality pond environment ensure high * production and profit (http://agrifarming.in/tag/profit). See full pond management system. * Selection of Fish Breeds (http://agrifarming.in/tag/fish-breeds): * Selection of Fish breeds plays major role in the sustainability of our business.The decision * should be based on market demand,maintenance point of view,availability of resource,effective * utilization of resources etc.Carp items such as catla,Rohu,Grass carp,common carp etc are * suitable for Indian ponds.Other breeds such as Tilapia,cat fish etc also cultivated in Indian * Ponds.Polyculture (growing two or more fish breeds in same pond) is the suitable strategy for * optimum utilization of resources.You can get quality fish seeds(baby fishes) from nearest fish * optimum utilization of resources.You can get quality fish seeds(baby fishes) from nearest fish * farmer or from fisheries department. * Fish Feeding and Maintenance: * Special care must be taken while growing fishes.The water PH value must be 7 to 8 for optimum * growth.Chances of virus attacks must be avoided.The pond should be protected from * predators.Daily scouting should be done and suspected fishes should the isolated from pond to * avoid spreading of diseases all over the pond.Diseases can be treated by treating water using * salt, potassium permanganate solution,chemicals etc.It is better to prevent diseases than curing * it. * Marketing: * (http://agrifarming.in/wpcontent/ * uploads/2015/02/dsc04090.jpg) * Fish Farming * Local market is the easily available market for majority of farmers.But the profit will be less * compared to exporting.Fish meat can be processed to produce value added products and the can * be exported to foreign markets.formation of farmers association can help for this marketing.The * advantage of local market is that,the selling of fish is not a problem here and farmers can get a * decent income.So strength of both markets ensures the success of this farming.Fish farming is * becoming one of the main farm field which reduce the unemployment issue in village areas.So * opportunity always exists here for those who love fish farming.

Freshwater Fish Farming- Small Scale * * India is a large producer of inland fish, ranking next only to Japan. * With an abundance of freshwater resources, India has still not been able to tap even 30% of the potential area for inland fish production. Many entrepreneurs have, however, chosen to take this occupation on commercial scale. This is best manifested in Andhra Pradesh, which with 10,56,000 tons of inland fish production in 2007-08 ranked next only to West Bengal, which is far more endowed with water resources. Andhra Pradesh has emerged among the ranks encouraging farmers to form cooperatives to take up farming in ponds around Kolleru lake. * Both the central and state governments have come up with schemes to help the cause of the farmers. | * * Fish culture in ponds
Out of the total inland fish production of over 3.6 million metric tons, more than 60% is contributed by fish culture in ponds and reservoirs. The average productivity from ponds on the national level is around 2,500 kg/ha/year, though in Andhra Pradesh and Haryana it is more than 5,000 kg/ha/year, while in some other states like Bihar and UP it is anywhere between 1,500 and 2,500 kg/ha/year. Fish culture is adopted by all kinds of farmers – small and marginal ones, relatively larger farmers and those who do it on commercial scale. Sizes of ponds also depend on how affluent the farmers are. Ponds less than 100 square meters in area prove unsustainable, while those above 1 hectare are expensive for small players. Many farmers in Tamil Nadu, for instance, use ponds of sizes 30 feet by 30 feet to make their living. On the other hand, a water spread of anything less than 10 hectares in Andhra Pradesh is treated as a pond * Composite Fish Culture- Large Scale | | Introduction :
Fish is the cheapest and most easily digestible animal protein and was obtained from natural sources from time immemorial for consumption by human beings. However, due to over exploitation and pollution, the availability of fish in natural waters have declined considerably forcing scientists to adopt various methods to increase its production. Fish farming in controlled or under artificial conditions has become the easier way of increasing the fish production and its availability for consumption. Farmers can easily take up fish culture in village ponds, tanks or any new water body and can improve their financial position substantially. It also creates gainful employment for skilled and unskilled youths. The technology developed for fish culture in which more than one type of compatible fishes are cultured simultaneous is the most advanced and popular in the country. This technology is known as Composite Fish Culture. This technology enables to get maximum fish production from a pond or a tank through utilization of available fish food organisms in all the natural niches, supplemented by artificial feeding. Any perennial fresh water pond/tank retaining water depth of 2 metres can be used for fish culture purpose. However, the minimum level should not fall below one metre. Even seasonal ponds can also be utilised for short duration fish culture. | | 1. Selection of Pond:
The main criteria to be kept in mind while selecting the pond is that the soil should be water retentive, adequate supply of water is assured and that the pond is not in a flood prone area. Derelict, semi derelict or swampy ponds can be renovated for fish culture by dewatering, desilting, repair of the embankments and provision of inlet and outlet. The pond may be owned by the individual or taken on lease in which case the lease period should be more or coterminous with the repayment period. The eligible items of pond development are as follows:

| | i) | Desilting of existing ponds | ii) | Deepening of shallow ponds. | iii) | Excavation of new ponds. | iv) | Impoundment of marginal areas of water bodies. | v) | Construction / repairs of embankments. | vi) | Construction of Inlets / Outlets. | vii) | Any other item like civil structures, watchmen sheds, pump sets water supply arrangements / electricity supply arrangements etc. depending on requirements of the project based on its size etc. |

2. Pond Management: | Pond Management plays a very important role in fish farming before and after the stocking of fish seed. Various measures that are required to be undertaken in pre and post stocking practices are tabulated below :

A) Prestocking:
In case of new ponds, pre stocking operations starts with liming and filling of the pond with water. However, the first step for existing pond requiring development deals with clearing the pond of unwanted weeds and fishes either by manual, mechanical or chemical means. Different methods are employed for this.

i) Removal of weeds by Manual/Mechanical or through Chemical means.

ii) Removal of unwanted and predatory fishes and other animals by repeated netting or using mahua oil cake @ 2500 kg/ha metre or by sun drying the pond bed.

iii) Liming - The soils/ tanks which are acidic in nature are less productive than alkaline ponds. Lime is used to bring the pH to the desired level. In addition lime also has the following effects -

a) Increases the pH.
b) Acts as buffer and avoids fluctuations of pH.
c) It increases the resistance of soil to parasites.
d) Its toxic effect kills the parasites; and
e) It hastens organic decomposition. |