Factors to Consider when Selcting your Fish Farming Site
I want to buy a swampy area mainly for fish farming. What will you advise that I consider before buying it? It is not all swampy area that will support fish farming during dry season.
Some are swampy only in rainy season and as such, may not be the best for fish farming unless you don’t want to be an all year round farmer, So be sure of the state of that land.
Also, the security of the area, how easy will it be for water to flow to. you must be sure the place will not be prone to flood during rainy season; otherwise, flood may take all your fish away. All these must be considered before buying the land.
5 Critical Stages of Fish Farming
Aquaculture, also known as aquafarming, is the farming of fish, crustaceans, molluscs, aquatic plants, algae, and other organisms. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions and can be contrasted with commercial fishing, which is the harvesting of wild fish – Wikipedia
STAGE 1:Site inspection and selection
You must make sure the site slopes gently, no ground elevations with good and adequate water source. The soil should be clayey to be able to retain water especially during the dry season.
The site should not be prone to flood during rainy seasons or drought during dry seasons. Let the experts check for soil and water suitability. Nearness of the site to the road and market is also important.
STAGE 2: Site clearing and pond construction
After considering the site to be ideal, clear the weeds and burn to have a clear view of the site. Then mark-out the area to be constructed with rope/line and pegs. The construction involves two methods; Manual or Mechanical.
Moreover, the manual uses pond construction experts to dig the pond. Equipment’s such as pick axe, mattock, shovel, wheel barrow, etc. are used. The Mechanical construction uses excavators, etc. We shall look at the advantages and disadvantages in the two methods in subsequent posts. A well constructed fish pond should have inlet, outlet and overflow pipes. The bottom of the pond should slope gently.
STAGE 3: Pond treatment and stocking
After construction, treat the pond bottom and dykes with quick lime to kill any insects, etc. in the soil and water. Add Organic manure such as poultry droppings etc. to fertilize the pond water for about 1-2 weeks before adding the fingerlings. The size of the fish pond and the type of fish to be reared will determine the number of fingerlings you must stock.
STAGE 4: Pond management
The farmer must observe a number of Best Management Practices in fish farming. Fish feeds and feeding, Bio security measures, water quality tests, etc. Sample some of the fishes regularly to determine their growth performance and to adjust the quantity of their feed based on their new weight gain.
STAGE 5: Harvesting and marketing
Fish is usually sold fresh or processed depending on the plans and decisions of the fish farmer or customers preference.
With these Critical Stages in Establishing Earthen Pond Aquaculture Enterprise considered, you are well on your way to starting a very profitable and sustainable business in aquaculture.
Ecological factors
In site selection for a pond, the ecological factors to be considered include soil, water, topography and climate.
Soil
The soil quality influences the pond productivity and water quality and determines the dyke construction. The properties of soil texture and soil permeability are determined to decide the suitability of a site. Pond bottom should have the ability to hold the water.
Loamy, clay loamy and silt clay soil types are most suitable for pond construction. A good quality gravel should not exceed 10 percent. Thus the rocky, sandy, gravel and limestone soil types are to be avoided.
Evaluation of soil suitability
Soil suitability can be evaluated by three methods.
In squeeze method, take the soil in wet hand and squeeze the soil by closing your hand firmly. If it holds its shape even after opening the palm of your hand, soil is suitable for pond construction.
The ground water test is the best method to evaluate the soil suitability. Dig a pit of one-meter depth and cover it with leaves for a night. If the pit is filled with ground water in the next day morning then a pond could be built. However, in such soils, drainage may require more time due to the availability of sufficient groundwater. If the pit is empty the next morning, the site is suitable for pond construction, but the water permeability has to be tested.
The third method is the water permeability test. Pour the water into the pit and cover with leaves. If no water is found in the pit on the next day morning then there is seepage. To confirm this, once again pour the water into the pit and cover it with leaves. If the water availability is high then the site is suitable for construction. But if the water is drained, the site is not suitable for pond construction. However, the site can be used through use of plastic or heavy clay to cover pond bottom.
Water
An adequate amount of water is required to build the fish farm because water depth needs to be adjusted at regular intervals. Natural water bodies such as reservoir, river, and lakes have stable water quality parameters (Water temperature, dissolved oxygen, pH, alkalinity and water hardness) when compared to borewell and well water.
The site should be away from the flood area. Water should not be acidic or alkaline and if found to be so, suitable correction is to be done by applying lime or organic manure respectively.
The ideal water temperature is 20 – 300C for a fish farm. Water Salinity is the amount of salt dissolved in water. A few freshwater fishes such as tilapia and catfishes grow even in salt water, but the carps can withstand only in freshwater.
Topography
Type of pond construction is determined by the land topography. Normally, flood prone areas and poor rainfall areas need to be avoided. Areas such as industrial zones, fields with underground oil pipelines, irregular land area, fields with high electricity poles and radio masts and highly rooted vegetation area are also not recommended for pond construction.
Biological factors
Biological factors include the species to be cultured, seed source and culture type and they need to be considered before site selection of farm.
Social and economic factors
The ecological and biological factors are a prerequisite for good practices in aquaculture site selection and site management. It is also important to get to know the social and economic background of the area and understand the culture and traditions, particularly ideas and beliefs locally associated with aquaculture practices.
The social fabric, market, and its structure, services directly or indirectly linked with aquaculture sector such as transportation, storage, wholesale market aspects etc are to be considered. The land identified for farm should be without legal issues and fish farming should be accepted by the local people. Other factors include availability of labour, electricity, medical facilities, and transportation.
Fish Pond Construction
An intelligent design and layout is a prerequisite for an efficient pond construction. The excavated earth should be used to construct the dyke and with a plodding slope towards the outlet for the proper draining facility. Preferably construction of pond has to be completed during summer so that the pond can be used for stocking.
Steps in pond construction
Normally, the pond construction includes the following steps.
Step 1: Prepare the site by removing unwanted things such as the trees, bushes, and rock
Step 2 : Construction of seepage-free and secure dyke by using the clay core
Step 3 : Digging the pond and construction of dyke over the clay core
Step 4 : Inlet and outlet construction
Step 5 : Pond dyke covered with soil and plant grass species (avoid long rooted plants such as Rhodes grass and star grass)
Step 6 : Pond should be fenced to avoid theft and entry of predatory animals
Site preparation
The place is cleared of ropes, cables and other items. Trees and bushes and other obstacles that hinder movement of heavy equipment around the site are to be removed – manually / animal power /using machinery. All vegetation including wood are to be cleared in the area (inclusive of 2 to 3 m beyond the dyke for workspace).
Trees within 10 meters surrounding, tree slumps, large stones, are also to be removed. The surface soil which has the highest concentration of roots and organic material is not suitable for pond construction. Hence, about 30 cm of surface soil has to be removed.
Construction of dyke
Dykes should be compact, solid and leak free. A desirable dyke is constructed using 15 – 30 percent of silt, 45 – 55 percent of sand and 30 – 35 percent of clay. A sufficient width of the berm (not less than 1 m) is required to stabilize slope. The embankment slope in horizontal to vertical should be 2:1 in good quality clay soil and 3:1 for loamy silt or sandy soils.
To raise the dyke, the clay buddle (1:2 sand and clay) is deposited as 10 – 15 cm thick layer and it can be formed at centre or inside the waterside of the pond. The crest of the dyke should be sufficient to help allied farm activities and the top of embankment should be above 1 m. Extra outlet is essential on the embankment as a safety measure to avoid damage due to excess raise in the water level.
Digging the pond and construction of dyke
Types of pond
Specific kinds of ponds are required for specific life stage development of fishes – such as nursery, rearing, stocking, treatment and broodstock pond. The rectangular pond is preferred than round shaped corners as it prevents the fish escape during harvest.
An ideal length and breadth ratio of the pond is 3:1 is ideal, with breadth not more than 30 – 50 m. The total farm area can be divided as – nursery – 5 % of total farm area, rearing pond – 20 %, stocking pond – 70 %, and bio pond or treatment pond – 5 % of the total farm area.
Nursery pond – The size of the nursery pond is about 0.01 to 0.05 ha with a depth of 1.0 – 1.5 m. The spawn (3 days old) are stocked in nursery pond, reared for a maximum of 30 days (to attain 2 – 3 cm length).
Rearing tank – a tank where the fry are reared into fingerlings (to attain a size of 10 – 15 cm) and the culture duration is 2 – 3 months. The size of pond varies from 0.05 – 0.1 ha with water depth of 1.5 – 2.0 m.
Stocking pond – In stocking pond, the fingerlings (TL 10 – 15 cm) are reared into marketable size. The culture duration varies from 8 – 10 months. The stocking density varies according to the target fish production. The stocking pond is used as broodstock pond and breeding pond as per the requirement. However, the pond area ranges from 1 – 2 ha with a greater water depth of 2.5 – 3.0 m. There are no hard rules regarding the size of the ponds.
Bio pond or treatment ponds – these are large settling tanks, where the water used for fishponds is purified biologically. They may also be used as stocking pond. However, an even flat bottom is recommended for easy netting operation.
A productive farm should use its higher altitude area for construction of nursery pond followed by the rearing pond. The lowest area of the farm should be used to build the stocking pond, which will help in reducing the cost of construction and increase ease of farm management.
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