FIS 309 Aquaculture (3 Units) PDF

FIS 309: AQUACULTURE (3 UNITS) Topics to be taught: 1. Definition, Aims and types of aquaculture. 2. History, present organization and status of aquaculture in Nigeria. 3. Principle of aquaculture, liming and pond fertilization; food supply; selection of culture species, introduction...

FIS 309: AQUACULTURE (3 UNITS) Topics to be taught: 1. Definition, Aims and types of aquaculture. 2. History, present organization and status of aquaculture in Nigeria. 3. Principle of aquaculture, liming and pond fertilization; food supply; selection of culture species, introduction of exotic species and their implications. 4. Water requirements. 5. Stocking, feeding and harvesting practices. 6. Fish farm design. 7. Economic consideration of aquaculture. This course will be taught by 4 Lecturers and 2 3 field instructors. (Prof Yemi Akegbejo-Samsons, Dr S O Obasa, Dr Mrs FOA George and & Dr h {Mrs} N B Ikeweinwe) O The venues of the course shall be at the designated classrooms in the Oba y - Lipede Multipurpose Building and the University Fish farm/ Hatchery h centre. a y - W Lecture 1 H What is Aquaculture Aquaculture is fish farming. It is the art and science of controlled rearing of fish in ponds, farms and in some instances natural water bodies from hatchlings to matured size. Unlike fish that grow in the wild water bodies, without human interference, in aquaculture, activities such as feeding, fertilization, stocking, reproduction and harvesting are controlled. Aquaculture has been defined by the Japanese Resource Council, Science and Technology Agency as follow: Aquaculture is an industrial process of raising aquatic organisms up to final commercial production within properly partitioned aquatic areas, controlling the environmental factors and administering the life history of the organism positively and it has to be considered as an independent industry from the fisheries hitherto. Aquaculture is organised production of a crop in the aquatic medium. The crop may be that of an animal or a plant. Naturally, the organism cultured has to be ordained by nature as aquatic. Examples are: Finfish: Tilapia, carp, trout, milkfish, bait minnow, yellow tail, mullet, cat fish. Shellfish: Shrimps, prawns, oysters, mussels, pearl oyster for cultured pearls (eg. Japanese pearl oyster, Pinctada fucata). Plants: Water chestnut (Trapa natans). Red alga of Japan, “Norie” (Porphyra). Red alga of Philippines & U.S.A. (Eucheuma) Brown alga of Japan, “Wakame” (Undaria). Aims of Aquaculture i. Production of protein rich, nutritive, palatable and easily digestible human food benefiting the whole society through plentiful food supplies at low or reasonable cost. Oh ii. Providing new species and strengthening stocks of existing fish in y - natural and man-made water-bodies through artificial recruitment W h and transplantation. a y - iii. Production of sportfish and support to recreational fishing. H iv. Production of bait-fish for commercial and sport fishery. v. Production of ornamental fish for aesthetic appeal. vi. Recycling of organic waste of human and livestock origin. vii. Land and aquatic resource utilization: this constitutes the macro- economic point of view benefiting the whole society. It involves (a) maximum resource allocation to aquaculture and its optimal utilization; (b) increasing standard of living by maximising profitability; and (c) creation of production surplus for export (earning foreign exchange especially important to most developing countries). viii. Providing means of sustenance and earning livelihood and monetary profit through commercial and industrial aquaculture. This constitutes the micro-economic point of view benefiting the producer. In the case of small-scale producer, the objective is to maximise income by greatest possible difference between income and production cost and, in the case of large scale producer, by maximising return on investment. ix. Production of industrial fish.  Types of Aquaculture The different kinds of aquaculture are: i. Static water ponds. ii. Running water culture. iii. Culture in recirculating systems: in reconditioned water and in closed systems. iv. Culture in rice fields. v. Aquaculture in raceways, cages pens and enclosures vi. Finfish-culture cum livestock rearing. vii. Hanging, „on-bottom‟ and stick methods of oyster culture. Based on the number of species that are cultured in a system aquaculture h may be classified into: (a) Monoculture and - O (b) Polyculture. hy - W (a) Static freshwater ponds a y Ordinary fresh water fish culture ponds are still-water ponds. They vary a H great deal in waterspread area and depth. Some are seasonal and some perennial. The ponds may be rainfed (also called sky ponds) and/or may have inlet and outlet systems. The water supply may be from a stream or a canal or from an underground source such as wells, tubewells etc. (b) Running water culture In Japan, at places where there is abundant supply of water, common carp is cultured in running water ponds. The most intensive common carp is cultured in running water ponds. A very high common carp production rate of 980 t/ha has been achieved at the Tanka Running water fish farm in Japan where there is plentiful supply of running water of high dissolved oxygen content and optimum range of temperature for feeding. Running water culture of common carp is done in a small way in Europe, Indonesia and Thailand. (c) Culture in recirculatory systems This system is comparable to running water culture system except that in the latter, water goes waste whereas here the same water is reused. In this system, water is filtered continuously and recirculated, often after aeration, to the fish pond. The filtering element is a biological filter comprising 3 – 4 cm diameter pebbles, or honey-comb synthetic strips, designed to arrest faecal matter and to denitrify catabolic wastes through bacterial action. (d) Culture in Rice Fields Culturing fish and growing rice together in the same paddy fields is an old practice in Asia and the Far East. Interest in producing rice and fish h together had declined in recent years because of use of fish-toxic pesticides - O required to protect high yielding varieties (HYV) of rice introduced as part of hy green revolution in Asia. a y - W (e) Aquaculture in Raceways: Cages, Pens and Enclosures H Marine aquaculture farms may be located at six possible sites viz. either on the shore with pumped sea-water supply; in the intertidal zone; in the sub- littoral zone, or offshore with surface floating, mid-water floating or seabed cages. The first three are enclosures and the last three cages. (f) Finfish Culture-cum-Livestock Rearing Commercial scale fish-cum-duck culture is practiced in Central European countries such as Czeckslovakia, East Germany, Hungary and Poland, as well as in Taiwan Province of China. This is a synergic system of mutual benefit to each organism cultured: duck droppings manuring the pond, duck foraging consuming a variety of unwanted biota for fishculture such as tadpoles, frogs, mosquito and dragonfly larvae, molluscs, aquatic weeds etc. (g)Monoculture Monoculture, as the name implies, in the culture of a single species of an organism in a culture system of any intensity, be it in any type of water, fresh, brackish or salt. e.g. Fresh water: Catfish, Clarias gariepinus in Africa. Common carp in East Germany, Common carp in Japan Tilapia nilotica in several countries of Africa, (h) Polyculture Polyculture, as the name implies, is the culture of several species in the same waterbody. The culture system generally depends on natural food of a waterbody sometime augmented artificially by fertilization and/or by h supplementary feeding. If artificial food is given it is a common food - O acceptable to all or most species that are cultured. hy e.g. Fresh water: Polyculture of Clarias gariepinus and tilapias in Africa. a y - W H Lecture 2 History, Present organisation and Current status of Aquaculture in Nigeria. The agricultural history of Nigeria is intertwined with its political history. This is discussed broadly in the context of the varying constitutional frame works, viz: Colonial, the Internal Self Government and the Post-1960 periods, according to sectors. A. The history of fisheries development in Nigeria is a comparatively recent one, although reports have shown that a fishing company operated from the coastal waters of Lagos long before 1915. Deliberate efforts at developing the country's fisheries can be said to date back to the Second World War when, because of the naval blockade of the high seas, the then  Colonial Administration decided to develop the country's local resources, including fisheries. B. A fisheries organisation was established in 1941 as a Fisheries Development Branch of the Agricultural Department of the Colonial Office and a Senior Agricultural Officer was appointed to conduct a survey of the industry and its possibilities. The headquarters was sited at Apese village and later at Onikan in Lagos, from where, assisted by a part-time voluntary officer, preliminary experiments in fish culture in brackish water ponds at Onikan were carried out and sur veys were conducted on the canoe fisheries of Apese village and Kuramo waters around h Victoria Island, Lagos. A small fisheries school was also y - O established at Onikan. - W h H a y C. Early in 1945, the Fisheries Development branch was temporarily transferred from the Agricultural Department to the Development Branch of the Secretariat. A Fisheries Development Officer was appointed and a Five-Year Plan for Fisheries Development was formulated and incorporated in the Ten-Year Plan of Development and Welfare in Nigeria, laid on the table of the Legislative Council on 13th December, 1945. D. From this date to 1947, the Branch became a section of the Department of Commerce and Industries with a Principal Fisheries Officer in charge. In addition to the brackishwater fish culture experiments and canoe fisheries surveys, other activities were initiated. Small motor fishing crafts were acquired for exploratory fishing in the estuaries, lagoons and creeks. It was considered "that these fisheries should receive priority treatment at this stage in Nigeria over sea fisheries". E. Between 1948 and 1950, major efforts were made at extending the artisanal fisheries pro gramme to other coastal areas of Nigeria. An active extension service was established to demonstrate the benefits of improved fishing techniques and gear to the coastal canoe fishermen. A Fish Farmer was appointed to extend this aspect of production and this culminated in the establishment in 1951, of a 160ha industrial- scale fish farm at Panyam on the Jos Plateau. By the end of this period, the branch had grown to become the Federal Fisheries Services under the Federal Ministry of Economic Development. F. Under the 1954 Constitution of Nigeria, the fisheries Oh organisation was split between the Federal and Regional y - Governments. The Federal Fisheries Service of the Federal W h Ministry of Economic Department was headed by a Director y - with laboratories and headquarters in Lagos. The Western H a Region Fisheries Division of the Ministry of Agriculture and Natural Resources was headed by a Principal Fisheries Officer. Its headquarters and offices were at lbadan and a Sea Fisheries Section at Lagos, a Marketing and Distribution Section at Warri, Organisation and Inspectorate at Epe and Fish Culture Section at lbadan and Asaba. The Eastern Region Fisheries Division of the Ministry of Agriculture was under the charge of a Principal Fisheries Officer and the headquarters at Aba and an outstation at Opobo. G. The Fisheries Section of the Ministry of Agriculture of the Northern Region was under the charge of a Senior Fisheries Officer while the headquarters was located first at Baga and later at Malarnfatori, Lake Chad. In addition, the Northern Region Fish Farm at Panyam was placed under the administration of the Region's Ministry of Trade and Industry, and was under the charge of a resident Fish Farmer. The  Federal Fisheries Service had the constitu tional responsibility for fisheries development and research in the Lagos Federal Territory and research in any other part of the country where the Regional Government invited it to carry out any specific research activity. H. The period 1956-66 witnessed great expansion in Nigeria's fishing activities. In the coastal trawler fleet, from a single registered trawler in 1956, the fleet was built up, by 1960, to 13 while the total fish catch increased ten-fold during the period. This level of production was sustained up to 1963 but catches fell in 1964-66, following heavier exploitation of the Lagos Oh fishing grounds. By this period, however, commercial quantities y - of prawns had been discovered in the eastern parts of the W h country and many of the vessels converted to prawn fishing, y - thus reducing the pressure on the fish stock. By1970, the H a fishstock had fully recovered and the expansion of inshore fishing activities was becoming so rapid that plans were then made to regulate fishing in order to conserve the rather limited resources. The period also saw a considerable increase in the artisanal fisheries. This has been attributed to the concentration of fishing activities close to the rich grounds; higher money returns for efforts; general improvement in processing, storage and distribution methods; improvement in the type of fishing craft used and, especially, to the higher gear efficiency due to a complete changeover to synthetic fibre. The general result was that the contribution of fisheries to the country's QDP quadrupled between 1960 and 1970. I. Awareness Years (1991-2001): In this decade aquaculture witnessed some level of robust development in term of awareness both among private investors, institutions and government as sure means of producing cheaper protein and source of employment. The picture at the turn of this decade evidenced clearly the unmitigated failures of government farms especially Agricultural Development Programmes, (ADP) in most of the states. In spite of the huge fund from the World Bank as part of its intervention programme to boost fish production the objectives were clearly off from being realized as the progress recorded can at best be described as marginal. The number of manpower increased although quality of expertise remained suspicious. Some levels of growth were recorded, profile of investors and scale of investment saw some level of improvement in the number of small (31,500-100,000kg/ha/yr) and medium scale entrepreneurs with some fish farm having an average output of 10 ton/ annum. Although, the appreciable Oh degree of success of these fish farms had been traced to foreign y - support as provided by their foreign technical or financial W h partners; it showed the level of production which can be y - attained once the right mix of technical and financial input is H a made available. INTRODUCTION TO FISH POND CONSTRUCTION AND MANAGEMENT FIS 312 LECTURE GUIDE O h y- BY: - W h H a y A.O. AGBON & F.I. ADEOSUN Ph.D. Ph.D. University of Agriculture, Abeokuta POND CONSTRUCTION A pond is a water enclosure or a confined body of water where fish are raised or reared under a manageable controlled condition. Pond could either be earthen or concrete. Nowadays fish are raised in plastics, fiber- stars and wooden rafts which are either locally fabricated or imported from developed countries. But here, in this course, emphases are laid only on earthen and concrete pond constructions. TYPE OF PONDS (Earthen) There are two major types, namely: (i). Excavated pond (ii). Embankment/ pond h Sometimes, depending on the terrain or topography of the site, there is what we called y- O h excavated- levee pond, barrage pond and contour pond. a y - W H During the lecture the distinctions shall be made clear to students diagrammatically Site selection for fish pond construction: The failure or success of fish farm enterprise depends on the selection of a good site. The layout and the management of fish farm will largely be influenced by the kind of site selected. The site has the following influences: (i). strongly affects the cost of construction (ii). amount of fish that can be produced (iii). ease of pond management (iv). the economics of the enterprise Decisions prior to site selection:  a) Do i have a clear ideal of the type of fish farm I want to construct b) Of what production level is my target? c) What is the system of culture to be adopted? d) Which fish species should be produced? e) Is it necessary to produce fingerlings for the farm? f) At what stage of fish should you start selling? Answers to these questions will assist greatly during site selection exercise Decides what you want to do O h h y- - W Define kind of site needed H a y Can you find this site? Reconnaissance Survey Ca you change the site that is needed? water - soil - topography Can you change what you want to do? Look for alternative solutions Figure 1: Site selection decision-making cycle Factors to consider when selecting site for fish farm construction a) Water –– quantity, quality, source, activities around it b) Nature of soil –– texture, permeability, retention ability, etc c) Topography of the land d) Environmental consideration e) Accessibility f) Vegetations density/cover g) Expertise Other important factors include: O h y- h) Proximity and size of market - W h i) Poaching a y j) Availability of farm inputs H Students are to be given practical exposure with training manual on the necessity of these aforementioned factors Detailed planning for fish farm construction Once the site has been selected, then initiation of planning begins. There are two main related components of planning in construction. These include: a) Organizational planning ––decides where, how and which order the farm is to be built. b) Physical planning –– decides on layouts, detailed design and earthwork. SITE SELECTION RECONNAISSANCE SURVEY Water - soil - topolograpy No Does site meet requirement? Return to site selection process Yes DETAILED SURVEY Yes Soil - Topography O h Try out sketches of the layout h y- Do they meet your needs? Is there a problem with? y - W Yes the site? H a Prepare detailed draft layout Earthworks and water levels satisfactory? No ALL ok? Yes Prepare final detailed Design Prepare final evaluation of the site Figure 2: Flow - chart on matching the fish farm and its layout to the selected site Figure 2 is to be used in ensuring proper and appropriate appraisal of the work to be done. Assignment: students are expected to visit any chosen location at COLERM field and carry-out fish farm site selection exercise and prepare a report Things include: O h 1. Time of construction h y- 2. who will construct the fish farm ? y - W 3. How will the construction be carried -out? H a These when critically considered, may lead to further activities such as a) Some more detailed plan and drawings b) A series of specifications for the contractor c) A detailed schedule of activities will be drawn. Steps involved in earthen ponds construction The following steps are required: Clearing of proposed site Setting-out which involves site clearing Mark-out the areas inlet and outlet Topsoil removal and storage Construction of embankment Construction of inlet drainage pipes / water control structures Construction of screen at both inlet and outlet. Steps involved in block tanks for fish farming Clearing of proposed site Settings-out which involves pegging and lining with the rope Topsoil stripping to form strong basement Surface blinding with concrete mixture (sharp sand, cement , and gravel/ granite at ratio 3:1:6) Block laying and stuffing of holes with concrete mixture Placement of water inlet and outlet pipes Plastering of tanks h Calculating dike and excavation volumes y- O Width of the dike base - W h Base width = crest width + (CH x SD) + (CH x SW) H a y Where CH (in m) = construction height SD = slope ratio of dry side SW = slope ratio of wet side While estimating this, use the constructing height as well as the settlement EXERCISE: A 0.04ha pond has to be built in clayey soil with dikes 1.50m high and 1m wide at the top. If SD = 1.5: 1 and SW = 2:1. Calculate the base width of the dike (Hint : settlement allowance of expanded clay volume is 20%). Solution: Design height = (100% – 20%) = 80% of constructing height Construction height = 1.50m/0.80 = 1.88m Dike base width = 1m + (1.88m x 1.5) + (1.88m x2) = 7.55m Note: Design height, DH, is the height dike should have after settling down to safely provide the necessary water depth in the pond = Water depth + Free board. Construction height, CH, is the height the dike should have when newly built and before any settlement takes place. =design height + settlement height CH = DH ÷ [(100 - SA) ÷ 100] Calculating the cross-section of a dike on horizontal ground O h y- For the above 0.04-ha pond to be built in clayey soil, calculate the size h of the cross-section of the dike as: a y - W area 1 = 1 m x 1.88 m = 1.88 H m2; area 2 = (1.5 x 1.88 m) x (1.88 m ÷ 2) = 2.6508 m2; area 3 = (2 x 1.88 m) x (1.88 m ÷ 2) = 3.5344 rn2 cross-section = 1.88 m2 + 2.6508 m2 + 3.5344 m2 =8.0652 m2. Calculating the cross-section of a dike on sloping ground The cross-section of a dike on sloping ground can be calculated most easily using a scale drawing. (a) Draw a horizontal line from D, meeting AE at E'. (b) Draw a horizontal line from C, meeting BF at F'. (c) Draw a vertical line PO down the centre line of the dike. (d) Cross-section = ADE + AEFB + BFC = 0.5(AE x DE') + (AB x PO) + 0.5(BF x F'C). Calculating the cross-section of a dike on sloping ground using a scale drawing Calculating the cross-section of a dikeCalculating the cross-section of a dike on irregular ground using a scale drawingon irregular ground using squared paper O h h y- a y - W H 1 cm = 0.5 1 square of 0.5 m x 0.5 m = 0.25 m2 15.2 squares x 0.25 m2 = 3.8 m2 m Calculating the volume of dikes on horizontal and regular ground To estimate how much soil will be needed for the construction of a dike, you need to know its volume. The calculation method depends on the site topography and on the type of pond to be built. If the topography of the construction site is reasonably flat (less than 0.30 m difference in average site levels) and regular, you can calculate the volume of the dike (in m3) by multiplying the cross- section of the dike(in m2 and halfway along the dike for an average area) by its length measured along the centre line (in m). EXAMPLE Using the figures from the example above, the cross-section of the dike equals 8.0652 m2. If the length of the dike to be built is 20 m x 4 = 80 m, its volume is 8.0652 m2 x 80 m = 653.216 m3. Calculating the volume of dikes on sloping or irregular ground If the topography of the site is more steeply sloping or more irregular, you cannot calculate the volume of the pond dikes just by using one cross-section. There are several possible methods, depending on the type of ground and the accuracy you require. With a first group of methods you can calculate the dike volumes by using averages of the dike cross- sections or you could use the average of the cross-sections at the corners of the dike. O h y- EXAMLPE W h A 400-m2 (20 x 20 m) pond is to be constructed with wall heights of 0.5 m at corner A, 0.3 m at y - corner B, 1.1 m at corner C and 1.5 m at corner D. Crest width is 1 m and side slope 2:1 on both a sides. The cross-section areas at each corner are: H A: (1 m x 0.5 m) + 2 x (0.5 m x 0.5 m x 1 m) = 1.5 m2, B: (1 m x 0.3 m) + 2 x (0.5 m x 0.3 m x 0.6 m) = 0.48 m2, C: (I m x 1. 1 m) + 2 x (0. 5 m x 1. 1 m x 2.2 m) = 3.52 m2, D: (1 m x 1.5 m) + 2 x (0.5 m x 1.5 m x 3 m) = 6.0 m2. Average area for wall AB = (1.5 m2 + 0.48 m2) ÷ 2 = 0.99 m2 and volume for wall AB = 0.99 m2 x 20 m = 19.8 m3. Similarly: for BC, average area = 2 m2 and volume = 40 m3; for CD, average area = 4.76 m2 and volume = 95.2 m3; for DA, average area = 3.75 m2 and volume = 75 m3. Consequently, total volume of dikes = 19.8 m3 + 40 m3 + 95.2 m3 + 75 m3 = 230 m3. Average of areas at corners of dike For a more accurate measurement of dike volume on rough ground, you should apply the following formula, known as Simpson's rule, where: V = (d ÷ 3) x [A1 + An + 4(A2 + A4 +... An-1) + 2(A3 + A5 +... An- h 2)]. Proceed as follows: y- O h (a) Divide the length of the dike into an odd number n of cross-sections at equal intervals of d W metres. a y - (b) Calculate the area A of each cross-section as explained earlier. H (c) Introduce these values into the above formula. The dike is 60 m long. (a) At intervals d = 10 m, identify seven cross- sections A1... A7 and calculate their respective areas to obtain A1 = 10 m2 ; A2 = 16 m2; A3 = 18 m2 ; A4 = 11 m2 ; A5 = 8 m2; A6 = 10 m2 ; A7 = 12 m2. (b) Introduce these values into the Simpson's rule formula: V = (d ÷ 3) [A1 + A7 + 4(A2 + A4 + A6) +2 (A3 + A5)]. (c) Calculate V = (10 m ÷ 3) [10 m2 + 12 m2 + 4(16 m2 + 11 m2 + 10 m2 + 2(18 m2 ÷ 8 m2)] = 740 m3. Calculating volumes of excavated material You will need to know excavation volumes for: topsoil; borrow pits, dug near an earth structure to provide the material for its construction; excavated ponds, to provide the pond volume required; other structures such as harvest pits, supply channels, etc. You will normally have to remove the topsoil before you reach soil good for construction material. Levels should therefore be taken from the base of the topsoil layer. In most cases, the sides of the excavation should be sloped to prevent them from collapsing. In many cases (ponds, channels, etc.) these will be of h specified gradients. y- O - W h H a y For reasonably flat, level surfaces, where excavated width is at least 30 times the depth, volume of excavation can be estimated as: V = top area x depth of excavation. Where the width is less than 30 times the depth, you should correct for side slopes as follows: V = [(top area + bottom area) ÷ 2] x depth. EXAMPLE A 400 m2 (40 x 10 m) area is to be excavated, 1 m deep, with side slopes 2:1. As the width (10 m) is less than 30 times the depth (30 x 1 m), the first method is not accurate (estimated volume would be 400 m2 x 1 m = 400 m3).  Use the second method, where top area = 400 m2 and base area=base length x base width. Base length = 40 - (2 x slope x depth) = 40 - (2 x 2 x 1 m) = 36 m Base width = 10 - (2 x slope x depth)= 10 - (2 x 2 x 1 m) = 6 m Base area = 36 m x 6 m = 216 m2 Average area = (400 m2 + 216 m2)÷ 2 = 308 m2 Volume therefore = 308 m2 x 1 m= 308 m3. Above all, for precision, prismodal formula can be used to calculate the volume of soil excavated h from pond area (excluding topsoil area): y- O - W h V= (A+4B+C)/6 *D Where A = Top surface area H a y B = Mid-depth surface area C = Bottom surface area D = Average depth of excavation How to calculate the volume of water in the pond You have thus calculated the surface area of the Examples pond and the average water depth of the pond. Now, using the figures you have found, you can calculate the volume of water in the pond by Surface Average Water multiplying the surface in square metres (m2) by area water volume the average water depth in metres (m) to get depth  the volume of the pond in cubic metres (m3). (m2) (m) (m3) SURFACE AREA x AVERAGE DEPTH = VOLUME 235 x 1.0 = 235 450 x 1.2 = 540 2500 x 1.5 = 3750 Note: 1 cubic metre (m3) = 1000 litres (l). To express water volume (in m3) in litres (l) multiply by 1000. To express water volume (in l) in cubic metres (m3) divide by 1000. O h h y- y - W References H a FOA Training Series: simple methods of Aquaculture pond construction  O h hy- a y - W H Anticipate O h hy- a y - W H TEAM SYNERGY AQUACULTURE - O h h y y - W Ha FIS 309 By: Prof. W.O. Abdul 1  O h y- h y - W Ha SITE SELECTION AND FISH POND CONSTRUCTION Types of Aquaculture 2 Land based e.g earthen ponds, concrete tanks, recirculating system (RAS), raceway etc O h hy- a y-W H Water based e.g cages, pens O h hy- a y-W H 4  Types of pond A. Diversion ponds : It involves bringing water from a source such as stream, river, borehole etc to the pond. There are two sub-types. O h h y- These include: a y -W i. Embarkment pond: building dikes above the ground level H ii. Excavated pond: Dug out below the ground level B. Barrage ponds: made by building a dike across a natural flowing stream. It is easy to construct but difficult to control wild fishes and also silt turbidity during raining season 5  Site selection for Aquaculture Projects Selection of a suitable site for an aquaculture project will influence construction h costs and affect the ultimate success of the aquaculture enterprise. Though, ideal y- O site is often not available, so one needs to compromise. -W h H a y A number of factors must be considered when selecting a site. These include: Ecological Biological and Socio-economic factors 6  O h hy- a y-W H 1 Site selection A. Ecological Location: site should be near service components such as to roads, electricity and other h communication networks y- O h Topography: land slope should be suitable; steepy slopes require more excavation (cut and fill) -W and higher construction costs. Saucer-shape land is most preferable. The recommended slope H a y should be 2 - 4% Soil: soils with low infiltration rate are suitable for fish pond construction e.g. Impermeable clay that can be easily compacted and made impervious to prevent seepage. Meanwhile, soil also influences pond productivity and water quality 2 A simple soil test for pond construction A: Take a sample of the soil and wet it well; B: Knead it with your hands until it becomes a stiff plastic mass; O h y- C: Make several balls, each about 10 cm in diameter; -W h a y D: Put the balls in still water about 45 to 60 cm deep. You can H use a hole dug in the ground and lined with a plastic sheet or a large container such as a 200 l metal drum; E: Look at the balls of soil every few hours at first, and later several times a day; F: If the balls do not fall apart but remain intact for at least 24 hours (F), the soil is good for embankment construction. CLASSIFICATION OF SOIL BASED ON INFILTRATION RATES Some other soil tests may also Soil Type Infiltration rate be carried out to further (mm/hr) confirm the site O h y- suitability/quality. These Clay 1-5 -W h include: a y Clay/loam 5-10 H a. Squeeze test Silt loam 10-20 b. Permeability test c. Groundwater test Sandy loam 20-30 Sandy 30-100 4 Squeeze method ▪ Randomly at a depth of 1m, collect a handful of soil and moisture Squeeze the sample of soil and if it holds its shape after opening the palm, the soil is good for pond construction - O h h y Dig a hole with a depth of y a - W Groundwater test--- usually during the dry season to get a reliable result H 1m Cover it with leaves for 24hrs to limit evaporation If the hole is filled up with water the next morning, it shows the water table is high. *Note that any pond built here will require more time to drain If the hole remains empty the next morning, the site is suitable for pond construction 5 Permeability test Dig a hole of about 1m deep and fill with water to the top Cover with leaves to minimise evaporation O h Evaluate seepage the next day as the dikes of the hole would have become h y- saturated with water a y -W Refill the hole with water to the top, cover with leaves and check the next day H If the water level is still high, the soil is suitable for pond construction If the water is lost totally to seepage, the site is not suitable for pond construction unless the bottom is lined with PVC (pond liner) or sealed up with heavy bentonite clay 6  O h hy- a y-W H 1 Water Supply: This is the most limiting factor in site selection for aquaculture project. O ✓Quality must meet the requirements-for hculture y ✓Source must be dependable and close to the site ✓ Must be available all year-W h culture H a y round or in accordance with cycles of ✓ Must be free from pollution 2  Meanwhile, the quantity of water required is dependent on: ✓Culture species ✓System of culture e.g. static or running water system O h y- ✓Management practices -W h ✓Stocking density a y ✓Skill of the culturist, e.t.c. H Water supply must satisfy the losses caused by: ✓Evaporation ✓seepage looses ✓Oxygen depletion ✓waste disposal Therefore, 0.28cum/min/ha is recommended as flow rate to compensate for the loss Hydrological and meteorological information Time series climatological data is required to plan aquaculture projects. h This include mean monthly temperature, rainfall, evaporation, humidity, y- O solar radiation, flood records, wind direction, e.t.c. -W h H a y 4 B. Biological ✓Choice of fish species e.g. gustatory value, growth, trait ✓Fingerlings supply O h y- ✓Feed requirements and supply -W h ✓Disease risk and management H a y ✓Processing potential and requirement ✓Predator control- e.g. birds follow the local conservation regulations 5 C. Economic and social factors O h y- ✓Working capital available h ✓Availability of land a y -W ✓Culturist skill level/management skill H ✓ Labour required and cost ✓Nearness to market ✓Safety and security e.g. public health and working safety, EIA, poaching and vandalism ✓Employment i.e. aspect of job creation for local residents ✓Legal matters 6  Practical Session (Duration: 1 Hour) - O h h y - W water supply for a medium scaleyland-based Ha Discuss the procedure for selecting a suitable site in terms of topography, soil and aquaculture project in your locality 7  O h hy- a y-W H 1 Steps involved in earthen pond construction O h y- ✓ Site clearing/stumping -W h y ✓ Marking/staking out H a ✓ Top soil stripping/removal ✓ Excavation ✓ Dyke preparation/compaction ✓ Installation of water supply facility/drainage ✓ Testing for leakages ✓ Grassing ✓ Liming and fertilization 2 ✓ Impoundment Staking out O h hy- a y-W H 3 Removal of topsoil O h hy- a y -W H 4 Compacting dike manually O h hy- a y-W H 5 Steps involved in block tank construction ✓Marking/staking out ✓Top soil stripping O h ✓Blinding h y- -W ✓Block laying H a y ✓Stuffing ✓Installation of outlet ✓Plastering ✓Installation of water supply pipes ✓Curing ✓Impoundment ✓Stocking 6 Construction of block tank O h hy- a y-W H 7 Prescribed texts Cowx, I.G. (1992). Aquaculture Development in Africa. Training and Reference Manual for Aquaculture Extensionists. London Lawson, T. B. (1995). Fundamentals of Aquaculture Engineering. Chapman h and Hall, London y- O h Yoo, K. H. and Boyde, C. E. (1994). Hydrology and Water Supply for Pond y -W Aquaculture. Chapman and Hall, London H a Egna, H. S. and Boyd, C. E. (Eds). (1997). Dynamics of Pond Aquaculture. CRC Press New York Losordo, T.M., Masser, M. P. and Rakocy, J. E. (1998). Recirculating Aquaculture Tank Production Systems. An Overview of Critical Considerations SRAC Publication No. 451 8 POND SITE SELECTION AND SURVEY Site selection There are many factors to be considered when selecting the location of your pond. Think Economically Choose an area where a limited amount of excavation will be required to contain, or hold back, a large volume of water. A valley were a dam can be constructed at a narrow pass is a good example. Think about where you will get the water to fill your pond. There are four general water sources to consider. Overland Drainage: This is surface runoff from precipitation, melting snow or a spring flowing overland. Drainage area and annual precipitation rates will determine if the water supply will be adequate. In Monroe County it is recommended that when building a pond you have a minimum of 20 acres of watershed to 1 acre of water. Ground Water: Ponds which acquire water mostly from ground water are often called water table ponds. They are built by excavating below the water table at the location. The level of the water will be equal to that of the water table at any given time. In some h cases an underground spring may be present. Springs flow year round regardless of y- O season. h Impounding Flowing Waters: This can be a plentiful water source for a pond. However, impounding flowing water can have adverse effects. It can block fish - W passage, warm the water downstream, add excess nutrients to your pond and cause a y sediment from upstream to fill in your pond. The latter will require occasional removal. H Heavy flows can also be difficult to contain. Often federal, state and local permits are required. Generally, more problems are encountered with this type of pond and are not recommended to be built in this way. Other Sources: If water cannot be obtained from the preceding natural sources, other options are available. Diversion ditches can be constructed to catch water from overland drainage that may bypass the pond. Roof runoff can be collected and sent to the pond or a sump pump drain can be directed to the pond. If your house and out buildings are nearby, place a snow fence or plant a living fence up wind of your pond. This will reduce evaporation in the summer and intercept snow in the winter to fill the pond. Winter snow will recharge the pond when it melts in the spring. Moving water is expensive, if the pond is to be used for irrigation or fire protection, it should be located in a place that is accessible to the fields and buildings you have in mind. Livestock ponds should be evenly distributed throughout a pasture and animals should not have to travel farther than ¼ mile over rough terrain or 1 mile over even terrain. A pond used for recreation must be accessible to emergency vehicles. If it is for public use, there should be surrounding space for other public facilities and a gently sloping shore if swimming will occur. If a pond is being built to provide wildlife habitat, a quiet secluded area is best. Pollution Pollution of the water in your pond should be an important consideration when selecting a site. Pollution can come from many sources, including crop land and lawn runoff, livestock farm drainage, road drainage, septic systems and waterfowl waste. If possible, eliminate these sources of pollution. Do not over apply fertilizer, use erosion control practices and properly design and maintain you septic system. If unavoidable, divert the drainage from you pond. Construct diversion ditches or other stormwater management systems to deal with the runoff. If possible, never construct your pond less than 150 feet from a septic system. Be aware of how your pond will affect neighboring property. Do not back up water or release overflow water onto adjacent property unless it is into an existing drainage ditch. In the case that your dam fails, look to see what would be in the path of the rushing water, assess how severe the effects would be and consider your liabilities. Certain regulations must be met if the NYSDEC issues a dam permit. If these regulations are not followed, construction on the dam may be not be allowed to continue. Soil Test Pits Test pits are holes dug in the earth at various points in the proposed pond location. It is very important that a number of test pits are dug, and that they are inspected by someone who is familiar with soils. They are excavated to a depth two feet below the planned depth of your pond and are used to determine the feasibility of your site for a pond. This allows you to detect any potentially problematic areas such as bedrock, or gravel and sand seams h which may cause you to lose water from your pond. It also allows you to calculate how O much good material will be available to build your dam and other structures. This is a very y- important step, which can help to save money later on. It can cost much more to deal with h hazards that could have been avoided W Regulations on the land and/or permits that are required y - Depending upon size, intended use, capacity of water impounded and location of a your pond, there may be regulations that must be considered. State and federal agencies and H sometimes towns often require permits for different aspects of pond construction. A Protection of Waters Permit is needed for the following activities: - Disturbance of the bed or banks of a protected stream or watercourse. Check with the NYSDEC for the classification of any stream you may disturb. The banks of a protected stream extend fifty feet from the shoreline if the slope of the shore is less than 45 degrees, or to the crest of a slope if the slope is 45 degrees or greater. - Construction, reconstruction or repair of dams and other impounding structures. A permit is required if a dam is between 6 feet and 15 feet in height and impounds greater than 3 million gallons of water or if the dam is greater than 15 feet and impounds greater than 1 million gallons of water. The height of a dam is measured from the downstream outside toe of the dam at its lowest point to the highest point at the top of the dam. Maximum impounding capacity is measured as the volume of water impounded when the water level is at the top of the dam. *Exception to Dam Rules: If the dam is less than 6 feet high, constructed with settled fill, the NYSDEC does not require a permit for construction. A Freshwater Wetlands Permit is required if you plan to disturb land within 100 feet of a NYSDEC regulated wetland. Contact the NYSDEC Region 8 office to find out if you are within this type of regulated area. An Aquatic Pest Control Permit is required if you wish to apply pesticides to New York State waters greater than 1 acre or with an outlet to surface waters. A Farm Fish Pond Permit is required for a body of water impounded by a dam with a surface area, when full, of 10 acres or less. This permit entitles the owner to manage the pond for the production of fish. Page 10 A Stocking Permit is required to place fish or fish eggs in any New York State waters. A Triploid Grass Carp Permit is required to import, export, own or possess, acquire or dispose of live Grass Carp or hybrid Grass Carp within New York State or to place them in New York State waters. A Mined Land Reclamation Permit is required for excavating or moving off-site 1000 tons or more of soil and minerals. The U.S. Army Corps of Engineers also regulates navigable waters, wetlands and other water bodies. There is a joint application form available through the NYSDEC. With this form, all application materials will be forwarded to the Army Corps and you will be contacted if necessary. In addition, it is recommended that you call your town hall for any local regulations that may concern your project and Dig Safely New York to be sure there are no pipelines or h cables buried across your site. (See Appendix A and B for phone numbers) y- O These departments and agencies often require 60 days or more to process applications. Though they do attempt to do so in a timely manner, unforeseen circumstances h can cause applications to be delayed. To ensure that your project can begin on time, be sure - W to send in applications early and allow ample time for them to be processed. y Excess Soil H a Much of the soil excavated from your pond site may be used to build the dam, fill low lying areas nearby and to replace topsoil on disturbed areas. Soil may be left over and can be expensive to move. Consider selling the topsoil, it is a valuable commodity. Many contractors and land owners may be interested in purchasing it and transporting away from your site. Contact your town hall and the NYSDEC to be sure there are no ordinances regarding moving the soil offsite first. (See Appendix A and B for phone numbers) Or you may want to use the topsoil to build something additional on your land. Small mounds or hills can be constructed and then seeded and planted with vegetation. This may create an aesthetically pleasing landscape in addition to wildlife habitat. Costs A pond can be an expensive, but worthwhile endeavor. Many factors can influence the cost of your pond. Be prepared for unforeseen circumstances that may arise and produce additional costs. (i.e. a large storm that requires the contractor to drain the pond before continuing) One way to prevent some hazards is to dig test pits before starting construction. Test pits are an important preliminary step to pond design and are discussed further in “Site Selection”. TYPES OF PONDS Excavated Pond An excavated pond is often built on level terrain and its depth is achieved solely by excavation. An excavated pond is relatively safe from flood damage, is low maintenance and can be built to expose a minimum water surface area in relation to volume. This is beneficial in areas of high evaporation losses and a limited amount of water supply. Your budget may limit the size of this type of pond due to the cost of excavation and soil removal. Embarkment Pond This type of pond is built by creating an embankment or dam used to impound water and is usually constructed in a valley or on gently sloping land. It is not recommended to build an embankment pond on greater than a 4% slope. Less excavation may be needed to build this type of pond. However, there are New York State regulations that must be followed regarding the amount of water that can be impounded behind a dam. This will be discussed below. PRINCIPLES OF FISH POND DESIGN AND CONSTRUCTION Pond Structures 1. The dam is an earth embarkment designed to impound water. It must be constructed of material that has a high clay and silt content and is well compacted. As the dam is built, the material should be added in no more than 6 inch layers and compacted. Good dam construction is essential. 2. The core trench is another essential element of a pond. It is constructed by digging a h trench the length of the dam. The trench should be dug beneath the dam to a depth of 2 O feet below your proposed pond bottom elevation. The core trench should be filled in y- with the same material that the dam is built with and compacted in the same manner. h Poor core trench construction, or the lack of one all together, is one of the major reasons W a pond will leak and go dry in the summer. y - 3. The side slopes are described by using a ratio of horizontal to vertical distance along the a slope. For Example, a slope of 2:1 is 2 feet horizontal to every 1 foot vertical. The slope H of the side of the dam facing the water should be 2:1. The slope of the backside of the dam should be a minimum of 3:1 for stability. If you plan to mow it, the backside should be at least 6:1. The slopes are constructed as the dam goes up. The grade of the side slopes elsewhere around your pond will determine the type and amount of vegetation that will grow. Slopes flatter than 2:1 inside the pond will have more aquatic vegetation growth. 4. The top width of the dam should be a minimum of 10 feet wide. It should be seeded and a good vegetative cover should be maintained. The following is a good mix for erosion control and wildlife habitat: 2 lbs./acre White Clover, 10 lbs./acre Perennial Rye Grass, 20 lbs./acre Creeping Red Fescue, 2 lbs./acre Redtop and 8 lbs./acre Empire Bird’s Foot Trefoil. This cover should be mowed about once a year to prevent the growth of woody shrubs. The root systems of shrubs and trees Page 14 can weaken your dam in addition to creating paths for water to seep out. Be sure to mow between August 1st and August 30th. Most ground-nesting birds are off their nests by the 1st and the grasses will have ample time to recover before winter so that you have a good crop in the spring. If you wish to deter geese and ducks from invading your pond, do not keep the grasses around your pond closely manicured. These birds do not like tall grasses where they cannot see stalking predators. 5. Original ground level 6. The level of the principle spillway is that of the proposed water level. It should be able to handle most of the runoff from you pond. There are many different types of principle spillways, the one in the diagram is one type of drop inlet pipe spillway. A professional designer or contractor will be able to help you determine what type of spillway is appropriate for your pond. 7. Anti-seep collars are flat plates attached to the pipe inside the dam. They prevent water from seeping along the outside of the pipe if your soils are not compacted properly around the pipe. 8. The emergency spillway is usually constructed of sod and built to the side of your dam in native soil. It is there to handle excess flows as the result of a storm or spring thaw. It will prevent water from rushing over the embankment and destroying your dam. The emergency spillway should be well seeded and maintained. 9. If the soils around your pond are not of the type that will adequately hold water, it is recommended to line your pond with at least a 12 inch layer of soil with a high clay content. This is called lining your pond, which helps to prevent water from seeping out the sides and bottom of the pond. O h h y- a y - W H INTRODUCTION TO FISH POND CONSTRUCTION AND MANAGEMENT (2 UNITS) FIS 312 LECTURE GUIDE O h h y- a y - W BY: H O.T. AGBEBIPh.D University of Agriculture, Abeokuta  FIS 312: INTRODUCTION TO FISH POND CONSTRUCTION AND MANAGEMENT (2 UNITS) POND MAINTENANCE Once the ponds have been stocked, it is important that the fish are checked every day for signs of stress and the farm in general for any maintenance that might be required. Both activities are preventive measure that should reduce risk of something going wrong around the farm. Those routine inspections should preferably take place during the early morning when the oxygen levels tend to be at lowest and the first most likely to be stressed. It is also good practice to carry out the inspection again most time of feeding as the fish can be observed most easily. During the inspection, the following should be checked and records of the observations h kept: y- O Fish mortalities h Physical and chemical characteristics of waters, particularly oxygen levels. If facilities y - W are available, the farmer should endeavor to monitor climatic production on the farm as a well as water quality parameters. H Check whether fertilization of each pond is necessary. Behavior of fish, particularly for signs of stress e.g. gasping signifies low oxygen levels, poor feeding, errative swimming, lethargy and disease. Pond banks, dams, monks, and outlets for signs of erosion and for leaks. These can get progressively larger if not quickly dealt with. Screens, filters and outlets for debris and blockage which should be subsequently cleared. Excessive weed growth and potential problems. Predators such as snake, lizards, birds and frogs in and around the pond which should be eradicated if possible.  WATER QUALITY MAINTENANCE The survival, growth and consequent production of fish depend to a large extent on the physical, chemical and biological status of the water in the culture enclosure. Therefore, the fish farmer must possess the ability to detect and product quantitatively changes in the limnological status of the water and the effects of different fish farming activities on fish production. Depth: Depth of water in the pond must be kept steady through regular replenishment with fresh clean water to top up for water host by seepaye and evaporation. Low water levels expose fish to the vagaries of predation and extreme temperature fluctuation. High diurnal water temperature associated with shallow grow-out pods (80cm) is an index of low production. This can be improved by adding fertilizers. Low transparency (