PRINCIPLES OF AQUACULTURE (AKU3201)

1. PRINCIPLES OF AQUACULTURE(AKU3201) Soil & Water quality

2. Site selection • Water & soil source • Topography • Location • Labour source • Environmental impact

3. Climate condition • Availability of skilled labour • Public utilities security • Easy communication system • Protection from natural disasters • Access to materials

4. Water • Water Sources • Municipal water • River/Lake/Dam • Underground • Ocean Check water quality

5. Water characteristics: Physical- Temperature, color, turbidity Chemical - Oxygen, pH, Alkalinity, Ammonia, Nitrite Nitrate, Ferum, Pesticide, Herbicide, Salinity Biological - Other organism, predator, pathogen (parasite, bacteria, virus)

6. Topography • Hill slope, valley, riverside, flat land • Need to be considered for – building, infrastructure, pond & tank design, water system • Construction at hill side is costly

7. Climate • Suitable with selected fish species • Otherwise- construction of indoor culture in order to maintain suitable climate (temperate fish, i.e. Salmon- need 20-25’C, therefore not suitable for Malaysia) • Tilapia require higher temperature (above 25’C- not for temperate countries)

8. Access to infrastructure • Near to proper roads • Good electric supply • Processing facilities • Technical assistance

9. Water source • Freshwater • Saltwater • Brackishwater • Quality water -Physical, Chemistry, Biology

10. Topography • Water flow by gravity

11. Others • Easy access for marketing • Seed supply • Room for expansion

12. Environmental impact assessment (EIA) • EIA = Study to identify, predict, evaluate on the impacts on the environment of the proposed project & detail out the mitigating measures prior project approval & implementation e.g, clearing of mangrove swamp forest

13. Soil quality Can contained water • Clay = Not less than 45% clay (>better) • Sand = Not more than 27% (<better) • Sandy clay • Clay + loam soils • Alkaline pH (avoid acid-sulphate soil) • Acid-sulphate soil: contain iron sulfide Iron sulfide + O2 = sulfuric acid

14. Soil test • seepage loss • stability of dikes

15. WATER QUALITY

16. Quran: “We made from water every living thing…” (Quran Al-Anbiya’ 21:30)

17. Water distribution on earth Of all the world’s water supply: • 97% is sea water • 2% is freshwater frozen in glaciers and polar ice caps. • Only 1% is freshwater available for human consumption (95% is groundwater. Only 5% is surface water!)

18. Water quality • Very important! Indicator of success or failure of aquaculture operation • MUST measure, record & manage throughout growing season • Problem: Leftover feed, feces • Affect feeding, metabolism & reproduction

19. Common substances in water • Gases – O2, CO2, NH3, H2S • Minerals – Ca, Mg, Na, K, Fe, Al –usually present as ions or complex molecules. • Soluble organic matter – humic acids, tannins, plant pigments, urea • Suspended inorganic matter – suspension of soil particles • Suspended organic matter – suspended remains of organisms, living planktons, fungi & bacteria

20. Water Quality in Aquaculture In aquaculture, we are concerned about the quality of water in 3 major areas: • Quality of water at source (influent) • Water quality requirements in the culture system • Impact caused by aquaculture effluent

21. Surface water Fresh water source for aquaculture : • Sources: rivers, streams, lakes, ponds and reservoirs. • Often contaminated: high levels of silt & clay particles, predators, disease, pesticides and quality varies with season.

22. Surface water Sea / brackish water source for aquaculture : • Same potential for contamination as fresh-water sources, especially in the coastal area. • Main concern: pump intake location, biofouling of intakes, salinity fluctuations, increased potential for hydrocarbon contamination

23. Surface vs Ground water

24. Alternative water sources • Rainwater: free, unpredictable, only a supplement, often acidic, poorly buffered. • Municipal water: limited potential due to cost/unit volume, also contains disinfectants (e.g., chlorine). • Recycled water: conserves water, environmentally friendly, biofiltration required, high pumping cost.

25. Water Quality in Aquaculture The key challenge in aquaculture is to maintain high growth rates under high stocking densities without degrading the water quality. Poor water quality = poor harvest

26. Different animal, different optimum water quality conditions

27. Water Quality in Aquaculture • Parameters that could influence water quality in an aquaculture pond can be divided into physical, chemical and biological factors. • Physical factors: Temperature, stratification, particulate matter, turbidity and light intensity. • Chemical factors: pH, DO, ammonia, CO2, H2S, nitrite,... • Biological factors: Ecosystem, aquatic plants, macrophytes, plankton, ...

28. Important water quality parameters • Water quality parameters often tested are: • Turbidity / Suspended Solids • Dissolved oxygen • Water temperature • pH • Total Ammonia Nitrogen • Nitrite • Alkalinity/Hardness • Salinity • BOD

29. Portable water quality test-kit

30. 1) Temperature • Poikilothermic? Metabolic rate controlled by temperature • Dif. aquatic species = dif. optimum temperature • Electronic better than glass thermometers

31. Temperature • Controls the biochemicals rate of reaction In general, for each 10°C (18°F) rise in temperature, the metabolic rate of fish doubles (including physiological processes and growth) – Van’t Hoff’s law • Influences the solubility of gases in water – holds less DO at higher temperatures. • Influences toxicity of ammonia. More toxic at higher temperatures.

33. Temperature • All animals have a temperature range, the ‘biokinetic range’, within which they can survive. • This range is limited by the upper and lower tolerance limit, and beyond these critical temperatures the animals may live briefly but would eventually die. • Species with wide range of tolerance - eurythermal • Species with a narrow range of tolerance – stenothermal • Eurythermal fish – Goldfish, Common Carp • Stenothermal fish – Salmonids - < 20-25°C • Temperature acts as a controlling factor regulating metabolism and thereby growth – important for aquaculturists.

34. Linkage of temperature and.. • Amount of feed to be given • Abundance of natural food (phytoplankton & zooplankton) -Important particularly for temperate countries

35. Temperature Consequences of temperature for aquaculture: • Feeding regime must be appropriately adjusted to the water temperature • Know that grow-out period, milt production and ovulation rate will be affected by environmental temperatures • Need to avoid abrupt temperature changes • To minimize stress while transporting fish, it may be advisable to reduce the water temperature thus reducing fish activity and toxic waste accumulation • Cultured species must be carefully selected to match their temperature requirements to the regional environmental temperatures

36. Make sure no rapid oC changes (esp. during fish transfer) • Need to acclimatize first

37. 2. Light penetration • Euphotic zone – Zone where photosynthesis exceeds respiration (1% or more of incident radiation). • In aquaculture ponds, the euphotic zone will normally be less than 1 metre due to dense plankton density. • Secchi disc visibility multiplied by 2 gives an estimate of the depth of euphotic zone in aquaculture ponds.

38. Thermal stratification • Water temperature in ponds is related to solar radiation and air temperature. • Heat is absorbed more rapidly near the surface, making the upper waters warmer and less dense than the deeper waters. • Stratification occurs when the differences in density between these layers become so great that they can’t be mixed by wind • Transfer of heat to lower layers depends on mixing by wind (or aeration). • More turbid water heats up faster than less turbid water because of greater absorption of energy by dissolved and particulate organic matter

40. Thermal stratification • Epilimnion – higher temperature, abundant oxygen, higher pH, less dense • Thermocline – transition zone, variable oxygen, an area of greatest temperature drop (at least 1°C/ m in lakes but generally more in deep aquaculture ponds) • Hypolimnion – lower temperature, lower oxygen, lower pH, denser

43. Thermal stratification How does thermal stratification result in low DO at pond bottoms? • In hot, calm sunny days and in ponds with high plankton bloom, the surface layer of ponds become warmer and lighter while the cooler-denser water forms a layer underneath. • Photosynthesis in deeper areas of the pond is reduced due to self-shading of planktons. • The already low oxygen levels are further reduced through decomposition of waste products, which settle to the pond bottom. • Mixing of more oxygenated surface water with low oxygen at pond bottoms is prevented because of the different densities between the two layers of water. • Dissolved oxygen depletion poses a very real problem to the fish farmer if supplemental aeration is not available.

44. 3) Dissolved oxygen (DO) Earth’s atmosphere = 200,000 mg/L H2O oxygen (saturated) = ~10 mg/L or < H2O oxygen (super-saturated)= ~30 mg/L Conclusion: O2 in water < O2 atmosphere

45. DO > 5 mg/L (atleast) • DO < 2.0 mg/L • Fish starts to gulp at the surface

46. What is DO The amount of oxygen dissolved in water, expressed in mg/L or ppm Measures the amount of oxygen in water that is available for respiration by aquatic organisms.

47. Dissolved Oxygen • Oxygen enters an aquatic system through: • Diffusion (resapan) – naturally (wind-aided) or through aeration • Photosynthesis • Entry of new water (inflow, runoff) • Rain

48. Atmospheric O2 enters to water through diffusion • O2 move from region of high conc. (air) to region of low conc. (water) • Faster through wind (water circulation) - Why?

49. Dissolved Oxygen (DO) • Dissolved oxygen (DO) is by far, the most important water quality parameter in aquaculture. • Like humans, fish require oxygen for respiration, survival and growth. • Oxygen consumption and DO requirement by fish increase with temperature and food consumption

50. Dissolved Oxygen • Biological processes that influence DO concentration in aquaculture ponds are: • Photosynthesis by green plants • Respiration by all aquatic animals