Tilapia. Tilapia have been introduced into more than 90 countries on all the continents except Antarctica

Transcription

1 Tilapia Tilapia have been introduced into more than 90 countries on all the continents except Antarctica * tilapia second most important fish in aquaculture American Tilapia Association -

2 * tilapia second most important fish in aquaculture Tilapia = 2,798,000 mt Catfish = 2,781,000 mt Tilapia aquaculture Production Subsistence 2,798,000 mt?

3 Advantages of tilapia Grow over a wide temperature range Classified as a tropical species with respect to temperature. Maximum growth occurs ~ 30 o C. Feeding activity is reduced below 20 o C and stops ~ 16 o C. The lethal lower temperature is ~ 10 o C.

4 Advantages of tilapia (cont.) Grow in a wide variety of water conditions Salinity from freshwater to seawater Acidic (ph 5) to alkaline (ph 9) Survive low DO and high ammonia High densities Prolific Mouthbrooders parental care Relatively large eggs removed young can be fed on powdered feed Female will resume breeding Sex reversal all male

5 Advantages of tilapia (cont.) Feed low on the food chain; typically omnivorous In low input systems, fish gain all their nutrition from algae, detrital matter or small invertebrates Intensification is relatively easy as they will also feed readily on formulated rations Tilapia profile from Agricultural Marketing Resource Center see: products/aquaculture/tilapia_profile.cfm#

6 Tilapia Production in Bangladesh Gupta et al Bangladesh - fish = 60 70% of animal protein Per cap. cons. = 7.9 kg/yr Urban elite = 22.1 kg/yr Rural poor = 4.4 kg/yr

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8 Light Carbon dioxide Appropriate temperature

9 Nutrients Appropriate salinity Mixing

10 Careful regulation of algal density

11 Stocking recommendations 20,000 ha (2/m 2 ) Pond size ~ 150 m 2 3 5g fingerlings Reach table size in 3 4 months

12 Supplementary feeding Supplement feeds With kitchen and farm wastes Rice bran 3%/body weight/day

13 Tilapia Production in Bangladesh Gupta et al Prod./Farm Pond Size (m 2 ) Water Days Next Year T 25 kg (97g) % 90 % 18 kg C 15 $ F 21 kg (110g) % 68 % 14 kg C 16 $ M 19 kg (101g) % Rural poor = 4.4 kg/yr 47 % 12 kg C 15 $

14 Dr. Gupta s achievements in freshwater aquaculture have helped millions of rural farmers overcome severe poverty and nutritional deficiencies. Dr. Gupta developed low-cost technologies to increase fish yields and educated impoverished farmers, specifically women, in freshwater aquaculture practices. His efforts led to a significant rise in the consumption of fish a vital source of protein and vitamins in developing countries in Asia and Africa and more effective aquaculture research worldwide.

15 Tilapia production - monoculture Extensive pond culture food security for families in developing countries. Low stocking densities; relies on available natural food; low yields kg/ha Semi-intensive pond culture - small scale commercial production/ integrated agriculture Organic (i.e. manure, often from livestock place above or in close quarters to the pond) and inorganic (chemical) fertilization; supplemental feed ingredients (agricultural by-products such as rice bran) yields 1,000-4,000 kg/ha in ponds with manure + supplemental feed

16 Aquaculture limiting factors Seed Oxygen Limits to fertilization? Food Wastes

17 Intensification

18 Question: Why pay $ 100 (supplemental feeds) to $ 250/ton (complete feeds) plus shipping if you don t have too. Why do natural foods become limiting?

19 Limits to fertilization Rev. Pietro Angelo Secchi ( ), Director of the Vatican Observatory Elbow test

20 Secchi disk - notes The Secchi disk is simply a disk lowered into the water. The less algae in the water the further it can be seen before disappearing. As algal concentrations increase, Secchi disk readings decrease. For example, in the next slide declining Secchi disk reading are shown over time with increasing algal levels in Lake Tahoe due to runoff containing fertilizer.

21 Secchi Disk

22 Relationship between Secchi disk readings, algal concentrations and DO The next figure (Fig. 3) shows how dissolved oxygen (D.O.) measured at dawn declines with decreasing Secchi disk readings (increasing turbidity of the water due to increasing concentrations of algae; in this case increasing amounts of feed serves as fertilizer to stimulate algal growth). In that algae like all plants produces oxygen as a byproduct of photosynthesis this may seem counter-intuitive at first. However, it must be remembered that photosynthesis and the subsequent production of oxygen only occurs during daylight hours. At night, algae as all living organisms will be consuming oxygen (see Fig. 4).

23 Figure 3. Effect of feeding rate on dissolved oxygen concentrations at dawn and Secchi disk visibility in ponds.

24 Decline of DO at night The low level of dissolved oxygen in the pond at dawn is because during the night (with no light energy) all pond organisms including the algae are respiring. In fact, the slope of the decline in dissolved oxygen (see Fig. 4) will be directly proportional to the biomass (strongly influenced by the biomass of the algae) in the pond.

25 Figure 4. Graphical representation of a procedure for predicting the nighttime decline in dissolved oxygen in a pond.

26 In spite of the fact that high concentrations of algae produce large amounts of oxygen during the day, the declines in D.O. are acerbated by high algal concentrations (see Figure 5.) Why is this? Figure 5. Effect of time of day and plankton density on concentrations of dissolved oxygen in surface water.

27 High algal concentrations lead tgo shading with depth The answer lies in the phenomena of selfshading. High concentrations of algae limit light penetration into the water column. Thus, while high levels of D.O. are found at the surface, these decline rapidly with depth where no photosynthesis is occurring (see Figure 6). This leads to a deficit of input of D.O. during the day relative to that used at night.

28 Figure 6. Influence of depth on dissolved oxygen concentrations in ponds with different amount of plankton. A similar deficit can be induced by overcast conditions following periods of rapid algal growth (see Figure 7.)

29 Figure 7. Effect of cloudy weather on dissolved oxygen concentration in a pond.

30 Algal crash If D.O. is allowed to decline to levels that won t support life (see Figure 8.), the pond will crash resulting in the death of all organisms in the pond. Immediately, following a crash the water is clear (see Figure 9.) in that all the dead algae sinks to the bottom providing a shroud over the aquaculturists crop.

31 Figure 8. Dissolved oxygen concentrations before, during, and after a massive phytoplankton die-off in a pond.

32 Figure 9. Changes in phytoplankton abundance before, during, and after a massive phytoplankton die-off in a pond. Note: somewhere in the pond a few algal cells will survive and restart the phytoplankton bloom. Unfortunately, this is not true of the aqauculturists crop.

33 Managing warm-water and tropical aquaculture ponds It is challenging to completely control the input of algal nutrients. This is particularly true if the aquaculture crop is being fed a diet in addition to pond fertilization. Uneaten feed as well as fish or shrimp wastes serves as fertilizer for algae (see Figure 10 and Figure 11).

34 Note: 40% (in the case of phosphorous) 55% (in the case of nitrogen) of feed nutrients are lost to the water. Figure 10. Waste production by aquatic animals.

35 Figure 11. Effect of feeding at three rates on dissolved oxygen concentrations at dawn in ponds.

36 Sound management practices Keep careful records of Secchi disk levels (maintain > 20 cm) and if possible D.O. levels to anticipate the necessity of management changes such as water exchange to reduce algal concentrations. As a.m. levels begin to drop, measurements of D.O. should also be made during the night to anticipate severity of nighttime decline. Stop inputs into ponds to decrease fertilization and/or feeding. The downside may be reduced growth of the aquaculture crop. Use aeration equipment. This maybe permanently located in the pond or available for emergency operation. Harvest crop early. While the crop may not be at an optimal size for the market, this strategy may be preferable to losing the entire crop.

37 Dynamics of pond aquaculture edited by Hillary S. Egna and Claude E. Boyd CRC Press, Boca Raton, Fl., 437 pp. $ 90 on Amazon.com Pond Aquaculture & Water Quality Management edited by Claude E. Boyd, and Craig S. Tucker Kluwer Academic, Boston, MA., 700 pp. $ 225 on Amazon.com

38 TFST TILAPIA FARMING SUPPORT TOOL Policy advice for sustainable fisheries (PASF) simulates: Mixed or mono-culture of Tilapia, with a local or a GIFT strain. It is extended for the poly culture with predators such as the African Catfish and the African Snakehead Further TFST provides basic economic/financial results, depending on the financial parameters you provided It provides the optimal rearing system after you have entered your own data

39 Tilapia Intensive Monoculture Intensive production with increasing levels of input, aeration and water exchange Nutritionally complete pelleted diet; routine aeration and partial water exchange; yields > 200 mt/ha/yr

40 $392,978,298 (2005) (2009) $482,742,515 (2006), $559,788,809 (2007), $734,450,306 (2008) 696,085,981 Value of Tilapia product forms imported to the Value of Tilapia product forms imported to the U.S.U.S $800,000,000 $200,000,000 $180,000,000 $700,000,000 $160,000,000 $600,000,000 $140,000,000 $120,000,000 $500,000,000 $100,000,000 $400,000,000 $80,000,000 $60,000,000 $300,000,000 $40,000,000 Whole Frozen Fillet Frozen $20,000,000 $200,000,000 Fillet Fresh $0 $100,000, Whole Frozen Fillet Frozen $ $ US $ US Fillet Fresh

41 High quality fresh and frozen fillets Hand trimming of fillets Buyers are requesting better trim of margins of fillets for more consistent appearance

42 If the U.S. producers focus on the live market, who produces all the rest?

43 2009 U.S. tilapia imports (x 1,000,000 lbs) All forms China Taiwan Ecuador Indonesia Honduras Costa Rica Thailand Others Total

44 2009 U.S. tilapia imports fillets, fresh (x 1,000,000 lbs) Ecuador 20 Honduras 14 Costa Rica 13 Columbia 4 Others 3 Total 54 Rain Forest Aquaculture, Costa Rica see

45 2009 U.S. tilapia imports fillets, frozen (x 1,000,000 lbs) China 222 Indonesia 11 Taiwan 5 Ecuador 2 Others 4 Total 253 Izumi-Dai IQF fillets, China

46 Guess where (most likely country) these frozen fillets were produced? Guess what part of the world most likely produced these fresh fillets?

47 Next meeting of the ATA will be held in conjunction with WAS Aquaculture America 2011 February 28 March 3, 2011 New Orleans, Louisiana Student membership with publications $ 65.00/year