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Www.whatiftechnologies.com Food Nutrient Dynamics Model for Pond Aquaculture A seminar presented at Centre for Nutrition Modelling Department of Animal.

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Presentation on theme: "Www.whatiftechnologies.com Food Nutrient Dynamics Model for Pond Aquaculture A seminar presented at Centre for Nutrition Modelling Department of Animal."— Presentation transcript:

1 Food Nutrient Dynamics Model for Pond Aquaculture A seminar presented at Centre for Nutrition Modelling Department of Animal and Poultry Science University of Guelph, Guelph, Ontario Oct. 13, 2005 By Dr. Lanhai Li whatIf? Technologies Inc. Ottawa

2 Related Research Experience 4 Fish Bioenergetics modeling 4 Aquaculture pond dynamics 4 Hydrodynamics and Eutrophication process Modeling 4 Aquaculture Research Priorities Survey & Analysis in Asia and Pacific 4 Demographic dynamics

3 Outline of the Presentation 4 Introduction 4 Objectives 4 Methodologies 4 Model construction 4 Results 4 Conclusions

4 Introduction 4 Aquaculture: Promising Industry 4 Aquatic products: 25% of human protein consumption (Johnson and Associate, 1998) 4 32% of aquatic production from aquaculture Total aquatic products increased about 38.6% Aquaculture production increased 299.1% (FAO Statistics)

5 Introduction 4 Successful management of Pond Aquaculture –Constant supply of necessary nutrients Organic and inorganic –Balanced diets 4 Feeding strategies –No fertilizer or feed input –Fertilization –Supplementary feeding –Complete diet feeding

6 Problem 4 Complete diet feeding: –Supply of necessary food nutrients: Energy, Protein etc. –Cost: 50% of total operating cost 4 Alternatives: –Fertilization –Supplementary Feeding 4 Problem: –Lack of an insight view on the food nutrient dynamics (including quality and quantity) of aquacultural ponds

7 Objectives  To examine the impacts of fertilization strategies on food nutrient dynamics  To determine qualitative and quantitative requirements for food nutrients from supplementary feed

8 Process of food nutrient dynamics in an aquacultural pond

9 Methodology 4 System Dynamics Principles 4 Feedback and Loops 4 Dynamic Hypothesis

10 Food production feedback loops

11 Fish growth in a fertilized pond

12 Fish growth in a fertilized pond with supplementary feeding

13 Nitrogen feedback loops

14 Feedback loops for DO

15 Mathematical Equations 4 State variables 4 Rate variables 4 Auxiliary variables 4 Parameters 4 Based on mass balance Y t -Y t-  t =  t * (inflow t – outflow t )

16 Mathematical Equations –Autotrophic –Heterotrophic –Fish growth –Elementary Nutrients –DO

17 Field Experiment 1 4 Fertilization –Treatments: Low rate: 1 kg P/ha/day + 2 kg N/ha/day High rate: 2 kg P/ha/day + 4 kg N/ha/day –Three replicates –Fertilization once a week –At Bangkok from Jun 6 th to Sept 1 st, 1994 –Pond size: 200 m 2 area * 100 cm depth –Species: Nile Tilapia: all male monoculture with 3 fish per m 2

18 Field Experiment 2 Fertilization + supplementation –Treatments: Energy supplements (Cassava Starch) Energy + protein supplement (25% Protein) With 2 kg P/ha/day + 4 kg N/ha/day –Three replicates –Fertilization once a week –At Bangkok from Nov. 28 th 1994 to Mar 24 th 1995 –Pond size: 200 m 2 area * 100 cm depth –Species: Nile Tilapia: all male monoculture with 4 fish per m 2 –Feeding rate: 3% of fish body weight

19 Simulation 4 Original model was developed by STELLA

20 Results: Fertilization Experiment --Elementary nutrients

21 Results: Fertilization Experiment Food Nutrients

22 Results: Fertilization Experiment --Food consumption

23 Results: Fertilization Experiment --Mean fish weight

24 Results: Fertilization + supplementation Experiment --Food Nutrients

25 Results: Fertilization + supplementation Experiment --Food consumption

26 Results: Fertilization + supplementation Experiment --Mean fish weight

27 Results: Fertilization + supplementation Experiment – feed requirement Feed Protein

28 Conclusion 4 Fertilization can improve elementary nutrient supply and increase food nutrient production and fish biomass 4 Supplementary feeding is necessary for further fish growth under fertilization 4 Energy Supplements is enough at initial stage, but later energy + protein supplements are necessary 4 Modeling as a powerful methodology

29 References Li Lanhai, Amararatne Yakupitiyage and Khalid Saeed, 1998, Food nutrient dynamics model for fertilized ponds. System Dynamics: An International Journal of Policy Modeling. Vol. X, Nos. 1 & 2, pp L. Li and A. Yakupitiyage, A Model for Food Nutrient Dynamics of Semi-intensive pond Fish Culture. Aquacultural Engineering 27 (2003) *** 4 *** This paper was granted as Superior Paper Award by the Aquaculture Engineering Society in 2005

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