D. V. Robertson-Andersson; A. Govender; T. Probyn; C. Halling; M. Troell; J. Bolton & R. Anderson CULTIVATION OF ULVA IN A...
INTRODUCTION <ul><li>Previous studies in Israel here have shown that  Ulva lactuca  is capable of removing significant amo...
Benefits of a closed system <ul><li>Increase in temperature above ambient seawater equates to an increase in growth rates ...
Why cultivate seaweeds on abalone farms? <ul><li>Mixed diet gives better growth rates  </li></ul><ul><li>MSY of kelp bed r...
AIMS 2000 - 2003  <ul><li>1) F easibility of growing commercially useful amounts of  Gracilaria  and  Ulva   </li></ul><ul...
AIMS 2004 - 2006 <ul><li>Investigate and model the physico-chemical dynamics of a farm section </li></ul><ul><li>Influence...
PROJECT SITES <ul><li>A balone mariculture farms </li></ul><ul><li>Danger Point  (I & J Mariculture Farm)  +   140 km east...
0 1 2 3 4 5 6 7 8 sea shaded sea fert shaded fert abalone shaded abalone SGR % day  -1 J  J  A  S  O  N  D  J  F  M  A  M ...
RESULTS RGR of  Ulva  from June ‘01 to October ‘02 in sea, Turbot & abalone effluent water at JSP.
RESULTS Myrionema strangulans  (MS) <ul><li>Brown spots </li></ul><ul><li>Numbering between 5 and 10 on the holdfast secti...
RESULTS Myrionema strangulans  (MS) BAD INFECTION DEAD HEALTHY INFECTED
RESULTS MS infestation of  Ulva  thalli
RESULTS <ul><li>Are important because: </li></ul><ul><li>Low water exchange rate leads to: </li></ul><ul><ul><li>Carbon an...
RESULTS SHADING <ul><li>Important  because </li></ul><ul><li>Shading helps to reduce epiphytes </li></ul><ul><li>Helps in ...
RESULTS <ul><li>Important because: </li></ul><ul><li>Increases protein from wild harvest  (3.7- 24 % wild to 49.8 % cultur...
RESULTS Tissue Nitrogen vs. Thallus  Colour Tissue nitrogen vs. thallus colour
RESULTS Tissue Nitrogen vs. Tissue Phosphorus Tissue N vs. Tissue P A  S  O  N  D  J  F  M  A  M  J  J  A
PROJECT DESIGN AT I & J 2004 <ul><li>2  Ulva  tanks (5 X 1 X 0.63 m)  were integrated to one abalone tank (7 X 2 X 1 m) </...
Longitudinal profile of tanks Transverse profile of tanks 5 m 1 m
Longitudinal profile of tanks Transverse profile of tanks
Seaweed tank  Pump Gravity feed  Abalone tanks Seaweed tank  80 % recirculation  20 % Sea water  Over flow
RESULTS <ul><li>In this system :  </li></ul><ul><li>Ulva  can take up 90 % of ammonium during the day in abalone effluent ...
RESULTS <ul><li>Ammonium levels must remain below 0.15  u M N.L -1 </li></ul><ul><li>DO values between 2 and 12 mg.L -1 , ...
Balancing the equations Using linear mass balanced equations Multiple regression of factors Problems putting theory and re...
RESULTS Dissolved oxygen Dissolved oxygen in a recirculation system 15  16  20  00  04  08  12  16  20  00  04  08  12  16
RESULTS Dissolved oxygen Dissolved oxygen in a recirculation system 15  16  20  00  04  08  12  16  20  00  04  08  12  16
RESULTS pH in a recirculation system pH 15  16  20  00  04  08  12  16  20  00  04  08  12  16
RESULTS pH in a recirculation system pH 15  16  20  00  04  08  12  16  20  00  04  08  12  16
RESULTS Temperature in a recirculation system Temperature 15  16  20  00  04  08  12  16  20  00  04  08  12  16
RESULTS Temperature in a recirculation system Temperature 15  16  20  00  04  08  12  16  20  00  04  08  12  16
RESULTS ammonium levels in  recirculated tanks  range between 0.003 - 0.005  u M N ammonium levels in  abalone flow throug...
Major Challenges <ul><li>For farm management of such a system: </li></ul><ul><li>Diel relationship between oxygen and pH i...
The future <ul><li>Run this study over a 18 months to obtain seasonal changes  </li></ul><ul><li>Effect of diet on growth ...
  THANK YOU ACKNOWLEDGEMENTS I would like to extend special thanks to the following people and organizations without whose...
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CULTIVATION OF ULVA IN AQUACULTURE EFFLUENT A preliminary investigation

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This presentation was given to the concil members of the recirculation council for Southern Africa in 2004. It lists reasons why Ulva is a good candidate for cultivation in aquaculture effluent.

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CULTIVATION OF ULVA IN AQUACULTURE EFFLUENT A preliminary investigation

  1. 1. D. V. Robertson-Andersson; A. Govender; T. Probyn; C. Halling; M. Troell; J. Bolton & R. Anderson CULTIVATION OF ULVA IN AQUACULTURE EFFLUENT A preliminary investigation Recirculation Council Meeting 2004
  2. 2. INTRODUCTION <ul><li>Previous studies in Israel here have shown that Ulva lactuca is capable of removing significant amounts of nutrients (60 – 85%) from aquaculture effluents </li></ul><ul><li>Modelling these systems is built on vertical integration (i.e. not closed systems) </li></ul><ul><li>Models of such systems use whole farm approaches </li></ul>
  3. 3. Benefits of a closed system <ul><li>Increase in temperature above ambient seawater equates to an increase in growth rates </li></ul><ul><li>Decrease in pumping costs </li></ul><ul><li>Additional safety in times of red tide and oil spills </li></ul>
  4. 4. Why cultivate seaweeds on abalone farms? <ul><li>Mixed diet gives better growth rates </li></ul><ul><li>MSY of kelp bed reached in 2002 </li></ul><ul><ul><li>Potential over-harvesting </li></ul></ul><ul><ul><li>Decrease in epiphyte densities </li></ul></ul><ul><li>Limited suitable coastal areas </li></ul><ul><li>‘ HAB’s’ </li></ul><ul><li>Recirculation </li></ul><ul><li>I ntegration will improve water quality </li></ul>
  5. 5. AIMS 2000 - 2003 <ul><li>1) F easibility of growing commercially useful amounts of Gracilaria and Ulva </li></ul><ul><li>Influence of different growth media (seawater, abalone and turbot effluent water and fertilized seawater) on growth rates and yields. </li></ul><ul><li>Seasonal changes in tissue N and P content </li></ul><ul><li>Relationships between stocking density and yield </li></ul><ul><li>Uptake rates of various nutrients at differing stocking densities </li></ul>
  6. 6. AIMS 2004 - 2006 <ul><li>Investigate and model the physico-chemical dynamics of a farm section </li></ul><ul><li>Influence of different diet on abalone growth health and excretion rates in a closed system compared to a flow through system </li></ul><ul><li>Seasonal changes in the above </li></ul><ul><li>System environmental quality </li></ul>
  7. 7. PROJECT SITES <ul><li>A balone mariculture farms </li></ul><ul><li>Danger Point (I & J Mariculture Farm) + 140 km east of CT </li></ul><ul><li>Jacobs Baai (Jacobs Baai Sea Products) + 120 km N of CT </li></ul>
  8. 8. 0 1 2 3 4 5 6 7 8 sea shaded sea fert shaded fert abalone shaded abalone SGR % day -1 J J A S O N D J F M A M J J A S O RESULTS OF 2000 - 2003 SGR of Ulva from June ‘01 to October ‘02 in sea, fertilized & abalone effluent water. (2) where water exchanges increased at I & J 2
  9. 9. RESULTS RGR of Ulva from June ‘01 to October ‘02 in sea, Turbot & abalone effluent water at JSP.
  10. 10. RESULTS Myrionema strangulans (MS) <ul><li>Brown spots </li></ul><ul><li>Numbering between 5 and 10 on the holdfast section of Ulva thalli </li></ul><ul><li>The spots are regular discs, 1 – 3 mm in diameter </li></ul><ul><li>First record for South Africa </li></ul><ul><li>Identified by Dr. Herre Stegenga </li></ul><ul><li>Negative correlation between infection density and SGR </li></ul>
  11. 11. RESULTS Myrionema strangulans (MS) BAD INFECTION DEAD HEALTHY INFECTED
  12. 12. RESULTS MS infestation of Ulva thalli
  13. 13. RESULTS <ul><li>Are important because: </li></ul><ul><li>Low water exchange rate leads to: </li></ul><ul><ul><li>Carbon and nutrient limitation </li></ul></ul><ul><ul><li>Poor condition of thalli (bleached & broken) </li></ul></ul><ul><ul><li>Low Nitrogen content </li></ul></ul><ul><ul><li>Low SGR </li></ul></ul><ul><li>therefore low yield </li></ul><ul><li>Measures </li></ul><ul><li>Carbon limitation in seaweeds can be shown by an increase in pH values </li></ul>FLOW RATES (4, 12 & 20)
  14. 14. RESULTS SHADING <ul><li>Important because </li></ul><ul><li>Shading helps to reduce epiphytes </li></ul><ul><li>Helps in decreasing MS infestations </li></ul><ul><li>Helps to increase tissue N and P </li></ul><ul><li>How? </li></ul><ul><li>Tanks should be shaded from September to January </li></ul><ul><li>Shade cloth must be 20 % not 50 % </li></ul>
  15. 15. RESULTS <ul><li>Important because: </li></ul><ul><li>Increases protein from wild harvest (3.7- 24 % wild to 49.8 % cultured) </li></ul><ul><li>Abalone receive more protein </li></ul><ul><li>Faster growth rates </li></ul><ul><li>How do you increase tissue nutrients? </li></ul><ul><li>Faster flow rates (12 – 20 volume exchanges) </li></ul><ul><li>Grown in turbot/fish or abalone effluent </li></ul><ul><li>Add Fertilizer and Kelpak® </li></ul>Tissue Nitrogen
  16. 16. RESULTS Tissue Nitrogen vs. Thallus Colour Tissue nitrogen vs. thallus colour
  17. 17. RESULTS Tissue Nitrogen vs. Tissue Phosphorus Tissue N vs. Tissue P A S O N D J F M A M J J A
  18. 18. PROJECT DESIGN AT I & J 2004 <ul><li>2 Ulva tanks (5 X 1 X 0.63 m) were integrated to one abalone tank (7 X 2 X 1 m) </li></ul><ul><li>Run under normal farm operating conditions </li></ul><ul><li>Control are 3 flow through abalone tanks </li></ul><ul><li>Seaweeds initial stocking density 2.5 kg.m -2 </li></ul><ul><li>Harvested every two weeks </li></ul><ul><li>+ 13 200 abalone (10 – 15g), total biomass 165 kg </li></ul><ul><ul><li>20 % fresh seawater input (800 L.h -1 ) </li></ul></ul><ul><ul><li>80 % recirculated through seaweeds (3 200 L.h -1 ) </li></ul></ul>
  19. 19. Longitudinal profile of tanks Transverse profile of tanks 5 m 1 m
  20. 20. Longitudinal profile of tanks Transverse profile of tanks
  21. 21. Seaweed tank Pump Gravity feed Abalone tanks Seaweed tank 80 % recirculation 20 % Sea water Over flow
  22. 22. RESULTS <ul><li>In this system : </li></ul><ul><li>Ulva can take up 90 % of ammonium during the day in abalone effluent at 12 volume exchanges per day </li></ul><ul><li>DO values don’t go below 9 mg.l -1 at night </li></ul><ul><li>Using stocking density of 3 kg. wwt.m -2 gives best uptake rates in the existing system </li></ul><ul><li>Toxic ammonia never reaches levels harmful to abalone at above stocking density </li></ul>Seaweed uptake
  23. 23. RESULTS <ul><li>Ammonium levels must remain below 0.15 u M N.L -1 </li></ul><ul><li>DO values between 2 and 12 mg.L -1 , preferred 4 - 9 </li></ul><ul><li>Temperature range 9 – 22 °C, 16 – 18 °C preferred </li></ul><ul><li>pH 6.5 – 8.4, 7.6 - 8.2 preferred </li></ul>Abalone critical points
  24. 24. Balancing the equations Using linear mass balanced equations Multiple regression of factors Problems putting theory and reality together
  25. 25. RESULTS Dissolved oxygen Dissolved oxygen in a recirculation system 15 16 20 00 04 08 12 16 20 00 04 08 12 16
  26. 26. RESULTS Dissolved oxygen Dissolved oxygen in a recirculation system 15 16 20 00 04 08 12 16 20 00 04 08 12 16
  27. 27. RESULTS pH in a recirculation system pH 15 16 20 00 04 08 12 16 20 00 04 08 12 16
  28. 28. RESULTS pH in a recirculation system pH 15 16 20 00 04 08 12 16 20 00 04 08 12 16
  29. 29. RESULTS Temperature in a recirculation system Temperature 15 16 20 00 04 08 12 16 20 00 04 08 12 16
  30. 30. RESULTS Temperature in a recirculation system Temperature 15 16 20 00 04 08 12 16 20 00 04 08 12 16
  31. 31. RESULTS ammonium levels in recirculated tanks range between 0.003 - 0.005 u M N ammonium levels in abalone flow through tanks = 0.01 u M N Ammonium levels
  32. 32. Major Challenges <ul><li>For farm management of such a system: </li></ul><ul><li>Diel relationship between oxygen and pH in the seaweed systems. </li></ul><ul><li>As the seaweeds start to respire at night, abalone experience an increase in oxygen demand, due to night time feeding activity and excretion in the abalone systems, which has implications for the management of ammonia. </li></ul><ul><li>Seaweed uptake decreases at night when abalone excretion reaches a maximum </li></ul><ul><li>Where is the missing oxygen? </li></ul>
  33. 33. The future <ul><li>Run this study over a 18 months to obtain seasonal changes </li></ul><ul><li>Effect of diet on growth and health </li></ul><ul><li>Health of abalone in an integrated closed system vs. normal farm flow through conditions </li></ul>
  34. 34.   THANK YOU ACKNOWLEDGEMENTS I would like to extend special thanks to the following people and organizations without whose help this project would be impossible: I & J Mariculture farm particularly N. Loubser, H. Otto and L. Ansara JSP Mariculture farm particularly K. Ruck N R F Swedish and South African Collaborative Program Kelp Products JSP

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