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A pilot scale integrated seaweed (Ulva lactuca) & abalone (Haliotis midae) recirculation system

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1. A pilot scale integrated seaweed ( Ulva lactuca ) & abalone ( Haliotis midae ) recirculation system Deborah V. Robertson-Andersson 1,6 ; Michelle, Potgieter 1 ,…
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  • 1. A pilot scale integrated seaweed ( Ulva lactuca ) & abalone ( Haliotis midae ) recirculation system Deborah V. Robertson-Andersson 1,6 ; Michelle, Potgieter 1 , Joakim, Hansen 2 ; John J. Bolton 1 , Max Troell 2,3 , Robert J. Anderson 4 , Christina Halling 2 , Trevor Probyn 5 1 Botany Department, U CT 2 Department of Systems Ecology, Stockholm University 3 Beijer Institute, Stockholm, Sweden 4 Seaweed Research Unit, MCM 5 Aquaculture Unit, MCM 6 Biodiversity & Conservation Biology, UWC
  • 2. INTRODUCTION <ul><li>Previous studies in Israel and South Africa have shown that Ulva lactuca is capable of removing significant amounts of nutrients (60 – 85 %) from aquaculture effluents </li></ul><ul><ul><ul><li>These systems were built on vertical integration </li></ul></ul></ul><ul><ul><ul><li>They were generally open/ flow though systems </li></ul></ul></ul><ul><ul><ul><li>Often included fish as with a high waste production </li></ul></ul></ul>
  • 3. Advantages 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 due to reduced head heights </li></ul><ul><li>Additional safety in times of red tide and oil spills </li></ul><ul><li>Benefit of additional food source </li></ul>
  • 4. Disadvantages of a closed system <ul><ul><li>Excessive sediment build up. </li></ul></ul><ul><ul><li>Higher bacteria concentrations. </li></ul></ul><ul><ul><li>Reduction in water quality. </li></ul></ul><ul><ul><li>Increased occurrence of diseases or parasites. </li></ul></ul><ul><ul><li>Stress in abalone. </li></ul></ul><ul><ul><li>Decreased growth of abalone. </li></ul></ul><ul><ul><li>Changes in physico- chemical variables. </li></ul></ul>
  • 5. AIMS <ul><li>Investigate the physico-chemical dynamics. </li></ul><ul><li>Investigate sediment build up and composition. </li></ul><ul><li>Investigate growth rates of seaweeds and abalone. </li></ul><ul><li>Investigate disease, parasite and pest organisms. </li></ul><ul><li>Seasonal changes in the above. </li></ul><ul><li>Investigate water quality. </li></ul>Flow through vs. Recirculation system
  • 6. PROJECT DESIGN @ I & J <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 were 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 – 15 g) total starting biomass 165 kg. </li></ul><ul><ul><li>75 % fresh seawater input (3 200 L h -1 ). </li></ul></ul><ul><ul><li>25 % recirculated from seaweeds (800 L h -1 ). </li></ul></ul>
  • 7. Seaweed tank Pump Gravity feed Abalone tanks Seaweed tank 25 % recirculation 75 % Sea water Over flow
  • 8. Seaweed tank Pump Gravity feed Abalone tanks Seaweed tank 25 % recirculation 75 % Sea water Over flow
  • 9. RESULTS <ul><li>Abalone SGR </li></ul>
  • 10. RESULTS <ul><li>Ulva lactuca SGR </li></ul>
  • 11. RESULTS <ul><li>Myrionema strangulans Greville and Fissurella mutabilis Sow. </li></ul>
  • 12. RESULTS <ul><li>Ulva lactuca SGR vs. large scale environment </li></ul><ul><li>Advection </li></ul><ul><li>Upwelling </li></ul><ul><li>Warm water intrusion </li></ul>www.rsmarinesa.org.za
  • 13. RESULTS <ul><li>Ulva lactuca SGR vs. environment </li></ul>
  • 14. RESULTS <ul><li>Dissolved oxygen concentrations </li></ul><ul><li>There was a 33 % loss of oxygen from the seaweed tanks to the abalone tanks. </li></ul><ul><li>Dissolved oxygen in the abalone tanks flow through system was 4 % higher than those in the recirculation system. </li></ul>
  • 15. RESULTS <ul><li>Nutrient uptake </li></ul>0 PO 4 54.85 FAN 48.8 64.8 38.06 25 % Recirc. abalone vs. FTS abalone NO 2 NO 3 TAN % difference in nutrient uptake efficiency
  • 16. RESULTS <ul><li>Bottom sediment accumulation </li></ul>P < 0.01
  • 17. RESULTS <ul><li>Other Results </li></ul><ul><li>Sediments </li></ul><ul><li>Weekly accumulation </li></ul><ul><li>Water column </li></ul><ul><li>Bacteria </li></ul><ul><li>Vibrio ’s </li></ul><ul><li>Total bacteria </li></ul><ul><li>Abalone health </li></ul><ul><li>Sabellids </li></ul><ul><li>General condition </li></ul><ul><li>Internal parasites (Gut protozoa, Rickettsia ) </li></ul><ul><li>Gonad histology </li></ul>
  • 18. CONCLUSIONS <ul><li>There are no negative effects on abalone health or growth rates from being included in a 25 % Recirculation system </li></ul><ul><li>Benefits of such a system are </li></ul><ul><li>Decreased sediments in water column </li></ul><ul><li>Decreased Vibrio’s bacterial counts </li></ul><ul><li>Increased temperature </li></ul><ul><li>The ability to protect from external harmful influences </li></ul><ul><li>Negatives in this system </li></ul><ul><li>Low phosphate uptake </li></ul><ul><li>Low oxygen transfer </li></ul><ul><li>Greater temperature variation in winter </li></ul>
  • 19. SO what next…. <ul><li>You build a full scale system!!!! </li></ul>
  • 20. SO what next….
  • 21. Commercial integrated seaweed abalone system: 50 % recirculation Intake Seaweed paddle ponds Sump Drum filter Abalone tanks Header tank Pump Seaweed harvest point Outlet
  • 22. Feed Quality: Tissue Nitrogen vs. Thallus Colour Tissue protein content (mg N.g)
  • 23. Food Quality: Humans
  • 24. Food Quality: Humans Taste test questionnaire Dear taste tester Thank you for agreeing to be a part of this testing programme. Testing will be done using two taste test approaches: A) A quantitative descriptive analysis B) A difference test (triangle test) The purpose of this test is three fold: 1) To rank you as a tester 2) To evaluate which is the most acceptable abalone diet 3) To compare all the taste samples to a reference smell of DMS This will be done for both cooked and raw abalone.
  • 25. Food Quality: Humans Taste test questionnaire Dear taste tester Thank you for agreeing to be a part of this testing programme. Testing will be done using two taste test approaches: A) A quantitative descriptive analysis B) A difference test (triangle test) The purpose of this test is three fold: 1) To rank you as a tester 2) To evaluate which is the most acceptable abalone diet 3) To compare all the taste samples to a reference smell of DMS This will be done for both cooked and raw abalone.
  • 26. Food Quality: Humans
  • 27. <ul><li>Food quality changes with: </li></ul><ul><li>Tester category </li></ul><ul><li>UC - farmers : taste intensity, acceptability of texture </li></ul><ul><li>Asian : taste and odour characteristics </li></ul><ul><li>C - farmers : sweetness and odour freshness </li></ul><ul><li>Asian : bitterness, sourness </li></ul><ul><li>Sample preparation </li></ul><ul><li>UC -surface texture, colour, aroma intensity </li></ul><ul><li>C - surface texture, colour, visual and taste freshness, sweetness </li></ul><ul><li>Diet </li></ul><ul><li>UC - wild-caught vs. rest: odour intensity, colour; Ulva-fed vs. rest: texture (visual and touch) </li></ul><ul><li>C - separation more pronounced; each feed-type influenced by a different sensory variable </li></ul>Food Quality: Humans
  • 28. THANK YOU ACKNOWLEDGEMENTS I would like to extend special thanks to the following organizations without whose help this project would have been impossible: Swedish and South African Collaborative Program I & J Mariculture farm N R F SANCOR Frontier Program
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