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

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

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This is a presentation I gave at the Applied Phycology congress in Galway Ireland in the IMTA session in 2008

This is a presentation I gave at the Applied Phycology congress in Galway Ireland in the IMTA session in 2008

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

    • 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
    • INTRODUCTION
      • 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
          • These systems were built on vertical integration
          • They were generally open/ flow though systems
          • Often included fish as with a high waste production
    • Advantages of a closed system
      • Increase in temperature above ambient seawater equates to an increase in growth rates
      • Decrease in pumping costs due to reduced head heights
      • Additional safety in times of red tide and oil spills
      • Benefit of additional food source
    • Disadvantages of a closed system
        • Excessive sediment build up.
        • Higher bacteria concentrations.
        • Reduction in water quality.
        • Increased occurrence of diseases or parasites.
        • Stress in abalone.
        • Decreased growth of abalone.
        • Changes in physico- chemical variables.
    • AIMS
      • Investigate the physico-chemical dynamics.
      • Investigate sediment build up and composition.
      • Investigate growth rates of seaweeds and abalone.
      • Investigate disease, parasite and pest organisms.
      • Seasonal changes in the above.
      • Investigate water quality.
      Flow through vs. Recirculation system
    • PROJECT DESIGN @ I & J
      • 2 Ulva tanks (5 X 1 X 0.63 m) were integrated to one abalone tank (7 X 2 X 1 m).
      • Run under normal farm operating conditions.
      • Control were 3 flow through abalone tanks.
      • Seaweeds initial stocking density 2.5 kg m -2 .
      • Harvested every two weeks.
      • + 13 200 abalone (10 – 15 g) total starting biomass 165 kg.
        • 75 % fresh seawater input (3 200 L h -1 ).
        • 25 % recirculated from seaweeds (800 L h -1 ).
    • Seaweed tank Pump Gravity feed Abalone tanks Seaweed tank 25 % recirculation 75 % Sea water Over flow
    • Seaweed tank Pump Gravity feed Abalone tanks Seaweed tank 25 % recirculation 75 % Sea water Over flow
    • RESULTS
      • Abalone SGR
    • RESULTS
      • Ulva lactuca SGR
    • RESULTS
      • Myrionema strangulans Greville and Fissurella mutabilis Sow.
    • RESULTS
      • Ulva lactuca SGR vs. large scale environment
      • Advection
      • Upwelling
      • Warm water intrusion
      www.rsmarinesa.org.za
    • RESULTS
      • Ulva lactuca SGR vs. environment
    • RESULTS
      • Dissolved oxygen concentrations
      • There was a 33 % loss of oxygen from the seaweed tanks to the abalone tanks.
      • Dissolved oxygen in the abalone tanks flow through system was 4 % higher than those in the recirculation system.
    • RESULTS
      • Nutrient uptake
      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
    • RESULTS
      • Bottom sediment accumulation
      P < 0.01
    • RESULTS
      • Other Results
      • Sediments
      • Weekly accumulation
      • Water column
      • Bacteria
      • Vibrio ’s
      • Total bacteria
      • Abalone health
      • Sabellids
      • General condition
      • Internal parasites (Gut protozoa, Rickettsia )
      • Gonad histology
    • CONCLUSIONS
      • There are no negative effects on abalone health or growth rates from being included in a 25 % Recirculation system
      • Benefits of such a system are
      • Decreased sediments in water column
      • Decreased Vibrio’s bacterial counts
      • Increased temperature
      • The ability to protect from external harmful influences
      • Negatives in this system
      • Low phosphate uptake
      • Low oxygen transfer
      • Greater temperature variation in winter
    • SO what next….
      • You build a full scale system!!!!
    • SO what next….
    • Commercial integrated seaweed abalone system: 50 % recirculation Intake Seaweed paddle ponds Sump Drum filter Abalone tanks Header tank Pump Seaweed harvest point Outlet
    • Feed Quality: Tissue Nitrogen vs. Thallus Colour Tissue protein content (mg N.g)
    • Food Quality: Humans
    • 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.
    • 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.
    • Food Quality: Humans
      • Food quality changes with:
      • Tester category
      • UC - farmers : taste intensity, acceptability of texture
      • Asian : taste and odour characteristics
      • C - farmers : sweetness and odour freshness
      • Asian : bitterness, sourness
      • Sample preparation
      • UC -surface texture, colour, aroma intensity
      • C - surface texture, colour, visual and taste freshness, sweetness
      • Diet
      • UC - wild-caught vs. rest: odour intensity, colour; Ulva-fed vs. rest: texture (visual and touch)
      • C - separation more pronounced; each feed-type influenced by a different sensory variable
      Food Quality: Humans
    • 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