Plankton Culture for Feeding Larval Fish and Shellfish

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Plankton Culture for Feeding Larval Fish and
Shellfish

• LaDon Swann
• Mississippi-Alabama Sea Grant Consortium
• Auburn University

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Shellfish Larval Culture
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Larval Rearing

• Trocophore
• Size 50-60 microns
• 6-12 hours post-fertilization
• D-Hinge or Straight Hinge
• Size 70-80 microns
• 24-48 hours post-fertilization
• Bivalve Shell
• Velum - Swimming and Feeding organ

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Larval Rearing

• Veliger or Umbo Larvae
• Size 80-300 microns
• Stage last 8-12 days
• Well defined umbo
• Pediveliger or Eyed Larvae
• Size gt300 microns
• Pigmented eye-spot
• Muscular foot

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Phytoplankton Production

• Feeding Larvae
• Cell Size 4-8 microns
• Species
• Isochrysis galbana
• Chaetoceros gracilis
• Nannochloris sp.
• Chlorella sp.
• Pavlova lutheri

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Pavlova lutheri

• Morphology
• Golden brown
• Spherical with 2 flagella
• 3-6 µm
• Salinity
• 8-32 ppt
• Temperature
• 11-26 C
• Culture media
• Guillards f/2
• Proximate Analysis
• 52 Protein
• 24 Carbs
• 29 Fat

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Isochrysis galbana

• Morphology
• Tahiti (T-Iso strain)
• Golden brown
• Cells spherical with 2 flagella
• 5-6 µm length, 2-4 µm wide
• Salinity
• 8-32 ppt
• Temperature
• 23 - 28C
• Culture media
• Guillards f/2
• Proximate Analysis
• 47 Protein
• 24 Carbs
• 17 Fat

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Chaetoceros gracilis

• Morphology
• Golden brown diatom
• Medium-size 12 µm wide, 10.5 µm long
• Cells united in chains
• Salinity
• 26 - 32 ppt
• Temperature
• 28 - 30C
• Culture media
• Guillards f/2 with Si
• Proximate Analysis
• 28 Protein
• 23 Carbs
• 9 Fat

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Plankton for Shellfish

• Broodstock and Spat
• Cell Size 10-24 microns
• Species
• Tetraselmis sp.
• Green
• Thalassiosra sp.
• Diatom

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Tetraselmis sp.

• Morphology
• Ovoid green cells
• 14 to 23 µm L X 8 µm W
• 4 flagella
• Salinity
• 28-36 ppt
• Temperature
• 22-26C
• Culture media
• Guillards f/2
• Proximate Analysis
• 55 Protein
• 18 Carbs
• 14 Fat

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Thalassiosra sp.

• Morphology
• Golden brown diatom
• Cells united in chains
• Barrel-shaped
• Non-motile
• 4 µm
• Salinity
• 26 32 ppt
• Temperature
• 22-29 C
• Culture media
• Guillards f/2 with Si
• Other characteristics

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Micro Algae Culture

• Culture Water
• Sterilization
• Nutrient Enrichment
• Inoculation
• Cell Counts
• Harvest and Feeding
• Stock Culture

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Culture Water

• Sources
• Seawater
• Saltwater wells
• Prepared seawater
• Salinity
• 26-32 ppt

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Sterilization

• Methods
• Heat Pasteurization
• 80 C and cool naturally
• Autoclave
• Sodium Hypochlorite (bleach)
• 0.5 ml/L (10 drops)
• Neutralize 10-15 ml sodium thiosulfate (248 g/L)
  per liter
• Hydrochloric acid (muriatic)
• 0.2 ml/L (4 drops)
• Neutralize Na2CO3 0.4-0.9 g/L

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Nutrient Enrichment

• Guillards f/2
• Part A and B
• 0.5 ml/L each part
• Na2Si03 for diatoms

Nutrients Conc.(mg/l Seawater)
NaNO3 75
NaH2PO4.H2O 5
Na2SiO3.9H2O 30
Na2C10H14O8N2.H2O (Na2EDTA) 4.36
CoCl2.6H2O 0.01
CuSO4.5H2O 0.01
FeCl3.6H2O 3.15
MnCl2.4H2O 0.18
Na2MoO4.2H2O 0.006
ZnSO4.7H2O 0.022
Thiamin HCl 0.1
Biotin 0.0005
B12 0.0005
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Inoculation

• Culture vessels
• 1,000 ml flask
• 18.7 L (5 gal.) Carboy (glass)
• 178 L (47 gal) Transparent Tank
• Add enough algae to give a strong tint to the
  water
• 100,000-200,000/ml
• Lighting
• Types
• Sunlight
• Fluorescent
• VHO fluorescent
• Metal halide
• Highest Densities 24/7

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Cell Counts

• Peak Algae Density
• I. Galbana
• 10-12 million cells/ml
• 10-14 days
• 2 wk stability
• T. pseudonana
• 4 million cells/ml
• 3 days
• 5 day stability

• Hemacytometer
• Count total in centermost 1 mm
• Multiply by 10,000
• Product number/ml

Motile cells should be killed
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Harvest and Feeding

• Larvae Density
• 5-10 larvae/ml

• Algae Density
• Wk 1 50,000 cells/ml
• Wk 2 100,000 cells/ml
• Onset of spatting 200,000/ml
• Tank cleared in 24hrs

Liters to feed (TD x V)/CD TD Target
Density (1,000s/ml) V Volume of larval tank
(thousands of L) CD Cell Density
(millions/ml)
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Harvesting and Feeding

• Batch
• Total harvest occurs once or over several days
• Semi-Continuous
• Works well with diatoms
• Part of the algae remains in the vessel
• New media is added to replenish the algae removed

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Stock Culture

• Purchase pure strain
• Avoid contamination
• No aeration
• Half filed container
• Redundancy
• Holding
• Test tubes
• Conical flasks
• Transfer
• 1 drop/wk for T. pseudonana
• 1 drop/2 wk for I. galbana

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Marine Fish Larval Culture

• Relies on zooplankton

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Marine Rotifer Brachionus plicatilis

• Culture units
• 40L plastic bags
• 40L cone-bottomed tanks
• Temperature 27-30 C
• Salinity 26 ppt

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Rotifers

• Laboratory production
• 100 to 200 mm size
• 2-3 week life span
• small size suitable as first food

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Feeding Marine Fish

• Rotifers
• Typical first food in hatchery
• Feed algae or yeast
• Enrichment needed

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Artemia

• Feeding of older larvae

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Use of copepods