Vs. Aquaculture

1. Vs. Aquaculture Live or Prepared Feeds

2. Man-made... • Pellets or flakes. • Dry pellets the norm (uniform nutrition.) • Disadvantages: rapid sinking, unless extruded. • Semi-moist pellets: soft, high quality. • Disadvantage: expensive!! difficult to store in bulk.

3. What do we use?? • Manufactured fish feeds are made from a variety of ingredients: fish meal being the main one! • Alternatives are always welcome. • Many times it is easier to buy off the shelf. • What if you’re fish are unique, or won’t eat man made diets, or they just can’t?!

4. What is common here? • Small size • Incomplete development • Lack of digestive ability! Images of a tautog as it develops

6. Feeding Larval Fish: Plankton Culture

7. Phytoplankton Production • Feeding Larval Fish • Cell Size 4-8 microns • Species • Isochrysis galbana • Chaetoceros gracilis • Nannochloris sp. • Chlorella sp. • Pavlova lutheri

8. 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

9. 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 - 28°C • Culture media • Guillards f/2 • Proximate Analysis • 47% Protein • 24% Carbs • 17% Fat

10. 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 - 30°C • Culture media • Guillards f/2 with Si • Proximate Analysis • 28% Protein • 23% Carbs • 9% Fat

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

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

13. 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

14. Micro Algae Culture • Culture Water • Sterilization • Nutrient Enrichment • Inoculation • Cell Counts • Harvest and Feeding • Stock Culture

15. Culture Water • Sources • Seawater • Saltwater wells • Prepared seawater • Salinity • 26-32 ppt

16. 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

17. Nutrient Enrichment • Guillard’s f/2 • Part A and B • 0.5 ml/L each part • Na2Si03 for diatoms

18. 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

19. 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 Cell Counts Motile cells should be killed

20. Algae Density Wk 1 = 50,000 cells/ml Wk 2+ = 100,000 cells/ml Onset of spatting = 200,000/ml Tank cleared in 24hrs Larvae Density 5-10 larvae/ml Harvest and Feeding 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)

21. 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

22. Marine Fish Larval Culture • Relies on zooplankton

23. Marine Rotifer Brachionus plicatilis • Culture units • 40L plastic bags • 40L cone-bottomed tanks • Temperature 27-30 C • Salinity 26 ppt

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

25. Feeding Marine Fish • Rotifers • Typical first food in hatchery • Feed algae or yeast • Enrichment needed

26. Artemia • Feeding of older larvae

27. Artemia Preparation • Brine shrimp eggs/cysts are used globally as a food for small fish. • Eggs/cysts: dry=dormant for years!! • Cysts can be used unhatched, but it’s risky. • Can kill small fish.

28. Decapsulation • Sometimes decapsulation is needed (remove shell): chlorine (household bleach), leaving the unhatched baby brine shrimp protected in a membrane. • Besides making the harvest of the hatched brine shrimp easier, this process also: -sterilizes the eggs -higher percentage of hatching -feed unhatched eggs to fish -decapsulated eggs can be hatched later (stored in the refrigorator)

29. Equipment • A 3-gallon container with clear sides • 1 pound of brine shrimp eggs • 1 gallon of non-fragranced household bleach (5% chlorine) • Brine shrimp net or filter • Saturated brine solution*

30. Procedure • Soak 1 pound of eggs in 1 gallon of fresh water for 1 hour gently aerating the eggs. • After soaking, add 1 gallon of non-fragranced liquid household beach (5% chlorine) and reduce aeration. • Wait till eggs turn orange. • Strain contents through a brine shrimp net (or filter), and rinse in fresh water. • Store in saline solution for up to a month.

31. Use of copepods...

33. Larval rearing systems are often labor intensive. • Skilled workers are needed to maintain larval food culture. • Sometimes special equipment or systems are needed for small fish.