Vs. Aquaculture

Live or Prepared Feeds

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.

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?!

What is common here?

• Small size• Incomplete

development• Lack of digestive

ability!

Images of a tautog as it develops

Feeding Larval Fish:Feeding Larval Fish: Plankton Culture Plankton Culture

Phytoplankton Production

• Feeding Larval Fish– Cell Size 4-8 microns– Species

• Isochrysis galbana• Chaetoceros gracilis• Nannochloris sp.• Chlorella sp.• Pavlova lutheri

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

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

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

Plankton for Shellfish

• Broodstock and Spat– Cell Size 10-24 microns– Species

• Tetraselmis sp.– Green

• Thalassiosra sp.– Diatom

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

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

Micro Algae Culture

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

Culture Water

• Sources– Seawater– Saltwater wells– Prepared seawater

• Salinity– 26-32 ppt

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

Nutrient Enrichment• Guillard’s f/2

– Part A and B

– 0.5 ml/L each part

– Na2Si03 for diatoms

Nutrients Conc.(mg/l Seawater)

NaNONaNO33 7575

NaHNaH22POPO44.H.H22OO 55

NaNa22SiOSiO33.9H.9H22OO 3030

NaNa22CC1010HH1414OO88NN22.H.H22O (NaO (Na22EDTA)EDTA) 4.364.36

CoClCoCl22.6H.6H22OO 0.010.01

CuSOCuSO44.5H.5H22OO 0.010.01

FeClFeCl33.6H.6H22OO 3.153.15

MnClMnCl22.4H.4H22OO 0.180.18

NaNa22MoOMoO44.2H.2H22OO 0.0060.006

ZnSOZnSO44.7H.7H22OO 0.0220.022

Thiamin HClThiamin HCl 0.10.1

BiotinBiotin 0.00050.0005

BB1212 0.00050.0005

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

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 killedMotile cells should be killed

Harvest and Feeding

• 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

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

Harvesting and Feeding

• BatchBatch– Total harvest occurs once or over several

days

• Semi-ContinuousSemi-Continuous– Works well with diatoms– Part of the algae remains in the vessel– New media is added to replenish the algae

removed

Marine Fish Larval Culture

• Relies on zooplankton

Marine Rotifer Brachionus plicatilis

• Culture units– 40L plastic bags– 40L cone-bottomed

tanks

• Temperature 27-30 C• Salinity 26 ppt

Rotifers

• Laboratory production– 100 to 200+ m size– 2-3 week life span– small size suitable as

first food

Feeding Marine Fish

• Rotifers– Typical first food in

hatchery– Feed algae or yeast – Enrichment needed

Artemia

• Feeding of older larvae

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.

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)

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*

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.

Use of copepods...

•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.