Abalone Cage Culture, Rearing Operation Part 3

Rearing Operation

Transporting Abalone Juveniles

Transport of abalone juveniles should be done early in the morning or during cold weather conditions. Abalone juveniles are contained in PVC pipes enclosed on both ends with ‘A” net tied with rubber bonds.

Acclimation and Stocking

Before stocking it is best to ensure that ail nets were properly checked with damage, cleaned with debris and fouling organisms and possible presence of predators.

Stock mono sized abalone juveniles with 1.0 cm shell length in nursery cage at a stocking rate of 600 juveniles per cage. Stocking should be done early in the morning or during cool weather conditions.

Before releasing the juveniles, acclimation is done by placing them in basins where they are sprinkled with fresh seawater until completely submerged. When abalone juveniles are observed to creep inside the pipes check the temperature of the seawater. Remove the A net cover at both ends of the pipes and place inside the nursery cages.

Slowly submerged the nursery cage until the juveniles were observed to have adopted with the environment. Fasten firmly the cage into the raft After 6 hours check the cages for possible mortalities and immediately remove them from the cage as it can attract predators to enter the cage.

Feeds and Feeding

Fresh Gracilaria are being fed to abalones ad libiitum two to three times a week. Abalones are very voracious feeders. They consume large amount of seaweeds that is why the farm should be near to large volume and year round supply of seaweeds (Gracilaria). The minimum food conversion ratio (FCR) is 13 to 15 kilos, which means that it requires 13 to 15 kilos of seaweeds to produce a kilo of abalone. The table below shows the daily food consumption of abalone in relation to size.

Calculating weekly feed consumption of abalones.

  • Feeding/cage/week = n x ABW x FR X 7
  • Where n: no. of abalones per cage
  • ABW: average body weight
  • FR: feeding rate/day
  • 7: no. of days/week

Example: Amount of feed/cage/week

  • = 600pcs x 1g / pc x 35% / X7
  • = l,470 g or 1.4kgs/cage/wk

Stock Sampling

To determine the growth and feed requirements, stock sampling must be done every 15 days. Initial size and weight are being recorded to determine the growth rate of stock and to determine the daily food ration of the stock.

Water Quality and Stock Management

Daily water quality should be monitored. Such water parameters to be, monitored are the following:

  • a. Turbidity- water transparency should not be less than 2 meters secchi disc reading.
  • b. Salinity- water salinity in the culture area should be between 30 to 35 ppt.

Stock Management

Proper monitoring and stock management contributes to the success of abalone grow-out operations.

  • Stock and transfer every two to three months.
  • Harvest every two to three months after the first six to nine months of operation.
  • Periodic sampling for weight and length gains
  • Two to three times feeding per week.
  • Daily observation and checking of cage damage and cleaning of dogs from cage netting materials.
  • Round the dock watch.

Economics

Basic Assumptions:

  • Project duration – 3 to 4 years
  • Stocking Rate per cage:
    • a. Nursery cage – 600
    • b. Transition Cage – 300
    • c. Grow-out – 150
  • Stocking size (cm) – 1 cm
  • Cage area – 50cm dia. x 50cm dept
  • Stock per Crop:
    • a. 5-10-20 module – 3,000
    • b. 7-14-28 module – 4,200
  • Price of Abalone Juveniles – P5.00
  • Survival Rate – 90%
  • Feed Conversion Ratio (FCR) – 11.37 – 15.16
  • Price of Seaweeds (Php/Kg.) – P4.00
  • Production per crop per module:
    • a. 5-10-20 module scheme – 180-270 kg
    • b. 7-14-28 module scheme – 252-378 kg
  • Final size of harvest – 55-100 g
  • Culture Period (Months) – 6 to 9
  • Farm gate price of abalone (Php/kg) 450.00 – 600.00

 

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