Transcript Lorem Ipsum - University of Georgia College of

Freshwater Prawns in Georgia
Gary J. Burtle
Animal & Dairy Science
The University of Georgia
Freshwater Prawns
• Machrobrachium
rosenbergii
• An exotic shrimp from
Malaysia
• Tropical
• Lives in freshwater for
part of its life-cycle
U. S. Prawn Culture
• Of interest for over 25 years.
• Limited by the availability of seed stock.
• Cultured in Texas, Kentucky, Mississippi,
South Carolina, recently in Georgia.
• Average production 500 to 800 pounds per
acre.
• Maximum production about 2,500 lb/A with
structure and higher stocking densities.
Reasons for Caution when
Considering Prawn Production
• More difficult to raise than catfish
• High prices are a temporary effect of a
niche market
• Product quality is unique to freshwater
prawns
• Tail is only 40% of total weight
• Juveniles are very expensive
Prawn Production in Ponds
•
•
•
•
•
•
•
Prepare pond for stocking (early April in Georgia)
Stock 10,000 to 30,000 juveniles per acre
Fertilize for first 30 days
Feed a sinking feed during months 2-4
Monitor and control oxygen and pH
Use narrow ponds less than 2 acres in size
Harvest before water falls below 60 degrees
Preparing Ponds for Stocking
Prawns
•
•
•
•
Drain, dry, disinfect
Fill quickly within 14 days of stocking
Fill with filtered pond water if possible
When using well water, be certain of zooplankton
abundance before stocking
• Stock grass carp for weed control (20 or more per
acre)
• Install structure (horizontal is better than vertical
placement)
Prawn Pond with Structure
Proper Sized Juvenile Prawns
• 60 day old, 95/oz
• 28-35 day old, 250 to
280 per oz
• Uniform size very
important
• Careful handling and
stocking are essential
to juvenile survival
• Avoid overcrowding
Feeding Prawns
•
•
•
•
Start with cottonseed meal and N-P-K
Use sinking catfish feed for 500 to 800 lb/A
Use shrimp diet for possibly higher yields
Monitor zooplankton with net during first
month
• Feed over entire pond area
• Estimate feed rate based on prawn samples
Water Quality in Prawn Ponds
•
•
•
•
•
Aerate continuously.
Keep oxygen above 3.0 ppm.
Monitor pH twice each day.
Flush with water to keep below 9.0.
Possibly add gypsum to lower pH (1,000 to
2,000 pounds per acre added as needed).
• Keep water deeper than 3 ft to prevent
wading bird predation.
Prawn Harvesting
Harvest Procedure
• Seine most of prawns with water at 1/2
depth
• Use 1/2 inch mesh seine, grade with bar
grader (63/64 inch spacing)
• Consider partial harvest one month before
end of season
• Final harvest requires pond draining
Prawn Marketing
• Entirely up the the individual producer
• Local sales of fresh prawn limits the volume
of the market in Georgia
• Rural locations will usually get lower prices
than urban areas
• Entire harvest must be sold within a few
days
• Removing heads constitutes processing
Economic Sketch
• Breakeven at 1,000 lb/A is about $5.00 per
pound
• Juveniles cost $1,500 to $3,000 per acre
• Feed costs $300 to $550 per acre
• Aeration costs $200 to $400 per acre
• Labor cost $800 to $1,200 per acre
• Variable cost total$2,800 to $5,100 per acre