Investigacion De Sistemas De Cultivo Intensivo

An Update on Dr. Tzachi Samocha’s Research
 
 

 
Dr. Tzachi Samocha, a Regents Fellow and Professor at the Texas A&M AgriLife Research Mariculture Lab in Flour Bluff, Texas, USA, conducts research on super-intensive, zero-exchange, biofloc shrimp farming systems.  He hopes to develop a commercial system that could be located close to inland urban markets in the United States.  Inbiofloc systems, bacteria gobble up shrimp waste products and create a nutritious food chain that the shrimp feed on.  What could be more beautiful than that? In the fall of 2012, Samocha completed two new studies on his system.
 
 
Feed Study
 
The first study reports on the results obtained from six, 40-cubic-meter, zero-exchange, high-density (500 shrimp/m3) raceways in which two commercialfeeds were compared.  The results showed high yields, good growth and low feed conversion ratios (FCRs) for one of the feeds.  The following is a summary of the study that Samocha prepared for Zeigler Bros., a shrimp feed producer in Gardners, Pennsylvania, USA, one of the sponsors of Samocha’s research.
 

 
Use of limited discharge recirculating aquaculture systems can reduce diseaseintroduction and the potential negative environmental impact created by traditional pond culture where extensive water exchanges are being utilized.  In recent years studies at the AgriLife Research Mariculture Lab have focused on the use of a specially designed diet (HI-35) made by Zeigler Bros. and formulated for use in biofloc-dominated, super-intensive, zero-exchange systems.  These systems have highstocking densities (greater than 300 shrimp/m3) resulting in high biomass (greater than 3-6 kg/m3).  A 2009 study at the lab showed that high yields (9.29 kg/m3) and survival (88%) can be achieved with no water exchange and a density of 500 shrimp/m3 while using foam fractionators or settling tanks (STs) to regulate levels of particulate matter in the culture medium.
 
Objectives
 
1. Study theeffect of two commercial diets on shrimp performance and selected
water quality indicators under zero water exchange
2. Monitor shrimp growth, survival and FCR under zero water exchange
3. Produce market-size Litopenaeus vannamei at a high stocking density
with zero water exchange
4. Evaluate the benefit of using continuous dissolved oxygen-monitoring equipment
in operating a super-intensiveshrimp production system.
 
The study was conducted in six 40-m3 raceways.  Each 25.4 x 2.7 (68.5 m2) raceway was lined with EPDM (ethylene oropylene diene terpolymer, Firestone Specialty Products, Indianapolis, Indiana, USA), a liner previously determined to be non-toxic to shrimp.  Raceways were equipped with a center longitudinal partition positioned over a 5.1 centimeter PVC pipe withsprayer nozzles.  Each raceway had six banks of three 5.1 cm airlift pumps positioned equidistance on both sides of the partition.  In addition, each raceway had six 0.91 cm long air diffusers (1.9 cm OD, Aero-Tube™, Tekni-Plex Aeration, Austin, Texas, USA), a 2 HP centrifugal pump and a Venturi injector capable of introducing atmospheric air or a mixture of oxygen and air.  Raceways were filled with18 m3 of water used in a preceding 49-day nursery study and another 22 m3 of natural seawater and municipal freshwater.  Each raceway was equipped with a small commercial foam fractionator (VL65, Aquatic Eco-System, Apopka, Florida, USA) and a homemade settling tank (ST).  Shrimp used in this study were produced from a cross between Taura-resistant and fast-growth genetic lines developed by ShrimpImprovement Systems.  Two shipments of postlarvae (PLs) were delivered via overnight-air eight days apart.
 
Postlarvae received on April 12, 2012 (the 1st shipment) were cultured at low density (1,000 PL/m3) in the same 40 m3 raceways described earlier.  Postlarvae received on April 20, 2012 (the 2nd shipment) were stocked in two 20 m3 circular tanks at a higher density (3,000/m3).  Each...