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BIOSECURITY PROGRAM MALAYSIA SHRIMP FARM

Great Lakes Bio Systems fully supports the guidelines set forth by the Good Aquaculture Practices (GAP) on biosecurity, and reprints here some salient content from their publication.

Implementation of good aquaculture practices (GAP) and biosecurity maintenance depend greatly on the system, the species, the recommended stocking season and the country/region where farming is conducted.

There are some common elements when dealing with GAP in shrimp pond farming along with many examples and references available on good management practices. Some of the most important are provided below:

 Pond and pond bottom preparation and water management prior to stocking:

  • Disinfect and dry pond for a period of two or more weeks (at least 4 weeks if pond has had a disease history prior to the next stocking);
  • Remove sludge and accumulated debris, and dispose away from the pond site;
  • Power wash biofilm formations and remove completely; spray BEL800 or LWT1000 + DFMs after this procedure;
  • Water filtration using twin bag filters of 500 microns and 200 microns mm mesh size;
  • Maintain water depth of at least 80 cm at shallowest part of pond;
  • Control of undesirable species (e.g., finfish, crustaceans, mollusks, amphibians, reptiles, birds, mammals) through physical means such as water filters or bird netting or tape, chemical and other means;
  • Chlorination and conditioning of incoming water at reservoir ponds and at culture ponds prior to use. Water conditioning to include proper disinfection, pH adjustment and monitoring, elimination of pyrites and heavy metals using DFM’s (Direct-fed Microbials) such as IRB800;
  • Liming, and mineral enrichments to maintain optimum balanced alkalinity level;    
  • Fertilization; and use of BEL800/LWT1000, DWTB800 to culture beneficial bacteria population, as well as IRB800 to accelerate and modulate plankton bloom;
  • Installation of proper and adequate pond aeration equipment based on a liberal calculation of horsepower vs planned stocking densities.

***Do not over-chlorinate as this may result in pathogenic over bloom

 Seed selection and stocking:

  • General health checks of PLs before stocking using traditional and molecular-based methods e.g., use of Nauplii and PL scoring techniques;
  • Use uniform size and dark-colored PLs, which must actively swim against the water current;       
  • Eliminate weak PL before stocking using formalin (100 ppm) stress for 15–20 minutes in continuously aerated water;
  • Establish a phased and On-farm Nursery Rearing Program of PLs for 15–30 days (each phase);
  • Stock PL’s into green culture water and avoid transparent water during stocking;
  • Stock PL’s using the recommended stocking season by the competent authority; and
  • Simultaneously stock PL seed in a single area to avoid the negative impact of juvenile and adult shrimp being affected by disease and transferring those to the newly stocked batches.

 Post-stocking management:

  • Use water reservoirs, and age 10–15 days before use on grow-out ponds; the use of shade netting to minimize lab-lab/macroalgae bloom during this aging process;
  • Regular usage of agricultural lime, especially after water exchange and rain;
  • No use of any harmful/banned chemicals/antibiotics;
  • Use feed check trays to ensure feeding based on shrimp demand, and discourage excess organic loading from uneaten feed;
  • Use properly-spaced and properly-calibrated auto-feeders OR broadcast feed across the pond using boat/floating device to avoid local waste accumulation;
  • Regularly remove lab-lab/benthic algae (manually or by water exchange), when present;
  • Monitor water quality to ensure appropriate pH, alkalinity and DO levels;
  • Conduct regular vibrio counts to ensure proper calibration of DFM applications into pond water and feed;
  • Daily inspection of shrimp in feed check trays to monitor health and dosing of feed enrichments such as DTM1000 mineral, LAA1000 enzyme-aminoacids, and HP800 probiotic;
  • Water exchanges only during critical periods or when adverse water parameters cannot be immediately corrected by double-dosing of DFM’s such as BEL800, DWTB800 and IRB800;
  • Run center drain siphon daily until clear; check pond bottom mud weekly for blackish organic waste accumulation and bad smell; and to correct the situation by siphoning and then using BEL800/LWT1000-infused zeolite aimed at center drain and pockets of accumulated wastes;
  • Monitor growth weekly using a cast net.

 Other:

  • Implement Biofloc Technology in pond culture
  • Adopt polyculture practices (Stock tilapia or milkfish) together in culture ponds

Health management:

  • Daily and regular shrimp behavior and health checks;
  • Correct diagnosis when a health problem occurs using lab analyses and PCR techniques;
  • If the stock is affected by general vibriosis, feed should be adjusted and or reduced; increase dosing of probiotics and enrichments (HP800, LAA1000, LPB800 and DTM1000); and water and pond bottom quality should be improved as necessary using water exchange and or use of DFM’s BEL800, DWTB800 and IRB800;
  • If a disease outbreak occurs due to an infectious disease, prevent the risk of spreading the disease to other ponds by eliminating stresses brought about by excess feeds, algae overblooms and or partial harvesting; or to prevent spread to other farms (e.g. no water discharge, no movement of infected stocks) and inform appropriate authorities;
  • Remove and safely dispose of sick or dead shrimp;
  • Emergency harvesting after proper decision-making;
  • No draining or abandoning of diseased/affected stocks from infected ponds; and
  • Destroy infected stocks as appropriate.

 Environmental measures:

Culture Ponds and Nursery:  Maintaining a good culture environment is one of the basic principles of disease control; it lessens stress that lowers the resistance of cultured animals to disease. The best way to maintain a good culture environment is to stock post-larvae in accordance with the production potential of the culture system; this will vary primarily with the amount of aeration applied and implementation of good aquaculture practices (GAPs). However, as GAPs may not always assure acceptable water quality, water quality monitoring should be conducted in ponds.

The most important variables to monitor are: dissolved oxygen, pH, salinity, ammonia nitrogen, and hydrogen sulfide. Wide daily fluctuations of pH suggest that phytoplankton blooms are excessive or that the water should be limed to increase its buffering capacity. The other variables usually will not be outside acceptable limits unless the amount of aeration is insufficient for the amount of feed input used.

Ensure adequate separation between Nursery Ponds and Culture ponds using physical structures and separate access, or by way of distance using separate facilities. Nursery facilities should be staffed separately, and built like a hot-house with walls made of plastic to control transfer of disease, and with shade cloth to better control plankton population.  Phased nursery programs can make use of high-stocking densities to be able to supply adequate PL’s to sustain a rolling and sustainable culturing and harvesting timeline based on farm production objectives.

Samples of Phased Culture:

A: Two-phase System: ...

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