Research & Development and Product Certification

Progress at Aquafarm 4

Research and Traceability Agenda Moves Forward

SIAF Chief Scientific Officer, Dr. Tony Ostrowski has been given charge to advance some of his planned innovative research and product traceability agenda at AF4 in Zhongshan, a.k.a. the MegaFarm.

Three objectives have been targeted:

  1. Research ways to improve giant prawn (Macrobrachium rosenbergii) culture in AF4 APRAS tanks.

  2. Initiate a disease surveillance and prevention program for the entire farm.

  3. Initiate a pilot traceability program as a model for Tri-way group farms.

Research to Improve Density and Production

The production of giant prawns is a key driver of the economic model and pro forma projections for Tri-way. While the technology was confirmed in smaller tanks at AF1 & AF2, improvements in that technology will help improve projections and cost validation for the MegaFarm. The R&D team will conduct a series of trials in the 50, 150, and 1,200 cubic meter (working volume) APRAS tanks targeting improved water turnover, cleaning, and refuge design to increase density, survival, and overall production.

The culture of giant prawns is normally problematic because of a phenomenon in this species called Individual Heterogenous Growth, or IHG. There is naturally occurring very different growth and development patterns in this species between males and females, and especially between males. IHG manifests during the early nursery stages and affects subsequent growth and survival of a cohort.  Females are generally smaller, but males also develop a behavioral hierarchy based on available surface area of the culture system. So-called, “Blue claw” males grow quickly and prevent the development of other males, referred to as “Orange claws.” “Orange Claw” males are those essentially waiting to have more space available so one of them can grow quickly and become a “Blue Claw.” The problem is “Orange Claws” won’t grow if they don’t have this, or if “Blue Claw” males are present in too high abundance. Aggressive and cannibalistic behavior is increased as well.

IHG is the reason why most pond culture of giant prawns is done at very low density, with stocking densities of 1-20 animals/square meter vs. 100 or more animals stocked per square meter as with the ubiquitous Pacific White shrimp (L. vannamei). Typical harvest densities for giant prawn are only 0.5-5.0 metric ton/hectare compared to up to 30-40 metric ton/hectare for Pacific white shrimp, achieved in recent years.

The SIAF phased-growout, partial harvest strategy combined with APRAS circumvents some of these issues and allows SIAF to produce giant prawns at much higher densities and with much better production than typical pond culture of the species.

Research at AF4 will help verify the technology in the overall larger APM tanks (compared to AF1 & AF2) and begin to address increased surface area to provide more space within tanks. Research will also address alternative harvest strategies, and improvements in water turnover and self-cleaning aspects of the APMs.

This video from AF2 shows how SIAF’s creation of “refuges” provides more hiding places and surface area to help increase stocking density in APM tanks, and reduce IHG.

Prawns using Refuges.07.2017 from Sino Agro Food, Inc. on Vimeo.

Disease Surveillance and Prevention Program

Disease is the number one concern in aquaculture. It is not only important to monitor stocks to determine disease status of a farm and react quickly, but also to find ways to prevent disease from occurring in the first place. Diagram 1 indicates the premise for any animal to contract a disease. You must first have the host, or the animal you are raising, then the pathogen, or the organism that has the potential to cause a disease, and finally some sort of stressor that lowers the resistance of the animal which then causes it to contract the disease carried by the pathogen. 

Diagram 1. There are three factors needed to contract a disease: a host, a pathogen (a disease-causing agent), and some stressor that allows a pathogen to become virulent (i.e., the ability to infect the host and cause a disease). Good biosecurity practices prevent excludable pathogens from entering the system. Non-excludable pathogens arise within the system and cannot be prevented from entering the system “a priori.”

AF4 has implemented a biosecurity program that helps with preventing the introduction of “excludable” pathogens. These are pathogens that can be physically excluded from getting into the culture tanks, like viruses that are carried by small crustaceans that enter via the source water. Bio-secure measures to prevent that kind of introduction consist of screening the incoming water to prevent most from entering, and then disinfecting the water (with chlorine, or Ultra-violet light) to kill anything else.

Non-excludable pathogens are those that arise de novo within the tanks due to some environmental or other pressure being put on the cultured animals. This would include mostly certain bacteria species, most notably Vibrio, sp., common to RAS and other intensive-type of rearing systems.

An aquatic disease-specialist will be hired to initiate the disease surveillance program. A microbiologist will also be hired to help with that monitoring and to concentrate research efforts on non-excludable pathogens. The primary directive is to help prevent disease, rather than treat the disease after it occurs.

To that end, Quorum Sensing/Quorum Quenching research efforts will be conducted at AF4 in APRAS tanks and in the laboratory. In the most simplistic terms, both “good” bacteria (those that promote a healthy environment in which animals can live) and “bad” bacteria (those that if encouraged to grow due to unhealthy conditions, will cause disease) arise and exist in tanks and water naturally. This occurs even after water and tanks have been totally disinfected.

In fact, there is always ongoing competition between “good” and “bad” bacteria for dominance in the system. Bacteria are known to “communicate” with each other to help promote the growth and dominance of their own or like kind. This is called Quorum Sensing, referring to the finding that it is normally a consortia of bacteria which communicate such that a “quorum” is reached, and a protective and nurturing biofilm for either “good” or “bad” bacteria is created.

Quorum Quenching refers to research that certain manufactured (or natural) proteins can disrupt that “communication” and prevent a “quorum” from being reached. Depending upon the “good” and “bad” bacteria identified in the system and their numbers and interaction between different consortia, methods can be devised to promote growth and dominance of “good” bacteria, and prevent the growth and dominance of the “bad” bacteria.

Diagram 2. represents “communication” among bacteria, called Quorum Sensing. Quorum Quenching can help prevent this from occurring and prevent the growth and development of unwanted bacteria in the system if targeted appropriately.

In this way, discovered methods can be used to greatly reduce the chance of non-excludable pathogens causing disease and therefore reduce mortality in production at AF4, and eliminate any need for use of antibiotics.

Pilot Traceability Program

Key to achieving documented reputation of sustainable production as a goal of Tri-way Group farms is to have the group achieve third-party, internationally- recognized process certification. Examples include the Best Aquaculture Practices (BAP), obtained through the Global Aquaculture Alliance, or the Aquaculture Stewardship Council (ASC), obtained through the World Wildlife Fund.  Process certification verifies that the practices that occur on the farm are biologically, environmentally, and socially responsible. Process certification is different than HACCP (Hazard Analysis Critical Control Point) certification used in processing plants to ensure processing of raw material is being done safely under good health standards, although HACCP principles of critical control points are used in creation of process certification standards.

In fact, obtaining third party process certification is a requirement of a recent institutional loan facility obtained for Tri-way, to promote export marketing and sales of Tri-way farm products. Third party process certification is becoming increasingly required by many of the larger importing wholesale and retail outlets. Local or country certifications are not accepted. Currently, less than 5% of all aquaculture production in China is process certified, using internationally accepted standards.

As a first step in orienting Tri-way Group farms towards process certification, a pilot project will be initiated at AF4 to implement a product traceability exercise, as one of the requirements for certification. This will also allow AF4 to collect needed biological performance information (growth, survival, feeding rates, etc.) and to enumerate biological assets, also needed for balance sheet recognition. This pilot project will then be expanded to other Tri-way Group farms, with eventual electronic linking that will lead to application for official certification through the chosen certification body.


To achieve these objectives, plans at AF4 are now being made to improve the quality of source water, construct a temporary microbiology and pathology lab, and hiring of specialized staff.  All is targeted to be in place by the end of the summer. Plans are also being made to build the boiler system needed to run APRAS tanks during the winter. This represents an important step towards advancing the science and agenda of sustainable aquaculture production for SIAF/Tri-way.

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