Part II: Certifying & auditing aquaculture farms in Asia
Thursday,22 July,2010 10:17:08
Examining the risk of disease and screening infected populations
While certifying and auditing aquaculture in Southeast Asia, I also noted a degree of seriousness and dedication to ensuring that the processes involved in producing these animals, starting in the hatcheries and moving all the way through the processing plant, are consistent with state of the art and geared towards sustainability. This is an integral part of the business models of many companies. While there will always be ongoing issues with disease as far too many of the companies that are producing white shrimp do not seem to appreciate that Penaeus vannamei easily get ill and that SPF animals are not super shrimp, concerted efforts are being made to reduce risks where they can be.
Despite this optimism, there are signs that the specter of widespread uncontrollable disease is rearing its ugly head with well known characterized diseases affecting production in Indonesia (IMNV) and lesser known new and not yet characterized diseases affecting Vietnam and some areas in southern China. Disease outbreaks have been responsible for global shifts in the underlying economics of farmed shrimp in the past, and in my opinion, this will continue to happen. There are some who believe that we are not going to see this occurring in a manner that it has in the past, i.e. large country wide epizootics spreading rapidly into nearby countries. To some extent, this may be true in that the easy unregulated movement of broodstock and PLs between countries is for the most part history.
Unfortunately, this is not the case with all species and there are innumerable instances of infected broodstock being moved between countries with documents that show that they are free of certain pathogens based on PCR population sampling and limited surveillance. Given the seriousness of moving diseases in this manner, population screening is not suitable. Individual animals need to be tested and for diseases that are known to be problematic, not just diseases of convenience.
Recently, I consulted for a project that was moving adult P. monodon broodstock into an area where they had never been cultured before. These animals were screened on a population basis and held in quarantine after arrival in country. At my insistence, each animal was tested for a variety of potential pathogens and sure enough, a small number of them turned out to be carrying viruses that would have wiped the project out within the first 90 days of stocking. This was missed due to the lack of understanding of the correct use of the tools that are used for screening populations.
Traditional approaches towards disease control rely on screening generally by the use of PCR, biosecurity, history and quarantine of stocks prior to being used. For many diseases these approaches have to be modified. Screening using traditional population sampling procedures does not eliminate risks even if everything else is taken into consideration. Low levels of pathogens can lie dormant in animals and it is only after they are stressed significantly that these pathogens express themselves and their presence suddenly becomes detectable.
Many purveyors of broodstock and juvenile fish and shrimp in Southeast Asia go through the motions of testing without being genuinely concerned with ensuring as high of a degree of probability as is economically feasible that they are not selling their clients animals that carry serious potential pathogens and that in turn infect others. Until customers understand this, demand better testing, are willing to pay for it and insist that they are protected, disease will continue to be spread when it can be controlled.
This is not to say that diseases can be absolutely prevented. Taking the right steps though and understanding what biosecurity measures need to be taken to lessen chances of disastrous disease outbreaks is critical however towards minimizing the impact. Some areas of the world are better are at understanding this and better at reducing the risks. Others are simply not there yet.
For those of you in the business of selling aquaculture-produced fish and shrimp, you need to bear this in mind as disease outbreaks can and will continue to dramatically impact the supply, causing price fluctuations and in extremes, an inability to meet demand. Most of these risks can be addressed as they are not inherent components of the system itself but instead are a result of a failure to pay attention to some of the critical details of the process. Make sure that your suppliers understand that sustainable practices must also focus on disease control and prevention. Too many companies that claim to be sustainable ignore this at their own risk.
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Part 1: Certifying & auditing fish farming in Asia
Wednesday,21 July,2010 08:33:19
Paradigm shifts may reduce costs of production but do they reduce the risks of disease as well?
So far this year I have spent more than two months in SE Asia, auditing farms, hatcheries and processing plants for compliance with the Best Aquaculture Practice (BAP) standards developed by the Global Aquaculture Alliance (GAA) and vetted through the Aquaculture Certification Council (ACC). Starting at the beginning of 2010, the processing plant and farm audits are being handled through two widely recognized certification bodies, Global Trust of Ireland and NSF Surefish of the USA.
I have traveled to Southeast Asia many dozens of times over the last few decades and during these many trips and more so recently I have noted some ongoing trends which are having and will likely continue to have global consequences.
Perhaps one of the most startling trends that I have noted is the incredible levels of productivity that seem to be prevalent on shrimp farms in China and throughout many parts of Southeast Asia. Through innovative adaptation of what a decade ago was considered to be a challenging production model, farmers now routinely achieve extremely high yields. Many farmers have taken the core elements of high density shrimp farming developed in Belize by Belize Aquaculture Limited (BAL), and improved upon them.
• Using plastic lined relatively small, shallow ponds (BAL model is deeper ponds and slight larger).
• Stocking at very high densities (150 animals per square meter or higher) relative to the traditional norms in much of Central and South America for the last three decades.
• Closing the ponds during the production cycle. Using water to fill the ponds and a little make up water to adjust water levels as water evaporates. Water can be reused (as BAL was designed for) although in many cases it is discharged into the ocean. Sediments are retained for disposal elsewhere.
• Aerating at and immediately below the surface using paddlewheels and from the bottom ensuring that DO levels never drop below levels that most shrimp farmers in the Americas claim are not problematic to growth. Keeping DO levels close to saturation is essential for optimal growth.
• Stocking with Specific Pathogen Free (SPF) shrimp. It is ironic that these were developed by the expenditure of US tax dollars with the motive of assisting US shrimp farmers. In turn it has resulted in a few US companies making large amounts of money and is the basis of a very successful SE Asian white shrimp farming industry.
These technologies have resulted in farms with phenomenally small environmental footprints producing 25 or more MTs of shrimp per cycle per ha. A 1000 ha farm in Southeast Asia could produce 50000 MT per year compared with the Americas, where a 1000 ha farm might produce 4000 MT of shrimp. While this approach is risky from a disease standpoint, in the absence of problems in many areas of Asia, it has paid off beyond many farmers wildest expectations.
It is ironic that systems that originated in the Americas combined with genetically improved animals that originated in the Americas are making many farmers rich in Southeast Asia, while farmers in the Americas are often struggling or going out of business. Production of farmed shrimp in Ecuador for 2009 was estimated to be 140,000 MT from around 120,000 ha. In SE Asia this 120,000 ha would be producing more than 6 million MT, double the current total global production (assumes 25 MT/ha with two crops). The 140,000 MT produced could be produced from less than 3000 ha!
Costs of production in Souteast Asia are typically very low. Labor costs factor into this although feed and seed costs do not. It appears that the more shrimp you produce in a smaller volume of water the lower your overall cost of production become.
Many predict that China’s burgeoning middle class will in the not too distant future consume all that they produce domestically and that they will be importing product from elsewhere as well.
Indeed, it is apparent that China cannot produce what it needs for itself. Domestic consumption is increasing at a rapid rate and the prices commanded locally are better than the price that is typically paid when the product is exported (although this is to middle men-the consumers pay higher prices in the U.S. than they do in China). This has the potential for driving up prices everywhere for farmed shrimp and the downside of lowering demand in the traditional strong markets, the USA, the EU and Japan. Indeed this appears to be happening and not just with farmed shrimp, but with farmed Tilapia as well.
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