The EMS scare

Shrimp farming is not an easy business for all. Despite this the trend for global production remains on an upward slope.

Recently there has been a lot of talk about EMS, or Early Mortality Syndrome, also known as AHPNS or Acute Hepatopancreatic Necrosis Syndrome. This syndrome is characterized by large losses of post-larval shrimp within the first 30 days of stocking. While there have always been issues post stocking the severity of this problem combined with its widespread geographical impact have generated some significant concerns.

A great deal of work has been done trying to determine what is causing this problem. The preponderance of evidence fails to support an infectious etiology and it appears that it may be related to some type of uncharacterized toxin. There is no evidence that it can be transmitted via broodstock and there is increasing evidence that simply modifying cultural practices can address whatever the underlying cause is. 

Parts of Thailand, the world’s largest exporter of farmed shrimp, have been affected in the last year and it appears that it may negatively impact production by as much as 30 percent. Given the widespread nature of the problem, China, Malaysia, Vietnam and most recently Thailand, it is likely that this will have the impact of tightening shrimp supplies, driving the price up. This will encourage development of shrimp farms in areas where they can take advantage of this, such as what is going on in Myanmar. The solution to the problem appears to be as simple as increasing biodiversity in the reservoirs and ponds by co-culturing the shrimp with herbivorous fish such as tilapia. Although not a wide spread practice some have reported that they have been able to minimize and even eliminate the problem in this manner.

We may never know the exact cause of the problem and there are areas where it is sure to linger. Adoption of co-cultivation with fish can be a relatively rapid process and once it is picked up regionally it could become the norm. Shrimp farming is typical of many farming practices in that it is usually monoculture and can generate organic wastes that are not always responsibly treated before being discharged. Of course there are those that would have you think that this is a very serious problem and it is for some farmers, but the reality is that organic pollution from non-treated human sewage and terrestrial agriculture operations dwarfs this discharge.  

So if I were selling and buying shrimp, I would enjoy the higher margins while they last. This problem will correct itself and it will not be long until we see even more shrimp in the market, hopefully at lower prices.


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SPECIALIST ON TUNA MARKET

Ms Van Ha

Email: vanha@vasep.com.vn

Tel: +84 24 37715055 (ext. 216)

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