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April 15, 2016


A Short Exchange from The Shrimp List


Giovanni Chasin   (Email Here in Brazil, some shrimp farmers are doing very well, getting 20-45 metric tons per hectare per crop of 18-gram shrimp in 90 to 100 days with greater than 90% survival—even in the presence of IMNV and other bugs and in one of the worst regions to grow Penaeus vannamei.  These great results are based on biosecurity, good management and system design.


In my opinion, IMNV resistance is still in the distant future, at least here in Brazil, and I don’t think biosecurity protocols against it will work on farms with large ponds.  Based on my experience, If IMNV hits countries like Ecuador or others on the Pacific coast of the Americas, it will not be easy to deal with it, even when working with specific pathogen free lines.


David Griffith (Email, a shrimp farm consultant and manager, currently on leave in Northern Ireland, responds:


Firstly, those are impressive results for production, with or without pathogens!  I would be interested in hearing what practices you think are key to meeting that level of productivity.  We have heard recently on this list that the best way to “prepare” animals is to expose them as early as possible to the natural environment.  Is that what is happening in Brazil?  Or is the tendency for high biosecurity and smaller, more manageable systems?


Regarding the IMNV and the risk it represents to Pacific coast operations in the Americas, I tend to agree with you.  Of course, it is probable that the IMNV virus has been present on the Pacific Coast of the Americas for some time, and there may be barriers to it becoming established and/or spreading that we simply are not aware of, so the question may be moot.  Lets hope that is the case!


Giovanni Chasin  (Email, responds: I have complete access to some of the facilities in Brazil that are producing those great production statistics, but, unfortunately, not to the highest producer doing super-intensive work.


Here are the specifications on the farms that are producing 20 tons per hectare per crop:


• Non specific pathogen free and non specific pathogen resistant postlarvae

• Common 1.8 mm, 35% protein extruded feed

• 30 horsepower per hectare of paddlewheel aeration

• Ponds with 20 parts per thousand salinity

• Alkalinity greater than 80 milligrams per liter

• Bioflocs

• Low water exchange

• Sludge removal

• Pond sizes from 0.4-0.6 hectare, 2 meters deep, totally or partially lined, with or
without greenhouses.

• Use of common or specific fertilizers, along with wheat bran and molasses.


Their neighbors that are not following these protocols are producing less than 0.7 metric tons per hectare per crop of 12 to 15-gram shrimp, or if disease strikes, they harvest 5-gram shrimp before they die.  Fortunately, there’s a nice market for 5-gram shrimp in Brazil.


Conventional farmers that are not experiencing big problems, those in the state of Ceara, for example, don’t plan to to migrate to intensive systems, mainly because of the high cost of setting them up.


I cannot imagine how exposing animals as early as possible to the natural environment is helpful.


Source: The Shrimp List (a mailing list for shrimp farmers).  Subject: Viral Transport in Ballast Water.  April 9 and 14, 2016.

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