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China/Thailand

Big Problems at the Start of 2017

 

The following exchange took place on The Shrimp List, a free, email-based, mailing list for shrimp farmers that distributes information posted by one member of the list to all the other members of the list.

 

Freddrick Poh (fredpohkh@yahoo.com): In China, shrimp prices are going to go up a lot this year.  Nearly all the postlarvae stocked in late February 2017 were wiped out by day-30 of growout!

 

Daniel Gruenberg (daniel@acquestra.com): Freddrick, I also see something similar in Thailand right now—massive mortalities, emergency harvesters, markets overwhelmed with shrimp and dropping prices.  My sources both in the southern and eastern regions of Thailand report large mortalities!

 

I’m not quite sure what is going on, but we have learned a lot about EHP, a microsporidian parasite that infects shrimp.  You cannot trust most labs that do polymerase chain reaction (PCR) testing for EHP.  We took the same samples to three different labs, one government and two private.  They all reported negative results, but when we added a step to the DNA extraction step, negatives became positives!

 

So far, the Fish Vet Group’s test (a differential staining protocol) seems to be the most reliable diagnostic tool for EHP.  STANDARD DNA METHODS DO NOT WORK WITH EHP!  Government certified EHP-free larvae might not be EHP-free.

 

Now that we are armed with a new DNA-based test that is reliable we will be looking deeply into the possible vectors and contamination routes for EHP in the hatchery.

 

Source: The Shrimp List (a mailing list for shrimp farmers).  Subject: Integrated Multitrophic Systems.  April 27 to May 3, 2017.