Research conducted on early mortality syndrome (EMS) at a large integrated shrimp farm in Malaysia has indicated that the disease repeatedly manifests in ponds with an increase in pH to 8.5 to 8.8.
Conducted by Noriaki Akazawa, managing director of Agrobest Sdn. Bhd., with assistance from Kinki University and the National Research Institute of Aquaculture in Japan, the full research results are being prepared for publication in a peer-reviewed journal.
EMS, more technically known as Acute Hepatopancreatic Necrosis Syndrome (AHPNS), has had a significant impact on shrimp production in Southeast Asia. The research results are encouraging because they provide shrimp farmers with a tool to improve management of the disease in ponds.
A review of water quality data from approximately 80 affected and unaffected ponds stocked during the same month indicated several water quality differences that were correlated with outbreaks. The researchers then conducted replicated aquarium trials with controlled levels of various parameters.
These tests confirmed that the disease repeatedly regressed at lower pH (around 7) and manifested at higher pH (8.5 to 8.8). Survival rates in Agrobest ponds have greatly improved with management of pH to avoid the zone of EMS susceptibility.
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