12/01/2025
Running Mortality Syndrome (RMS)
Early Mortality Syndrome (EMS) or Hepatopancreatic Acute Necrosis Syndrome is a fairly new disease that affects shrimp.
Symptoms:
-The onset of RMS found to occur between 35 and 45 days of culture (DOC),where a small population suffered mortality and the farmers can collect these dead shrimps by netting.
-In the early stages of disease shrimp start showing gross signs,such as the
antennae cut and Uropods turned normal to
red in color.
-Later on Hepatopancreas turns
reddish yellow and finally entire
body turns dark red in color.
-Affected shrimp develop white patches between 3rd and 4th abdominal segment.
-Continuous internal mortality may notice
throughout the day.
-The dead shrimps are settled at the bottom of the tank and will not come to sides or surface.Farmers will come to know about this only when dead and cannibalized shrimp come to check tray.
-The occurrence of mortality is directly
proportional to stocking density. Higher the stocking density early the mortality sets in.
-Mortality rate is relatively more in low saline ponds.
-White or yellow f***l matter is noticed
in the gut.
-Mortality noticed only during inter-moult stage.
-Very poor survival and high feed conversion ratio.
-Mortality become severe at around 90DOC and farmers forced to harvest their crop prematurely.On an average, about 40% of the stocked shrimp survive and grow to a harvestable size.RMS often caused pond biomass to fall substantially in farms with mortality rate reaching 70%.
Management/Controlling:
-Regularly remove the dead
shrimp from the pond.
-Reduce the stocking
density by partial harvesting reduced the
mortality.
-Reduced feed reach the production up to 30 count without RMS).
• The culture practices like stocking bigger post larvae,reducing stocking density, nursery management, partial harvest ,strict feed management and Polyculture will
reduce the incidence of RMS.
Source paul
