Different Shrimp Disease and cure technique Part 01

Introduction

Diseases constitute one of the most important problems and challenges confronting shrimp farmers today. In present situation in Bangladesh, most of the shrimp farmers face several shrimp disease problem. White Sport Syndrome Virus (WSSV) is the one of the main disease for the shrimp farming in Bangladesh. But there is a wrong idea among the farmer regarding virus (WSSV) disease. Many farmers if their farm shrimp died they think this is due to virus. But virus is not only the one of the cause of shrimp died. Shrimp, like all animals, are subject to a variety of diseases. But accept WSSB, those disease are easily curable. Here I will discuss (Part 01-02) different shrimp disease and how to cure those disease.

                                                                   PART: 01

Gas problem or Bottom Purification: 

Up to one third of the content of feed used in culture system may be indigestible. And 25% of the feed become wasted. That’s why massive gas problem occur at the middle of the culture stage. If we do not solve it fish faced huge suffocation problem and mortality occur. We can easily understand by following diagram.

Feed waste in different way

Over all Treatment: 

When ammonia rise in pond, fish can not extract energy from feed effectively.Ultimately fish going to comma and result in death.Specially unionized ammonia is very toxic and predominates when pH high.

Treatment:

Ø  CaCO₃ (25kg/Acre) + Sand. After 1 day then 1 Super PS dose. Because its oxidize pond bottom.

      Ø  Zeolite 70 kg/Acre.

      Symptoms to detect NH3 affected pond:

      The only way you can detect ammonia is to use a proper test kit. So check your water weekly for ammonia, nitrite, nitrate and pH, and check again if your fish look unwell or are acting unusually.       

      Source of ammonia gas: 

Ø  Fish excreta

Ø  Poor Decomposition of organic matter produce ammonia

Ø  Nitrification

Ø  Plankton crash.

Ø Feed wastage

Ø   

     The signs of ammonia stress on fish:

        Ø Lethargy

        Ø Loss of appetite

        Ø Hovering at the bottom of the tank (especially for surface dwelling fish)

        Ø  Gasping at the surface

        Ø Inflamed gills

        Ø Red streaks or inflammation in the gills

        Ø  Inflamed eyes or anus

  

        Easy technique to control ammonia:

Ø  Regulate feeding rate.

Ø  Water exchange

Ø  Add organic fertilizer.

NH₃ reduction technique:

      Ø   Supper PS (Photosynthetic sulfur bacteria) -------- Early stage 2 L/Acre and middle stage 4 L/Acre. Because Super PS oxidized pond bottom.

      Ø  Sodium Chloride 100 kg/ Acre.

      Ø  Chain dragging.

      Culture phytoplankton because algal uptake huge amount of ammonia.

      Symptoms to detect H2S affected pond:

      The  most common way to detect H2S is by a rotten egg odor that may bubble out of the water when bottom sediment is stirred-up while seining fish, planting, or conducting general maintenance.

 
     Why H₂S is too much lethal for pond ecology:

1 create acid decomposition on water and soil, deplete oxygen.

2. Create high sludge on pond bottom and also create anaerobic condition which destroy beneficiary bacteria.
Ø  The moat destructive problem by H2S is gill damage 
Ø  opercular movement and respiratory arrest. 
Ø   poor feeding and an increased susceptibility to common diseases and parasites.

Accepted hydrogen level in pond ecology is  .002pm

H₂S reduction technique:

      Ø  Supper PS (Photosynthetic sulfur bacteria) -------- Early stage 2 L/Acre and middle stage 4 L/Acre.

NO₂  reduction technique: 

      Ø  Supper PS (Photosynthetic sulfur bacteria) -------- Early stage 2 L/Acre and middle stage 4 L/Acre.

      Ø  Sodium Chloride 1200-1800 kg/ha.

Death due to gas problem

                                                  

Loose shell problem:

Symptom of LLS:

Ø  Gap between the muscle tissue and exoskeleton (muscular dystrophy).

        

            Figure: Space between muscle tissue and exoskeleton

Ø  The shrimp does not moult for a long time.

Ø  Spongy Abdomen.

Reason of LLS:

Ø  One of the first indicators of the disease is an abrupt decline in feed consumption

Ø  Bloom crash, water quality and weather changes,

Ø   The aged ponds with high density during summer are prone to lose shell infection.

Ø  Nutritional deficiency.

Ø  Low saline.

Treatment:

Ø  Soda- mix-----------------------------------------------------------10 kg /Acre

Ø  Calmag--------------------------------------------------------------- 5-6 kg/Acre

Ø  Sodium Chloride.

Shrimp Disease part 02