2.5. Some common diseases and their treatments

2.5.7. Black gill disease

* Signs:
– Shrimp with this disease often has its gill color changed from ivory white to brown or black with lesions in gills.
– Shrimp has respiratory difficulties, floats or clings to the shore, eats less or skips meals and dies. There are also shrimp deaths in a large scale when the levels of oxygen fall below the threshold of adaptation.

* Pathogen:
– Because shrimp lives in water environment contaminated by sediment, organic matters or algae, these substances bind to shrimp gills and cause the disease.
– In the pond with high levels of NH3 and NO2, black gill disease can also occur.
– In addition, shrimp has black gill also because black melanin, a natural product of the immune system of shrimp and crab, appears in shrimp gills.
– The disease is common in whiteleg shrimp ponds from the 2nd month of farming.

* Preventions – Treatments:
The causes of black gill disease are from contaminated environment, too many organic substances at the bottom of the ponds, and high levels of toxic gas. Thus, use these solutions:
– Use bioproducts to clean the ponds and absorb toxic gases.
– Feed shrimp with vitamin C.
– Change water at the bottom if it is appropriate to the conditions.

Source: Temporary process for safe brackish-water shrimp farming in areas affected by diseases in Vietnam. According to The Official Dispatch No. 10/TCTS-NTTS. January 6th, 2015. Vietnamese Directorate of Fisheries

Viet Linh 2015. Translated by Sonia Linh V.