White-Spot disease in Penaeus indicus from Choeibed farms

Objective: The site of Choeibdeh Abadan is located in Khozestan Province with 30000 ha area that Bahmanshir River is one of the greatest source of pouring water in to it. The raising activity of shrimp culture in this area started in the middle of June and continued up to the middle of November. This investigation have been carried out to elucidate how disease is distributed, what are the sources and causes of spreading the disease that occurs during raising the shrimps which can be useful to prevent the occurrence of the disease. Method & Materials: Important factors causing the distribution of white-spot are temperature variation that indirectly can affect pH, blowing local-wind with dust, seasonal immigration of sea birds in this site which can help the spread of infection. General non-biological factors such as salinity, temprature, pH, turbidity and weight were measured, consumed food was registered weekly and monthly. In time of appearing the signs of the disease in first pool, quickly all pools should be quarantined and entrance and exit of individuals to the site should be regulated. Results & Conclusion: The white –spot disease in summer 2004 was spread up in these farms and resulted in destroying 17 active farms. The center of contamination was in pool 13. After primary death in spite of a good quarantine condition, all shrimp destroyed in cl2, then farms were antisepticised by CaO. In contaminated farms, average of temperature was measured 26.6 0c , pH 8.4, salinity 13.67 ppt and mean weight of shrimp stock as was 3.12 gr. The elementary signs of white-spot are the redness of pliupods, red color on the tail area, soft carapace and easily separation. In this farm average salinity was below the tolerance range for shrimp (about 13-14 ppt ), so after 3 weeks white muscle observation early time. Result has shown that appearance and spread of white-spot in this area have an opposite relations with the salinity. Obviously, stress due to saltish had influence on decrease of growth rate, shrimps survival and weakness in front of white-spot, consequently shrimp stocks had shown great losses. Any stress condition in the contaminated area such as fluctuation of the biological factors, could intensify spreading of the disease.

کلیدواژه ها:

white-spot ، Choeibdeh ، P. indicus ، salinity ، contaminated