Effect of Water Quality Parameters on Growth and Survivability of Mud Crab (Scylla tranqubarica) in Growout Culture at Kakinada Coast Andhra Pradesh

Abstract

An experiment was carried out to study the effect of water quality parameters such as salinity, temperature, pH and DO, ammonia, nitrate and nitrite on growth and survivability of mud crab (Scylla tranqubarica) in growout culture in brackish water fish farm at Fisheries Research Station, Kakinada. The growth and survivability mainly depends on water quality parameters and rate of feeding. In contemporary days the water quality parameters effect is more in the field level due to the rapid climate change in the coastal regions. The experiment has been started with pond preparation; it includes drying, ploughing, water culturing with good pre & pro-biotic. Natural seed was purchased and stocked @ 200 no/0.5 acre pond and fortnight sampling has taken to see the survival and growth associated with the water quality parameters. The study notify that among the water quality parameters salinity plays very important role as it decreases to the 10.5 ppt while the survival rate has been dropped from 87 to 45 percentage. At the same time ADGR g day^-1 has been drops from 2.68g to 0.97g when salinity decreased. In addition to that DO also affect survivability and growth, due to the slight changes in temperature. But the rate of survivability has been constant when salinity has maintained at range of 15-25 ppt. So among the water quality parameters the salinity was limiting factor for determining the survivability and growth of the crablets in the growout culture. Perhaps drastic fluctuations in temperature and salinity mainly due to the irrational rain falls, very high temperatures and sever humid conditions causes the mass mortality in the farming sector.