EFFECTS OF WATER TEMPERATURE ON FILTRATION RATE OF MICRO-ALGAE ISOCHRYSIS AFFINES GALBANA BY BLACK LIP PEARL OYSTER SPAT (PINCTADA MARGARITIFERA)

This study was conducted to compare the effects of varying water temperatures on filtration rate of micro-algae Isochrysis affines galbana by Pinctada margaritfera spat on microalgae. To determine the optimum temperature and maximum filtration rate, 10 pearl oyster Pinctada margaritfera spats with mean total and total hinge length 32.67±2.76 and 31.57±2.90 respectively were stocked in 70 liter rectangular glass tanks supplied with filtered seawater. The spats were exposed to seven treatments of temperature including 18.5±0.21oC, 20.5±0.21oC, 23±0.1 oC, 24.5±O.31oC, 26.5±0.21 oC, 27.5±0.15oC and 28.5±0.21 oC with 3 replicates.
The results of filtration on Isochiysis affines galbana showed that the maximum filtration of spats on microalgae cells and water volume were 181,324,595 cells and 3626ml per hour and 635,031,212 cells and 12700ml per two hours in 27.5±0.15oC, respectively. The minimum filtration of microalgae cells and water volume were 5,224,028 and 104ml per hour and 65,874,413 cells and 13l7ml per two hours in 18.50±021oC, respectively. The results of this study demonstrated that the optimum tem perature for maximum feeding of spats on Isochrysis affines galbana is 27.5±0.15oC.