Sanguinolaria rostrata is a deep site-burrowing bivalve commonly found in the southwest coastal waters of Taiwan. It has a long siphon extending to the surface. It is reported that exposed S. rostrata dies in few days without silt. However trussing it up rubber bands or cut off the hinge, it can survive for over one month in the laboratory. In this study the relation of shell closing and mortality for S. rostrata were examined and compared with the hard clam Meretrix lusoria in the similar environments. The size of adductor muscle and its ratio to the shell size, the strength of shell closing and the tissue structure of adductor muscle were examined. The quantities of fructose 2,6- biphosphate, an intermediate of glycolysis, in the adductor muscle of S. rostrata were determined. The results indicated that the average strength of closing shell for S. rostrata was 36.65% and for M. lusoria was 41.19%. The trends of tropic shell closing strength and the size of adductor muscle as well as shell closing strength and the adductor muscle wet weight were the same for the two species. The ranges of strength for muscle closing among S. rostrata of different sizes were smaller than those of M. lusoria. The average ratio of the adductor muscle microfiber to muscle was 55.6¢Mfor S. rostrata and 83.2¢M for M. lusoria. Therefore, the adductor muscle of S. rostrata is looser to M. lusoria. The concentration of fructose 2,6- biphosphate fluctuated widely to the unclamped S. rostrata in the first 6 hours and the concentration reached 7.58£gmole/mg at most. The concentration did not rise between 6 and 24 hours, indicating that unclamped S. rostrata consumed energy within the first 6 hours, then showed no sign of consuming energy.

Abstract The combinations of four temperatures (20, 25, 30, 35¢J) and six salinities (5, 10, 15, 20 ,25, 30psu ) were employed to study the effects of environmental factors on the speed of ciliary movement of the gill and the oxygen consumption of hard clam Meretrix lusoria and purple clam Sanguinolaria rostrata. The results show that, at the same salinities, the speed of ciliary movement of the gill and the oxygen consumption of M. lusoria increased with increasing temperature and reached the maximum at 30¢J, but declined at 35¢J. In contrast , the speed of ciliary movement of the gill and the oxygen consumption of S. rostrata increased with increasing temperature, and the maximum was at 35¢J. S. rostrata can adapt to higher temperature than M. lusoria does. At the same temperature, the speed of ciliary movement of the gill and the oxygen consumption of two bivalves increased with increasing salinity, reaching its maximum at 15~25psu, and declining at higher salinity ranges. These two bivalves like to live in estuaries. The maximal speed of ciliary movement of the gill and the maximal oxygen consumption of M. lusoria occurred at 30¢J, 20 psu (1.23 cm/min and 1.78 mgO2/hr/g, respectively). The ratio of the maximun to the minimun were 2.5 and 2.8, respectively. The maximal speed of ciliary movement of the gill and the maximal oxygen consumption of S. rostrata were at 35¢J, 25 psu (1.64 cm/min and 1.45 mgO2/hr/g, respectively). The ratio of the maximun to the minimun were 4.0 and 5.8, respectively. Temperature and salinity had more remarkable effects on S. rostrata than on M. lusoria. In another experiment, the combinations of four temperatures (20 ,25 ,30 ,35¢J) and three salinities (10, 20, 30 psu) were employed to study the effects on the speed of ciliary movement of the gill and the oxygen consumption of small M. lusoria and small S. rostrata. The results show that the effects of all temperature-salinity combination on the speed of ciliary movement of the gill and the oxygen consumption of the small bivalves were similar to that of the large ones. The physiological conditions of the small bivalves were similar to that of the large ones. The maximal speed of ciliary movement of the gill and the maximal oxygen consumption of small M. lusoria were at 30¢J, 20 psu (1.31 cm/min and 5.56 mgO2/hr/g, respectively). The ratio of the maximun to the minimun were 2.5 and 3.0, respectively. The maximal speed of ciliary movement of the gill and the maximal oxygen consumption of small S. rostrata were at 35¢J, 20 psu (1.67 cm/min and 3.96 mgO2/hr/g, respectively). The ratio of the maximun to the minimun were 2.9 and 7.1, respectively. Temperature and salinity had more remarkable effects on small S. rostrata than small M. lusoria. Our results also show that the oxygen consumption is positively correlated with the speed of ciliary movement of the gill in both bivalves (R2¡á0.94). The speed of ciliary movement of the gill can be regarded as an physiological indicator. The speed of ciliary movement of the gill of M. lusoria changed very significantly when the temperature was suddenly changed 5¢J or when the salinity was suddenly changed 10psu. The condition then stabilized only gradually. The speed of ciliary movement of the gill showed no pronounced variations after 50~70 minutes. We found that when the temperature or salinity was changed suddenly, the physiological condition of M. lusoria was disturbed and became stable after 70 minutes. M. lusoria died at 5psu (35¢J), but S. rostrata didn¡¦t. S. rostrata can adapt to higher temperature and lower salinity. The cultivation of S. rostrata is easier than M. lusoria. The effects of temperature changes were more significant than those of salinity. Temperature variations were more important than salinity variations on cultivation of M. lusoria and S. rostrata.

The environment of bivalve Sanguinolaria rostrata growth and reproduction is affected by temperature, salinity and algal concentration.The growth and fattening of the bivalves is closely associated with filter-feeding. Hence, the present work was to investigate the effect of temperature, salinity and algal concentration on the filter-feeding of the bivalves. The salinity ranging from 5 to 30 at the interval of 5 psu, four temperatures at 20¢X, 25¢X, 27¢X and 30¢J, and three algal concentrations of each Isochrysis galbana and each Chaetoceros gracilis, 104 , 105 and 106 cells/ml, were used. Algal concentration was measured each hour and each test run last for 6 hours. A peak appeared at the salinity of 20 psu in each clearance rate vs salinity curve and clearance rate decreased with increasing algal concentration; a peak also appeared at the salinity of either 15¡ã20 psu in the ingestion rate vs salinity curve; and ingestion rate and the amount of pseudofaeces increased with increasing algal concentration. Under the conditions of algal concentration 104 cells/ml and temperature range 20¢X~30¢J, a peak appeared at 25¢J in each clearance rate and each ingestion rate vs temperature curves, and the greatest peak of clearance rate was 1.13 l/h; and the amount of pseudofaeces was the greatest at 25¢J and 20 psu. The bivalves fed with Isochrysis galbana have greater clearance and ingestion rates but less amount of pseudofaeces, compared to those fed with Chaetoceros gracilis.