Effect of environmental factors on the fecundity, hatchability and survival of snail Lymnaea (Radix) acuminata (Lamarck): vector of fascioliasis.

Lymnaea acuminata breeds round the year. The effect of pH, temperature, dissolved oxygen, carbon dioxide, light/dark period and clean/polluted water on the fecundity, hatchability and survival of young snails of L. acuminata were studied. It was observed that these environmental variant abiotic factors caused a significant variation in fecundity, hatchability and survival of young snails. Maximum reproduction of this snail was observed in the months of March to May. A significant positive correlation (p<0.05) between D.O. (3.1-7.7 ppm)/pH (7.01-8.96) of water with fecundity (6.0-196.33/20 snails), hatchability (54.69-96.91%) and survival (61.3-95.86%) of young snails was observed for each month and each interval of 24-72 h. In contrast, a significant negative correlation between dissolved CO2 (4.6-16.6 ppm)/temperature (16-37 degrees C) of water was noted with fecundity, hatchability and survival of snails. Percent hatchability in the eggs in different regimens of water was between 96.91-54.69%. The hatching period was prolonged (2-14 days) in snail exposed to different groups of water compared to the control group (2-9 d). This study conclusively shows that variant abiotic factors in different months of the year can significantly alter the reproductive ability and development process in the snail Lymnaea acuminata.