What are the relationship between lunar cycle in bivalves?

Question

how new moon and full moon affecting bivalves reproduce?

Answer 1

If there was any effect at all, it would just be the tides.  They are related to the moon's position around the earth and so, would correspond with phases.  But the phase correlation is not causal.  It's only the gravity that counts.  The most important factor in tides is the position of the moon as the earth rotates each day.  The position of the moon in its orbit, or its phase, affects the relative difference between high and low tides, ie: spring tides and neap tides.  

If you're suggesting that there is something mystical or unknown about the effect of the full moon or new moon, as in many old wives' tales, there is no such effect.  Like some people will tell you that more crimes are committed on the full moon or more babies are born.  Some will tell you its important to plant potatoes on the full moon.  None of these are true.