These characteristics make it easy for commercial and recreational clam diggers to tell the two species apart. Breeding occurs between May and September and is closely associated with rising water temperatures. A temperature of 55 F is believed to be required to trigger spawning. The sexes are separate in razor clams. In breeding, eggs and sperm are discharged onto wet sand and into sea water.
Fertilization occurs by chance.
Where the razor clam s reproductive cycle lacks efficiency, it compensates with numbers. Although an exact count of the number of eggs contained in a female razor clam is not possible, some researchers have estimated that number at somewhere between 300 thousand and 118.5 million. The larger the female razor clam, the greater the number of eggs produced. It goes without saying that the chance of survival for an individual egg is very, very low. The microscopic larvae bear little resemblance to parent clams.