The Life Cycle of a Clam

Clam larvae in the veliger stage.

Clams in the pediveliger stage that have develop

Post-set clams inside the hatchery.

Last week another clam spawn took place in the hatchery! Spawns are timed out so that the shellfish are at different points in their life cycles, thus requiring different care, tank space, and feeding requirements in the hatchery! In order to make sure there is no overlap, it is import to understand the different life stages! Let’s take a closer look at the life cycle of a hard clam! 

The life cycle of a clam.

Adult clams are mostly sessile, meaning they stay in one place. However, they don’t start out that way! Clams spend the beginning few weeks of their lives as planktonic larvae! After a spawning event, fertilized eggs undergo cell division after about 45 mins. After 12 hours, these cells develop into free-swimming trochophore larvae. After another 12 hours, their shells begin to form and the larvae enter a life stage known as the veliger stage. At this stage, the clams develop ciliated velum, which give the veliger its name! The ciliated velum are used for locomotion and feeding. After around 7-21 days, the veliger larvae develop a foot and enter the pediveliger stage. Soon after, the clam larvae will lose their swimming organs and develop siphons, which are used for respiration and feeding. This is called settlement, and in a hatchery setting, we call these newly settled clams post-set. The term post set usually refers to clams that have completed the larval stage, but are still inside the hatchery. 

Check out the video below to learn more about shellfish larval development from hatchery manager, Josh Perry!