How do Clams Multiply?

[Hondo]

Just wondering how they reproduce? Do you need two clams for this to happen and does it happen in home systems and how often and how many offspring?

[herefishiefishie]

Clams are broadcast spawners, and two or more (of different genders) are needed to do this.

Sometimes clams of adult size are intentionally stressed to induce spawning.

To have a clam spawn in the home aquarium, I think, is a rare event... and that's a good thing. In an enclosed space such as a fishtank, thew clam's copious spawning material would choke it and perhaps everything else in the tank.

[aharmer]

I just wanted to add that clams are protandric hermaphrodites. This means that they mature first as males and then after a few more years they develop the ability to broadcast eggs. They avoid self fertilization by broadcasting sperm first followed shortly by eggs. On top of that the presence of gametes in the water causes other clams that are ready to spawn to release.

[OrionN]

Clams do not have any mechanism to prevent two or more sperms fertilize one egg. Because of this reason, having successful spawn in home aquarium is next to impossible. Multi sperm will fertilize one egg and thus will not developed.

[galleon]

The phenomena Minh refers to is known as polyspermia. The other problem that contributes to polyspermia is is the copious amounts of sperm broadcast (sperm before eggs), as you know, the ocean is quite a bit larger in volume than our systems. It is this problem that forces hatcheries to severly dilute sperm concentrations when fertilizing a batch of eggs before sending them to the settling systems for cleavage.