How do clams and other shellfish get born or made?

Question

How do clams and other shellfish get born or made?

Answer 1

It depends a little on the species.  Marine bivalves, including clams, mussels, oysters, scallops, spew their gametes out into the water.  Usually at low tide, so the water is lower, increasing chances of fertilization, a whole bunch of males & females release their gametes into the water so they're all sitting in this big pool of sperm and eggs.  Fertilization occurs in the water.  The embryos are transported by the currents and they develop into feeding larvae (called a veliger) that drifts around in the currents for weeks to months (depending on species).  Once they are old enough and they sense a chemical cue that the place they're at is a good site, they settle to the bottom and metamorphose into a juvenile.

Freshwater bivalves reproduce similarly, but in many species the female actually broods the eggs inside and releases the larvae.

In other shellfish, like crabs and lobsters, they actually copulate.  The males transfer a spermatophore (a big package of sperm) to the female.  She hangs onto it for a little while and then when she is ready to extrude eggs, she uses the sperm in the spermatophore to fertilize them.  Crab and lobster females keep their egg masses under their bodies until their larvae (zoea) are ready to be released.  Then they drift with the currents and eventually get washed in shore somewhere to settle and metamorphose.  Lobster females keep their eggs for about a year, but most crabs only keep them for a few weeks-month.

Answer 2

um.... once heard on this show called dirty jobs that they are just an accumulation of bacteria left in the shell i don't know how accurate that is because we eat them