Yesterday (September 19th), three of the six adult noble pen shells released a large quantity of eggs (measuring 40 to 50 microns) for the first time. We collected the eggs and distributed them into tanks with other pen shells to encourage the release of male gametes. During today’s examination, we observed fertilized eggs, and we are now monitoring their development.

The noble pen shell is a hermaphrodite, reaching sexual maturity between its first and second year, when it reaches a length of approximately 10 cm. In nature, their spawning begins as the sea warms in late spring. In our aquarium’s controlled environment, we gradually raised the water temperature by 1 °C per week, and gamete release was observed at 24 °C.

Very little is known about the noble pen shell’s life cycle since, as a protected species, breeding attempts were never previously undertaken. Only recently, after it became critically endangered, have some institutions begun trying to induce spawning under controlled conditions. However, no one has yet managed to complete its life cycle in captivity, though the pediveliger larva (120 microns), the last planktonic stage before transformation into a sessile phase, has been successfully cultivated.