The male polyps start by slowly releasing sperm, looking like trails of smoke spreading into a fine mist over the colonies. When the female polyps sense the sperm they forcibly release big puffs of eggs. The big polyps can release several thousands in one go, while the smaller polyps squirt out a few hundreds or only tens of eggs. In this image you can see both trails of sperm surrounding the polyps at the top, and the small white dots are eggs that has spread out in the full body of water. Photo: Susanna M Strömberg.
During February we have had a few successful spawning events, with good fertilization. Eggs and sperm were released simultaneously in our aquaria and now we have several bottles with larval cultures. The larvae are soon ready to start descending to the bottom, searching for a suitable place to settle down. But first they need to eat! The coral larvae have an appetite for the same type of food as their parents, although in smaller pieces. Perhaps they benefit for other animals sloppy feeding? They eat fragments of small crustaceans (copepods) and other small stuff. We will test what type of food they need to be able to do the transition from planula larva to small polyp.
