Planula larvae is the Latin name of baby coral. Coral reproduce either asexually and sexually. Coral species are hermaphrodites. It means they are both male and female. They can produce eggs and sperm. In sexual reproduction, sperm swims into the mouth of a polyp containing an egg and fertilizes it internally. The young polyp or planula larvae grows within the polyp. The maturing of planula larvae is called brooding.
Every year, colonies of coral reef release "fertilized eggs" into the sea. These eggs then grow and become baby coral which will be carried away by ocean current to far away places. If they land on hard surface rock or substrate they will grow well.
Majority of the coral reproduction occur in sea water. During this process, polyps release or eject eggs and sperm into the sea. The sperm will fertilize the eggs externally, i.e. outside the polyps.
Experienced scuba divers and marine biologist like to watch the event of how the coral polyps eject eggs and sperm into the ocean. This happens once a year.
Japanese National TV station used to broadcast this event as an educational program to elementary and secondary school students in Okinawa islands.
The showing of coral spawning on TV brings positive impacts. Japanese people and those who were watching the program could understand and appreciate the importance of coral reef to the environment and livelihood of mankind.
On the average, one kilometer of healthy coral reef can produce 15 ton fish which can be caught or harvested sustainably. Coral reef is an important source of food not only to marine animals but also to human being. Therefore, it is important for all of us to participate in the protection and conservation of coral reef. by Charles Roring in Manokwari West Papua Indonesia