Next round of reef restoration with larval propagation

Soon it will happen again: a large part of the stony corals around the Banda Islands will release matured eggs and sperm into the water. This impressive phenomenon takes place 1-2 times a year and if you go diving in the dark, you can observe what almost looks like a snowstorm underwater.

With BandaSEA and funded by the German Foundation for Marine Conservation, we have been supporting two students from Banda Naira (Farista and Rifaldi) since the beginning of the year, who have made this phenomenon the subject of their bachelor thesis.

Farista is investigating which coral species spawn on how many days after the full moon. Detailed information on this is particularly important in order to use coral spawning as a method of reef restoration. She has already been able to identify the first exciting results.

Rifaldi is looking at whether it is possible to grow coral larvae from eggs to accelerate the establishment of new corals on the reef, even with the facilities available on the Banda Islands. This works well in Australia's Great Barrier Reef and on a few Philippine reefs, for example. The method is particularly promising because it promotes genetic diversity compared to conventional restorative methods and is extremely gentle on existing coral populations. Only a tiny fraction of the eggs are used for restoration. The majority contributes naturally to resettlement. In addition, specific areas in the reef can be stocked with coral larvae. For example, one can accelerate the recovery of areas in the reef affected by past bleaching events.

Both students use self-made egg traps for their project. These consist of funnels and plastic bottles (which are even upcycled). Starting with the full moon, the traps remain in the reef for a week. Every morning the students dive down to the traps to check if there are eggs in the traps. However, since the eggs need to be particularly 'fresh' for larval growth, they also go out for night dives on the 3 nights with the highest chance of mass coral spawning. Tomorrow it starts and we are already excited. At the end of the week we will report how it went.