"Initially, Bli and I (I Made Dharmajaya, WWF-Indonesia) were just taking an afternoon walk to Batu Putih Beach. Then the idea came up to build fish houses with rock piles to restore the damaged water area," explained Denny Lalitan, a member of the Alor Regency DPRD.

That afternoon (08/13/2018), we were joined by Om Denny - as this environmentalist is usually called - as well as the Alor Marine Fisheries Service, Tribuana University Kalabahi, Alor Tourism Office, and the local community gathered together at Batu Putih Beach, Alila Timur Village, Kabola District, Alor.

This time, they did not only relax to enjoy the beautiful scenery of one of the favorite tourist attractions in Alor Regency, but together they took the action of returning stones (dead coral reefs) to the sea.

Young and old, father and father, and even small children worked together to lift the stone into the sea. The rocks were to be returned to the sea, to be stacked into a rock pile on the seabed (rock pile). The rocks are first mobilized one by one and lifted into a motorized boat, then thrown to the bottom of the water.

SCUBA divers and traditional divers who were already at the bottom of the water then picked up and arranged the rocks to be stacked with dimensions of 3×1.5×0.5 cubic meters. The whole process was carried out for approximately 4 hours starting when the sea began to rise at 12:00 WITA. There were 2 SCUBA divers and approximately 4-5 traditional divers involved in making this rockpile.

Success of the Rock Pile

In 2013, this method was also used in underwater rehabilitation in the waters of Marica Village, Kangge Island. The growth of coral juveniles reached 12 cm in 5 months on limestone substrate.

However, unlike Kangge Island, this time the rock piles were constructed using (dead) coral reefs that were previously lifted from underwater to land and collected by the community. Currently, chunks and broken coral, gravel, and sand are still collected by the local community as building materials.

The materials are used as components to build private houses, as well as being sold outside. One ret (unit for a collection of stones) is valued at Rp 250,000 for large boulders, Rp 350,000 for gravel and Rp 500,000 for sand.

"Although declared threatened due to bombing and mining, in general the condition of coral reefs in the Batu Putih coastal area is quite good. It can be estimated that rock piles in this area can be overgrown with coral reefs within the next 2 years," said I Made Dharmajaya - Alor-Flotim MPA Coordinator for WWF LSS.

Diverse coral reef conditions can provide a natural "seed" supply of coral animals. Corals that are spawning in the water column will shoot their male cells and eggs into the water column, then the juvenile cells that have grown and become larvae will attach to the rock substrate.

Based on experiments by Fox et al (2005) in Komodo National Park, coral larvae tend to grow more easily on rock piles because it is the most natural substrate. This is one of the considerations for choosing the rock pile method, compared to man-made processes such as coral transplantation.