22/09/2019
In November 2018 we installed 80 metal racks on the substrate at depths ranging from 3.5 - 9.5 meters (low mean tide). The location is just north of Loh Samah Bay on a reef flat and gradual sloping reef. The site was originally covered with many large colonies of acropora corals but they were 100% devastated by the coal bleaching event of 2010. This location appeared to be a suitable one for transplanting acropora fragments from the floating coral nursery given that acropora corals were originally the dominant species in that area.
Each metal rack can hold between 13 and 16 coral fragments. A total of 1066 corals were attached between November 2018 and January 2019. There are currently 918 coral fragments remaining with a total of 86.12% surviving.
Coral fragments are growing well on the racks. Overall the racks seem to be providing a suitable way to fix the corals close to the bottom and since the fragments are elevated around 8 inches above the bottom it prevents loss due to sedimentation. Throughout the year, currents and tidal movement cause the level of sand to rise and fall. This can cause a problem if attaching corals close to the benthos. Eventually the corals on the racks will grow to a size that will too big to be supported by the metal racks and they should collapse to the benthos, but by that time they will be large enough to be self sufficient. Eventually the coral racks will rust away and only the corals colonies will remain.
Boats anchoring in the area have dragged a few of the racks away from the site leading to a loss of 13 of the corals. This is the 2nd time this has occurred. One of the racks was discovered 20 meters away although it had landed up the correct way and all the corals were still live. Another rack was discovered upside down next to it’s original position with the attached corals in the sand although they were still alive which suggests it had only been flipped over recently. In addition there was plastic trash, string, bathing towels and also a large fishing net discovered that was covering some of the fragments.
Corals that were installed in January 2019 on the floating nursery at Viking Bay seem to have nearly fully recovered from the bleaching that started a few months earlier. From a total of 840 fragments installed from the Garang Heng site, 713 fragments remains (total 84.88% survived). From the 850 fragments installed from the Tonsai bay site, 699 fragments remain (total 82.24% survived). Overall out of 1690 fragments originally installed at the beginning of 2019, 1412 fragments so far survive (83.55% survival)
9 Floating coral trees were installed and 426 fragments were attached in January 2019. Currently 321 fragments remain (75.12% survived). There has been a loss due to the string which attaches the coral to the trees, snapping. A stronger filament next time should improve the overall survival rate.
