Site choice and preparation
It is important to carefully select an appropriate location for a coral nursery site prior to setting up a nursery. Careful attention needs to be made to issues that could affect the success or failure of the nursery.
Here are some of the issues that were pertinent to the Phi PhiLey Island nursery. Although these are useful as an all-round overview of issues it should be noted that each site is unique and other issues may also need to be noted.
i. What was the existing natural coral coverage at the site? Were corals naturally growing there and what types of corals?
ii. What was the overall depth of the site? Was the location too deep?
iii. What was the possibility of anthropogenic activity affecting the nursery after setup?
Would boat traffic, tourism or fishing trawlers cause a problem?
iv. How accessible was the site? Was the site close enough to base to allow for easy maintenance?
v. How far away from the donor colonies was the site? Would the location mean transporting the fragments a long distance?
vi. What sort of coral species would be used in the site? How easy would they be to collect and was there enough to provide an ample supply of fragments without causing too much stress to the donor?
vii. How sheltered was the site from natural hazards, such as storms and waves?
viii. What was the rational behind making a floating coral nursery? *
*The site finally selected was adjacent to a commonly used dive site called Table Coral City. This dive site was affected by the 2004 tsunami and many of the table corals on one of the seamounts were destroyed. It was hoped that we would be able to restock some of the Table Coral City site with corals harvested from the coral nursery.
The Phi PhiLey Island coral nursery site was suitable for a number of reasons:
i. Natural corals are growing well in this part of the reef with a wide variety of scleractinian species. Moderate current meant a good supply of nutrients but at the same time not too strong to cause a problem to the nursery. Water clarity ranged from 5 – 20 meters, which provided ample light. Very little sedimentation had been noted.
ii. The site was not deep. A fringing reef gently slopes way from the island from 1 meter depth to approximately 10 meters where it encounters the sandy bottom. This sandy substrate finally reaches to about 20 meters, but requires quite some time before reaching this depth.
iii. An ample supply of coral donors was available within 10 meters to 150 meters distance from the nursery location Coral donors were growing from between 2 meters and 14 meters depth.
iv. The nursery site was situated close enough to the island cliffs to avoid the possibility of trawler fishermen damaging the nursery. The site is also less visited by snorkeling and dive boat operators, which might cause possible indirect or direct damage.
v. The site is within 40 to 150 meters of the final recommended transplantation sites once the fragments have successfully survived the nursery period.
vi. The site is located on the east-north face of Phi PhiLey which is protected from the summer monsoons and is affected little by storms coming from the east during the winter. This allows us to maintain the site all year round.
vii. The site is only 15 minutes away from our base office.