Nursery Set Up
15mm pvc piping is used to create the frame of the racks and this is then covered my using plastic meshing attached by cable ties.
Cut lengths of flexible plastic tubing. Each tube should be about 8cm long. Cut one end straight and the other end pointed. The pointed end will help to insert the tube into the plastic mesh.
Numbered tabs were prepared to identify the control fragments. Each tray will have about 10 control fragments.
Qualified divers that have good buoyancy control should only attempt coral collection. We select colonies of a reasonable size depending the amount of fragments to be collected. It is recommended to have one person for cutting and one person for handling the baskets.
Fragment lengths depend on the coral species. However for acropora branching species we cut fragments about 60 mm in length. This allows for about 15mm to be inserted into the plastic tube.
Gently grip the fragment with the wire clippers. It is better to snap rather than cut, and give a twisting action to the clippers. We work around the coral colony so as not to collect all the fragments in the same part of the colony.
Clean hands prior to handling corals. Remove any sunscreen, or detergents.
Handle the coral fragments as little as possible.
Separate corals of different colonies and species. Do NOT mix fragments from different colonies.
Once the corals have been brought to the boat keep the corals out of direct sunlight.
Keep the corals in clean seawater and regularly change the water.
Avoid damaging the coral polyps by squeezing the fragments too hard.
|Placing in Racks|
Insert all the corals for the one rack into the plastic tubes. Ensure that the fragment is tightly inserted.
Do not insert the tubes into the racks until all the fragments have been inserted into the tubes. Once in the tubes keep them immersed in seawater.
The base of the coral may need to be trimmed using the wire clippers so as to insert it into the tube.
Insert the tubes into the racks. Try to keep the lines of corals uniform. This will assist monitoring the fragments later.
Place marker tags on the first ten fragments. Get into the habit of marking all the fragments using the same method. We always mark our fragments from left to right (E.g.: AC1 to AC10). When we monitor our fragments we always measure and photograph the fragments from left to right.
Ensure the tags are tightly attached.
Once a rack is completed hang it off of the side of the boat until all the other racks are completed.
In some instances it may be useful to add a drop of superglue to the base of the fragment. Avoid contaminating the upper part of the fragment.
We usually manage 60 acropora fragments per rack and less for the larger coral species.
We have found that Montipora sp. fragments are readily available on the reef and make an ideal subject for growing on the nursery.
Trim the montipora fragments into pieces about 40mm 2
Drill two small holes through the fragment using the cordless drill.
Thread a 20 cm length of telephone wire through the holes.
Thread an 80 cm length of fine string through the holes.
Attach the fragment to the rack by use of the telephone wire.
The string will be used at a later stage once the montipora fragment needs to be attached to the reef.
Use the telephone wire to attach the marker tags to the tubes or directly to the rack.
Tag the corals in order.
It is useful to number both the rack and the fragment (For example fragment AC 6.7 2009 refers to fragment number 7 in rack number 6 from the 2009 nursery).
On the present nursery we have the capacity to manage 1680 acropora fragments or less if managing larger coral species.
|Monitoring and maintenance
Maintenance of the nursery needs to done before algae cause damage to the fragments. The time frame will depend on how much sedimentation and algae growth in the area of the nursery.
At our site we need to clean the algae off at least every 5 weeks or less, otherwise, we find that the algae growth has grown up onto the fragment.
Periodically we need to remove any crustaceans since these increase the weight of the nursery and can cause it to sink. This also means removing the growths from the ropes.