There is currently three methods commonly being used around the world PVC (polymerising vinyl chloride) nursing farms, the breeze block technique and in recent years 3D printing/ artificial reefs. It is the first two I’m going to be discussing in this blog post as they are now considered the traditional methods with the advancements of artificial reefs and modern technologies.
A PVC coral nursery/ frames is made out small samples or fragments of corals that are harvested from a healthy donor coral local to the area under the supervision of the D.O.E - Department of Environment, the fragments are then relocated and raised within the nurseries until they are large enough to then be out-planted back into the reef they came from or to creat the foundation for starting a new one. Corals are grown in these nurseries for about six to nine months before planting them in local sites. The coral fragments are placed in rows on PVC pipes that resemble a basic tree scaffold and are then hung from the branches using monofilament lines (fishing wire) these scaffolds are typically placed near other already existing healthy coral reefs as the area has been prove to be a good environment for coral to natural grow in. The PVC tree is anchored to a buoy so that it can move with wave surge and provide corals with better water circulation. This process has many advantages, particularly with it having a higher survival rate for corals then most past methods and providing a relatively low cost and simple technology for anyone to be able to attempt it. The factors that influence a nursery success include size, location, depth, design, and structure.
A breeze block or fixed coral nursery is created when small fragments of Elkhorn or Staghorn typically as they are the fastest growing corals in the world are then simply affixed directly to cement blocks or slabs using a ocean grade epoxy or monofilament lines (fishing wire). In more elaborate projects, holes are drilled or punched into the breeze block and the coral is then glued into it, or in some cases a PVC or steel grate is first affixed over the breeze blocks , and then the coral fragments are secured to that instead of the block. Generally, between 2 and 6 corals are secured to each block, which are then set down in a sort of pavement like style at the restoration site but some projects have begun to creat more reef like structures by layering and stacking the bricks to simulate a reef. The technique is quick and cheap, and is attractive to reef managers that are looking to create large projects in a short amount of time. However the problem with this technique is that a strong current or lose fragment has been able to wipe out theses nursery in one go so my work would need to have a deeper texture on it to prevent this.
As these two techniques are the most commonly practiced globally they give a great insight on what is needed to set up a basic coral nursery very quickly and cheaply yet not all aspects of these methods are the most effective and efficient as a simple strong current can destroy nine months work in one go.