Transplantation of hard coral fragments of branching species was tried in the Philippines during the 1980s to test whether the technique will work to rehabilitate degraded reef systems.
Small fragments broken off from healthy coral colonies found in the immediate vicinity were glued to the hard calcareous substratum with cement or epoxy. The fragments were observed to grow slowly.
Coral transplantation, at first glance, would seem to be a solution to the problem of coral reef degradation, and some people, including biologists and government officials, concerned with the environment, recommended it.
But a scientific analysis of this procedure gave rise to many questions, and the conclusion was that coral transplantation is not a good method for coral reef restoration. It would be better to put more human effort and more funds on protecting existing coral reefs of the country as only about four percent of our 25,000 square kilometers of coral reef are currently protected.
There are a number of reasons why hard coral transplantation, which could require substantial funding that could be put to better uses, will not solve the coral reef problem:
First, there are not enough healthy coral colonies that can supply the transplants because less than five percent of coral reef sites explored remain in excellent condition, that is, having at least 75 percent live hard coral cover. Most excellent reefs exist in remote areas. The majority of reef sites surveyed have been in various stages of degradation.
Second, coral fragments to be used as transplants usually come from branching corals. These should be transported from source reefs to transplantation sites preferably under water, and the required logistics to ensure that the transplant materials remain alive while being transported to the transplant sites are complicated and risky as to be impractical.
Third, the transplanted material may not survive in the transplant sites for various reasons. The risk of non-survival needs to be known. Even if this risk is known, it must be empirically demonstrated that the biomass of the surviving transplants is greater than the biomass of the fragments if they remained in the source colonies.
Fourth, removing a portion of a coral colony for transplantation does not increase the genetic diversity of coral population because the process is essentially asexual reproduction. Genetic diversity and heterogeneity occurs in a sexually-reproducing population and results in genetically vigorous individual colonies.
The best way to conserve coral reefs is to treat them as an ecosystem, where all of the ecosystem components (biotic and abiotic) are protected from pollution and extractive exploitation, as in no-take marine reserves.
In these reserves, all associated species function normally and contribute to the well-being of the whole ecosystem. Only by learning how nature functions can human beings derive benefits from coral reefs.