Published online by Cambridge University Press: 24 August 2009
Demand of the construction industry for coral rock in the Maldives will soon reach the limit of supply capacity using existing collection techniques. It is estimated that, at the current rate of consumption, the supply of living coral rock from inner atoll ‘faros’ in North Malé will be exhausted within 30 years. Current mining practice has already necessitated the collection of living coral rock from outer atoll ‘faros’ which actually protect the integrity of the islands against the erosive influences of monsoon storms.
Biological surveys of mined sites (compared with controls where no mining activity has taken place) indicate a dramatic reduction in coral variety and abundance and in some cases an almost total depletion of living coral after mining. At intensively-mined sites, diversity and abundance of coral-reef fishes is also markedly reduced, with some reef species commonly used as baitfish entirely absent. The time taken for reefs to recover from mechanical damage has been shown by other research work to be extremely variable, with some cases showing no recovery in some circumstances. Shallow-water reefs that have been colonized by slow-growing ‘massive’ corals, such as those which have been mined in the Maldives, may take a minimum of 50 years to recover to their former state—under optimum conditions.
Observations on mined reefs in the Maldives show that recovery over the last 10 years has been minimal, and therefore suggest that recovery times may be much in excess of 50 years. Indeed many of these reefs may not recover at all unless some attempts are made to re-establish corals at these sites. It is also clear from the study of reclaimed and dredged sites and those where less-intensive mining has taken place, that regeneration of corals is occurring. It is quite probable that the rate of recovery is dependent on the intensity of the disturbance which initially took place.
Alternative building materials are available in the form of concrete blocks. Use of these blocks is more cost-effective than use of coral rock; however, there is a lack of any quality control, which would be needed to promote the widespread use of concrete blocks as a substitute for coral. Recently, recommendations have been approved by the Government of Maldives for the execution of a feasibility study on mining an inner atoll faro which could potentially provide building material for as long as the next 500 years.