Useful Guide To Building A Reef

Posted by By Scuba Herald at 26 October, at 23 : 35 PM Print

Coral reefs die for many reasons, both from natural disasters and manmade pressures. A reef system that took hundreds of years to grow can be destroyed in a single day. When reefs die, fish populations disappear, fishermen lose their livelihoods, and tourists disappear. Whilst reef conservation is the most cost effective counter-measure, many believe that a more active solution is required. Successful artificial coral reef programmes have been undertaken in many destinations worldwide.

The following few basic steps will help you with a successful artificial reef project:

1. Planning is the most crucial aspect. Success will ultimately reflect the quality of planning and ongoing management.

First, determine the specific purpose of your project – creating a new dive spot, repairing existing reefs, or protecting endangered species.

Next, determine your budget; what you can afford will determine the options.

2. Now set up a project team with roles and responsibilities. Projects require reef monitoring and data collection programmes for at least three years. There are many tasks to do: project management, public relations, sourcing materials and labour, fish counts, water quality analysis, coral photo documentation, and security.

3. Site location – if you’re building the reef for diving then a reef of 10-30 metres depth is sensible. Depth will also be important to ensure the reef does not become a hazard to boats. Ecological characteristics that are conducive to coral colonisation, fish behaviour, sediment type and biodiversity are also all important factors. Others include environmental conditions such as currents and wave action, water quality, seasonality, and temperatures.

When considering a project to repair a damaged reef, it’s important to consider how the reef was damaged. Pollution, cyanide and over-fishing, and bleaching leave the reef framework intact, so reef recovery may be possible. Dynamite fishing on the other hand, destroys the reef and will prevent recovery.

4. Your main PR job will be to persuade the local authorities and public that the reef and its no-take zone are in the public interest. Often the way to do this is demonstrating it in monetary terms; by demonstrating tourism potential or fish population growth.

5. You should be aware of all the environmental and legal requirements involved in the preparation and placement of an artificial reef and should discuss these with authorities before starting.

6. The design, structure and stability of artificial reefs are obviously critical. Important aspects in targeting fish species include void space, shelter, bottom relief, reef height, light and shading.

Many popular reefs are made in the shape of a hollow concrete balls riddled with holes, or hollow concrete pyramids with triangular holes. Coral growth rates can be significantly increased by creating stable, spatial structures that are high above sediment to minimise burial or abrasion.

For one diving reef at Manado Tua Island, Bunaken, Sulawesi in Indonesia there are 500 square metres of ‘Ecoreefs’ – snowflake-shaped ceramic modules which will break down eventually leaving a natural reef behind.

7. Materials used to develop artificial reefs must be selected that create habitat for fish and invertebrates. Materials that pollute through leaching, weathering, or biological activity should never be used, nor those whose disposal at sea is prohibited.

By far the most favoured reef materials are concrete and limestone rocks. For simple, low budget, large scale sites they are good for coral settlement and growth. Moulded and manufactured reefs are also popular.

Ships are often turned into artificial reefs. Organisers clean the ships and passageways to make habitats safe for divers. A poorly prepared ship can contain considerable amounts of toxic substances and have a devastating impact on marine life.

8. Reef management and regulation involves the long, on-going task of monitoring, maintaining and safeguarding your new coral reef. Access to the reef must be controlled and fishing regulated. Buoys can be attached for divers to reduce anchor damage, but care must be taken not to create easier fishing conditions.

In Komodo , Indonesia, weekly patrols were set up to enforce the ban on destructive fishing practices. Dynamite fishing decreased by 75% and cyanide fishing and live reef fish trades also reduced.

9. The placement of artificial reefs results in the aggregation of fish. When there is no regulation of the fishery, an artificial reef may reduce local fish populations simply by making them easier to catch. For this reason we recommend that fishing be restricted to the outlying areas that the new reef can contribute to and support.

10. Transplanting corals from one reef to another has some obvious benefits as it can lead to an immediate increase in coral cover and diversity. It works well in areas that have poor coral larval supply or high mortality rates, such as isolated inlets and bays. Water quality will need to be good and the area needs to be free from big waves and strong currents.

However, transplantations are expensive if done on a large scale and cause the loss of corals from donor areas, as well as reducing the growth rates and fecundity of colonies due to stress. If a site is suitable for coral growth and has a good supply of larvae, it should be able recover naturally anyway, without the need for transplantation.

11. Conclusion – successful artificial reef programmes can and do make positive contributions. In Komodo, corals reached 60-80 cm in diameter after four years growth on an artificial rock structure. On the nearby untreated rubble fields, no change in coral cover was detected after six years.

In Sarawak, Malaysia, artificial reef balls have contributed to green turtle conservation efforts, where illegal trawling was decimating populations. The project started seven years ago to protect the nesting and swimming areas of the turtles, and has helped reduce the number of dead turtles washed up on the islands by 75%.

Jordan and Israel have become unlikely partners in an artificial reef project designed to provide alternate ecosystems in the Gulf Of Aqaba. In 2007 several huge concrete structures were lowered into designated zones, the structures containing pre-drilled channels into which the young nursed corals will be placed.

Your success will depend on your planning and preparation, making the best use of resources, and keeping fishermen away. One thing that no one can take away from you should your project fail, is that at least you will have tried and played your part in helping to preserve our endangered marine environment.

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