WHY ARTIFICIAL REEFS?

Artificial reefs are man-made structures placed usually on the seabed and constructed primarily for several practical reasons. In many countries artificial reefs have been built for the purpose of aggregating fish for easy capture and in several instances for increasing the productivity of fish and other organisms in the surrounding coastal waters.

Although there are dissenting views; generally fish and other marine organisms are closely associated with natural or artificial underwater structures. In addition, even drifting logs etc., act as Fish Aggregating Devices (FDA’s). Artificial reefs have been successfully utilised as habitats for fish, oysters, seaweeds, lobster, abalone and to protect shore lines. In several instances they have been used to prevent the entry of trawlers into specific areas like traditional fishing grounds or sensitive areas. A more recent development is their use for promoting tourism and sports-fishing. Brunei Darussalam with the assistance of Brunei Shell has utilized redundant oil rigs since 1988 for building artificial reefs with great success. It is of interest to note that the Fisheries Department of Brunei Darussalam was awarded the coveted first prize (Gold Award and 10,000 Brunei dollars) of the Civil Service in 1994 for its Artificial Reef Programme named “Rigs to ReefS"

Shipwrecks too, emulate artificial reefs and attract fish. In many countries the locations of shipwrecks have remained a closely guarded secret among the few traditional fishermen who fish these.

Scientific investigations on the use of artificial structures as FDA’s are more recent. However, Japanese scientists indicate that sunken ships were productive fishing areas and fished during the Kansei Era (1789-1801). It has been acknowleged that artificial reef building was pioneered by the Japanese about 200 years ago. They used wooden structures to make man-made reefs to emulate a wooden shipwreck that served as a source of fish for years before it disintegrated and failed to aggregate fish. Since then, artificial reefs have been made from a variety of materials such as discarded tyres, granite rocks, old car bodies, plastics, concrete and even fibreglass and to serve more diverse purposes. Japan is still the leading country that uses artificial reefs to increase its fish production.

Artificial reefs contribute to the enrich­ment of marine life by providing shelter from strong currents and protection from predators. They also provide firm substrate for the attachment of organisms that serve as food for fish and other marine animals. There have been several instances where artificial reefs have served as breeding and nursery areas for different kinds of organisms and have also functioned as core areas for the production of new recruits of economically and environmentally important marine life. They also offer a visual, tactile or even auditory reference point for many pelagic fishes that aggregate around them.

As with many other human interventions with natural environments there are dissenting views on the use of artificial reefs for the enhancement of marine life. One should undertake a holistic cost-benefit analysis taking into account socio-economic as well as environmental aspects to arrive at a decision to build artificial reefs.

We should note that artificial reefs will never be able to perform the many complex functions of a natural coral reef. There are instances where artificial reefs have provided a base for the development of coral and at times even small coral reefs.

It is unwise to build artificial reefs at the expense of natural coral reefs. However, when carefully designed and strategically located on the seabed, artificial reefs have been able to emulate one of coral reefs more important functions of fostering marine life. There are several instances where they have helped to provide alternate fishing and tourist areas, thereby reducing excessive pressure on vulnerable coral reef ecosystems. It should be emphasised that protection of natural coral reefs should be the priority and not the favoured opt

15 May 2011

Prepared by:

M.W.Ranjith N. De Silva B.Sc. (Ceylon), Ph.D. (Liverpool)

OWSI #35583

Email: [email protected]

May 2011