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Concept On Artificial Reef Development

I. INTRODUCTION:

A. Definitions

An Artificial Reef (AR) can be described as a collections or assemblage of solid structure placed together in an aquatic environment to provide or improved fish habitat.

Terms such as artificial fish shelter, man-made fish habitat and fish aggregating device are sometimes used for artificial reefs.

B. Background

The concept of the AR is not entirely unknown in the Philippines. In estuarine areas and tidal flats, fishermen file bamboo brushes/stems or tree branches (rama or goo) to attract fish thereby creating artificial fish habitat. While in relatively deep areas, coconut fronda (payao) are used to create shelter for food fish thereby attracting the capture of their predators (e.g. tuna and jacks). The above methods although proven very effective for a supplemental fisheries resource are but temporary, lasting only for a few weeks or months.

In areas where there is an absence of natural fish habitat (e.g. coral reefs) or where the reefs are degraded, submerging an AR using durable materials which will last for long periods can provide fish and other organisms a suitable shelter. This man-made fish habitat will in turn become a supplemental fishing resource. The development of ARs which have been done on many countries (eg. USA, Japan, Australia, Taiwan, Malaysia) has proven to provide more food for the multitudes.

C. Rationale for Establishing ARs

The pressure of an expanding population have caused the need for more proteins and this has led to the over exploitation of our sea resources. Knowing this problem, it is now time for us to make an effort to provide for the future of our children. Constructing ARs is one way of obtaining more food from our seas.

Although AR is one method that has been shown to increase fisheries production, it has not been sufficiently developed in the Philippines. One reason might be that the Philippines has vast areas of natural reef that still provide good fishing ground. Though this might be true to certain extent, many people specifically concervationists show a great concern over the degenerating condition of many of our reef areas due to pollution, siltation, coal collection and destructive fishing methods. Because of these problems, fishery scientists have researched on the possibilities of increasing production of the sea and making the fish and other commercially important marine organisms more easily available to local fishermen in a much less irrational way then by destructive fishing methods. Within an AR, elements responsible for the high productivity of coral reef areas are being duplicated thereby creating an environment that will provide many economic benefits.

II. Benefits derive from ARs

1. ARs serve as nursery areas and shelters which increase the survival rates of juvenile fishes and invertebrates
2. Serve as aquarium fish attractors
3. Serve as commercial and recreational fishing ground or can serve as recreational diving areas.
4. Facilitate solid waste disposal, depending on the material used.
5. Help decease fishing time, effort and energy by concentrating fish in confined areas thus eliminating search, and
6. Act as supplemental fisheries resource

III. TYPE OF ARS

The type of ARs varies according to function, purpose and kind of material used for construction.

1. According to material
There are many different materials available including tires, trucks and cars, building rubble, quarry rocks, cement blocks, culverts, sunken boats or ships, and bamboos. The type of material to be used is determined by its local availability. Careful consideration should be given to the materials chosen. They should be large, durable, suitable for algal and invertebrate attachment, in expensive and easily handled at sea.

• Tires – discarded or old tires are the ones used in the Philippines. They are sturdy and relatively durable. They are usually acquired through donations from tire and bus company motor pools.
• Bamboo – this is another material being used. Though not very durable like the tires, they are readily available in many coastal barangays, less expensive and commonly handled by local fishermen.
• Old cars, boats or ships – these would be most impractical for the Philippines because of its high cost of construction and low durability although many sunken ships had been shown as very effective fish habitat.
• Cement blocks, Culverts, rocks – these makes excellent habitat but the coasts of material, handling and construction is expensive.

2. According to design

• Low profile/relief – the low profile/relief AR can have effective fish attracting properties mainly where fishery is for demersal species (eg. groupers, snappers, grunts). This design can be good for relatively shallow barren areas.
• High profile/relief – this has an essential higher vertical coverage or height that the above and thus could attract both demersal and pelagic fishes. Its effects on navigation should be taken into account.
• Low profile or high profile AR with floating structure – floating structures (eg. payao) have been shown to attract pelagic fishes. These structures combined with the low or high profile AR would become very effective in attracting demersal fishes and enhancing the pelagic stocks present in the area.

IV. CRITERIA FOR SELECTION OF ARS

• The site should be greater than ½ mile away from natural reefs.
• They should be near an alternative food source (eg. sea grass beds)
• They should be constructed on a flat barren area of relatively good visibility.
• They should be at depth protected from wave action but still accessible to local fishermen (eg. 50-80 ft)

V. OTHER CONSIDERATIONS IN THE ESTABLISHMENT OR ARS

• Community involvement is a must. It is important to have the cooperation and understanding of the local fishermen to insure its success.
• Pre-construction dialogues, lecture, orientations thru slide seminar presentations among the local fishermen should be conducted.
• A dive team expertise in AR construction can help with site selection, construction, monitoring and research.
• Establishment of ARs should have specific standards and should be misused just to serve as promotional gimmicks for interest group.
• AR project must be based on the right perspective and understanding of its concepts. They should be considered as habitats where fishes and other valuable marine organisms may seek shelter and food. They are certainly not meant to grow corals or to replace the natural reefs.

VI. Management of ARs

The ARs presence in the marine environment is a modification of the latter. Much of it depends on the basis of the management of the ecosystem by man for man’s needs.

• Management scheme should be viewed on a perspective of biological productivity so that it can be related economic progress thru time.
• The understanding of the ARs needs preliminary baseline data of the community. Thus, proper monitoring of the project would be important. Observations such as (1) estimates of fishes and invertebrates (secondary productivity) and plants (primary productivity); (2) sediment analysis; (3) temperature and clarity; and (4) AR changing conditions are important in order to understand the development of the marine community involved.
• With the proper understanding of the ARs attracting capacity, we can have sound biological judgments like the time to harvest fishes, the types of fishes to be harvested and the methods of harvesting them.
• Coordination with the appropriate government Bureau or agencies engaged in AR development with regards to AR construction should be made in order to properly monitor AR development projects in the country.
• Without proper coordination and comprehensive planning between the national and local government, national and regional fishery biologists, commercial and sustenance fishermen and interested private groups or individuals, there would not be a successful AR building effort. Careful planning, cooperative efforts and proper coordination of many individuals and services are the keys to a successful artificial reef development program.

Produce by:

Coral Reef Research Unit, Research Division Bureau of Fisheries and Aquatic Resources.

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