Fisheries Technologies for Developing Countries (1988) / Chapter Skim
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3. Artificial Reefs and Fish Aggregating Devices
3. Artificial Reefs and Fish Aggregating Devices
Pages 85-114
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From page 85... ...
Artificial reefs are man-made or natural objects specifically placed to attract fish, provide or improve fish or shellfish habitat, and increase fish biomass locally. Extremes range from traditional designs frequently made from local scrap materials to modern Japanese-style artifical reefs that are highly sophisticated modules built of concrete, fiberglass, or steel.
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From page 86... ...
.__ _ _ . 1 Benthic ' Low Profile Bottom lo= FIGURE 3.1 Depending on the marine environment and the target fish, high- or low-profile benthic reefs, or coating or midwater fish aggregating devices may be used to attract fish and facilitate their capture.
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From page 87... ...
If possible, the site should be near fishing villages to simplify the logistics of installation and to minimize time, travel, and fuel consumption before the fish can be processed on land. An artificial reef should not be placed in commercial fishing areas unless it is specifically intended to close an area to these operations.
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From page 88... ...
Ivory Coast fishermen place coconut palm fronds in shallow water to attract shrimp. While one person drags the frond to shore, another follows with a scoop net and gathers the fleeing shrimp.
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From page 89... ...
Horizontal crossbeams lashed on with nylon twine hold the tripod together. Villagers hang fallen coconut palm fronds from the horizontal beams.
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From page 90... ...
In the Gulf of Batabano on the south coast of Cuba, fishermen from local cooperatives have placed some 120,000 lobster shelters and annually harvest 7,000 tons of lobster from them. Shelters are increasingly being constructed of ferrocement, since it is illegal to cut mangroves.
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From page 91... ...
Rubble and Rocks The traditional Japanese artificial reef involved simply placing shore or quarry rocks at shallow depths as a way to enhance fishing grounds. In northern Japan, fishermen have placed rocks to enhance kelp production since the late 1600s.
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From page 92... ...
92 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES FIGURE 3.3 Mexican fishermen construct a lobster shelter similar to those used in Cuba.
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From page 93... ...
Tires In many developing countries, old tires have a high economic value and, therefore, may not be appropriate for artificial reefs. However, tires do not disintegrate in seawater and are fairly easy to handle.
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From page 94... ...
FIGURE 3.5 Scrap tires can be used to make artificial reefs, but unless firmly ballasted, they will be swept away by waves, currents, or storms.
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From page 96... ...
An igloo-shaped unit has given encouraging results in the Chesapeake Bay in the eastern United States (figure 3.9~. Damaged concrete pipes have been used for artificial reef construction in Hawaii.
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From page 98... ...
The primary objective of the artificial reef program in the Gulf of Thailand is to enhance fishing grounds for artisanal fishermen. Rayon g was the site of the first reef, which was constructed in 1978.
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From page 99... ...
The hypothesis is that the artisanal fishermen's catch using traditional fishing arts will increase in areas where trawlers are excluded. In other areas, trawler exclusion modules are also being combined with groups of artificial reefs.
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From page 100... ...
In a Florida trial, ah of the components for the FRP reefs were shipped from Japan and assembled at dockside. The units were : ~~_~ FIGURE 3.11 Concrete cubes are fabricated for an artificial reef in the Andaman Sea, Thailand.
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From page 101... ...
Preliminary analysis of the survey data for the first 18 months indicates that the FRP reefs appear to attract and retain a significantly greater total abundance and diversity of fish, and have much richer epibenthic communities than the culvert reefs. In particular, the FRP reefs have been more effective for larger midwater predators such as the greater amberjack and king mackerel, and seem to have a larger number of the bait fish and juveniles on which these predators feed.
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From page 102... ...
Surface and midwater attractor reefs or fish aggregating devices capitalize on this behavior. These may be used alone or in combination with benthic artificial reefs.
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From page 103... ...
FIGURE 3.14 When drilling rigs become obsolete as oil producers, they can become fish producers. Tenneco Oil is relocating steel towers from such a rig for use as artificial reefs off the Florida coast.
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From page 104... ...
In the Mediterranean, near Malta, dolphin fish and pilot fish appear from August to December. Both of these species seek shelter under floating objects.
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From page 105... ...
anchored in deep water in the Philippines to attract tuna.
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From page 106... ...
Modern FADs Recent innovations in FADs improve on the durability of the traditional structures by using plastics and artificial fibers. Used mainly to attract migrating pelagic species, these midwater or surface FADs consist of the main fish attractor, a mooring line, a concrete or sandbag anchor, and a surface or subsurface buoy to suspend the FAD.
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From page 108... ...
In Barbados, a project is being designed to shift the fishing effort from demersal species in an overfished traditional fishing area to migratory pelagic species farther offshore. In recent years, more than 300 surface FADs have been deployed in the central and western Pacific and Indian oceans Much of the development work for these structures occurred at the Southwest Fisheries Center Laboratory in Honolulu, Hawaii.
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From page 109... ...
Other work in Hawaii has involved FADs with several different designs (figure 3.19~. Tire-based FADs were made from discarded sugarcane truck tires filled with polyurethane foam.
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From page 110... ...
It is believed that this configuration will better tolerate strong surface currents and storm waves.
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From page 111... ...
User conflicts may result over the commercially valuable catch at the reef site or from a decreased stock in adjacent fishing grounds. Reef construction costs vary widely with location and type of construction material.
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From page 112... ...
1982. Structured flotsam as fish aggregating devices.
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From page 113... ...
1985. What do natural reefs tell us about designing artificial reefs in Southern California?
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From page 114... ...
. Southeast Fisheries Center, NMFS, 75 Virginia Beach Drive, Miami, FL 33149, USA (J.
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