Diving Indonesia Periplus Adventure Guid. David Pickell

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      To a fisherman, who works a long, hard day to bring a few fish to market, the appeal of bombing is obvious. Unfortunately, the impact on the reef is disastrous. Not all the dead fish float, of course, and method is very wasteful. But the most damage is caused by the destruction of the coral by the blast. Fish will essentially reproduce to fill the environment. Coral is the environment.

      Flourinshing Cottage Industry

      According to a report by Stephen Nash of the World Wildlife Fund for Nature, an old Allied ammo dump in the Padaido Islands has been the source of a cottage industry supplying the fish bombs used in Biak and the Cenderawasih Bay, and may supply powder to markets as far away as western Indonesia. The report was written several years ago, and at the time the supply of easily-found shells was running out. But the author feared that scuba gear, brought to Biak to equip collectors of tropical marine fish, would make accessible new supplies of bombs.

      The Padaido islanders are masters of the very delicate art of live bomb recovery. The shells are found by dragging the sandy bottom with a piece of iron tied to a rope. When it is felt to hit something hard, a diver puts on goggles and dives to the bottom—18 meters—ties the bomb to the rope, and returns to the surface. Then the bomb is hauled up. Once on land, the bomb is carefully opened, and the priming mixture and cordite are extracted for packaging and sale.

      The trickiest part of building the fish bombs is constructing the fuse, which is made of the flat, malleable aluminum from a tube of toothpaste. Priming mixture is "diluted" with crushed matchheads and the aluminum sheet is rolled around it like a cigaret. The aluminum makes the fuse waterproof; heat and combustion gases keep the water from rushing in the open end. Different lengths of this waterproof fuse are used depending on how deep the fisherman wants the bomb to go before exploding.

      The fuse is attached to a standard beer bottle—or a large ale bottle, or a small medicine bottle—with coconut husk rope and pitch. The whole package is stuffed into a papaya, and thrown over board. According to the report, fish bombers off the south coast of Biak near the airport time their bombs with the noisy arrival of the Garuda flight, which effectively masks the explosion.

      Today, the supply of cordite and gun-powder has for the most part disappeared. Unfortunately, the clever fishermen have now discovered how to make bombs using ingredients found in widely available chemical fertilizers.

      — David Pickell

      A barrier reef that forms around an island is sometimes called an "almost atoll." There can be multiple barrier reefs, extending outward like ripples, and the large lagoon behind a barrier reef can harbor small patch reefs and sandy cay reefs.

      Atolls. Some 425 of these characteristic circular reefs, with a large central lagoon, have been recorded throughout the tropics. The vast majority (more than 300) are in the Indo-Pacific. The largest is Kwajalein in the Marshall Islands, which forms an oval 120 by 32 kilometers.

      The largest atoll in Indonesia—and the third-largest in the world, just 20 percent smaller than Kwajalein—is Taka Bone Rate, in the Flores Sea south of Sulawesi. Taka Bone Rate (called Tijger in older texts) stretches 72 by 36 kilometers, covers 2,220 square kilometers, and includes 22 sandy islands. "Taka,"probably a Bugis word, is a generic term used throughout Indonesia for atoll or bank reef.

      The lagoon of an atoll, because it is so thoroughly cut off from the open ocean, forms a unique environment, and is often much richer in life than the lagoon side of, say, a small barrier reef. The level of organic matter in the water inside the atoll's lagoon is considerably higher than outside, allowing it to support as much as 10 times the biomass as the outer reef edge. And, because it is not adjacent to a large land mass, problems caused by run-off and turbidity are eliminated.

      The richness of the lagoon water is thought to be the result of deep ocean water percolating through the walls of the basement structure of the reef, bringing with it nutrients that previously had been locked away in geological storage.

      The Formation of Reefs

      Darwin's theory. British naturalist Charles Darwin first published his theory of coral reef formation in 1842, and it is still the dominant theory today. Darwin, in The Structure and Distribution of Coral Reefs, suggested that a fringing reef around the edges of an island would gradually grow outward, leaving a lagoon in its wake, and evolving into a barrier reef. If the island, over geological time, subsided, then what would be left would be an atoll:

      "Now, as the island sinks down, either a few feet at a time or quite insensibly, we may safely infer from what we know of the conditions favourable to the growth of coral, that the living masses bathed by the surf on the margin of the reef, will soon regain the surface...

      "Let the island continue sinking, and the coral-reef will continue growing up its own foundation, whilst the water gains inch by inch on the land, until the last and highest pinnacle is covered, and there remains a perfect atoll." (See diagram at right.)

      This, like natural selection, was pure speculation on Darwin's part. Atoll-formation was a phenomenon of history, and not something that he could "prove" with 19th century technologies. In fact, it was not until the 1951, when the U.S. Geologic Survey drilled Enewetak Atoll in the Marshalls to 1,340 meters, that Darwin's theory was confirmed: deep down, below the layer of coral in the atoll lagoons, the core samples revealed the volcanic rock of a former island.

      In the clear waters of Indonesian reefs, ultraviolet radiation can penetrate several meters underwater. Pigments made up of amino acids, called S-320, shield the delicate growing tips of shallow-water corals such as this Acropora sp.

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