International trade in live fish and other marine species for international aquarium hobby market. Most fish, corals, and other marine aquarium species traded internationally are collected live from tropical and subtropical coral reefs, especially in the Philippines, Indonesia, and other Asian countries. Nearly half the world aquarium fish market is in the United States. Although the capture and marketing of live reef species provides a significant income source in remote communities, international trade has alarmed conservationists and environmentalists because of harmful collecting methods. A majority of live tropical fish are captured with sodium cyanide (NaCN), a highly toxic and inexpensive powdered poison. Divers use squirt bottles containing a cyanide solution or drop cyanide tablets into reef crevices where fish hide. The poison stuns the fish, making them easy to capture, and the fish usually recover after a few minutes. Fish are transferred to holding tanks on ships and then transported to international wholesalers. From 70–90% of fish captured with cyanide die later, however, due to damage to the liver, stomach, and other tissues. Another problem common in salt water aquaria is "sudden death syndrome," when fish inexplicably die soon after they are introduced to the aquarium. Some researchers attribute the syndrome to cyanide, which is stored in tissues during transport. Fish are often not fed during storage, but when they begin to eat in their new aquarium, or if they undergo even mild shock, the cyanide is released into the blood stream and kills the fish. Although solid figures are impossible to establish, estimates of the proportion of tropical live fish caught with cyanide are 75% or higher worldwide, and 90% in some countries.
The reefs where fish are captured fare as badly as the fish: one study found all cyanide-treated corals dead within three months after treatment. Coral reefs also suffer physical damage as divers break off chunks of coral to retrieve stunned fish. Despite harm to reefs and high fish mortality rates, cyanide is considered the most cost effective method to capture popular species such as angel fish and trigger fish.
Peter Rubec, a researcher with the International Marinelife Alliance, reports that an exporter operating from Manila initiated the export of marine fish from the Philippines in 1957. With almost 2,200 fish species, the Philippines has the highest reef fish diversity in the world, including 200 species that are commonly exported for the marine pet fish industry. In 1986 Filipino reefs provided as much as 80% of the world's tropical marine fish, a number that fell only to 70% by 1997. From 1970–1980 exports rose from 1,863,000 lb (845,000 kg) of live fish packed in water to 4.41 million lb (2 million kg) worth $2 billion dollars. Since then export numbers have fallen in the Philippines, as stocks have thinned and the trade has diversified to other countries, but in 1986 the country's marine tropical fish trade was worth $10 million dollars. Worldwide the value of aquarium fish was $100 million dollars, plus corals and other supplies.
Cyanide fishing was first introduced in the Philippines in about 1962. The technique has since spread to Indonesia, New Guinea, and other regions where live fish are caught. Cyanide has since been banned in the Philippines and Indonesia, but enforcement is difficult because fishing vessels are dispersed, often in hard-to-reach sections of remote islands. Despite legal bans, an estimated 375,000 lb (170,000 kg) of cyanide is still used each year in the Philippines. Cyanide fishing boats have even exploited established marine preserves and parks, such as Indonesia's Take Bone Atoll. Furthermore, as enforcement mechanisms develop, cyanide fishing can quickly spread to other countries, where laws are still weak or lacking.
The greatest problems of the live reef fish trade result from its mobility. The frontier of cyanide fishing has moved steadily through Southeast Asia to tropical Pacific islands and even across the Indian Ocean to the Seychelles and Tanzania, as fertile reefs have disappeared and as governments caught on to their fishing practices and began to impose laws restricting the use of cyanide and explosives. Since the market is international and lucrative, it does not matter where the fish are caught. Furthermore, fish exporters succeed best if they continually explore new, unexploited reefs where more unusual and exotic fish can be found. The migratory nature of the industry makes it easy for fishing vessels to move on as soon as a country begins to enact or enforce limits on their activities.
Starting in 1984 international conservation groups have worked to introduce net fishing as a less harmful fishing alternative that still allows divers to retain their income from live fish. To catch fish with nets, divers may use a stick to drive fish from their hiding places in the reef and then trap the fish with a fine mesh net. Reports indicate that long-term survival rates of net-caught fish may be as high as 90%, compared to as little as 10% among cyanide-caught fish. In Hawaii and Australia , where legal controls are more effective than in Southeast Asia, nets are used routinely. Although the aquarium industry has provided little aid in the effort to increase net-fishing, local communities in the Philippines and Indonesia, with the aid of international conservationist organizations, have worked to encourage net fishing. Increased local control of reef fisheries is also important in helping communities to control cyanide fishing in their nearby reefs. Local communities that have depended on reefs and their fish for generations understand that sustainable use is both possible and essential for their own survival, so they often have a greater incentive to prevent reef damage than either state governments or transient fishing enterprises. In an effort to help coastal villages help themselves, the government of the Philippines has recently granted villagers greater rights to patrol and control nearby fishing areas.
Another step toward the control of cyanide fishing is the development of cyanide detection techniques that allow wholesalers to determine whether fish are tainted with residual cyanide. Simply by sampling the water a fish is carried in, the test can detect if the fish is releasing cyanide from its tissues or metabolizing cyanide. Ideally this test could help control illegal and harmful fish trade, but thus far it is not widely used. Attempts have also begun to establish cyanide-free certification, but this has been slow to take effect because the market is dispersed and there are many different exporters.
Coastal villages also suffer from reef damage. Most coastal communities in coral reef regions have traditionally relied on the rich fishery supported by the reef as a principal protein and food source. As reefs suffer, fisheries deteriorate. Some researchers estimate that just 1,300 ft (400 m) of healthy reef the can support 800 people, while the same amount of damaged reef can support only a quarter that many people. Other ecological benefits also disappear as reefs deteriorate, since healthy coral reefs perform critical water clarification functions. Corals, along with sea anemones and other life forms they shelter, filter floating organic matter from the water column, cycling it into the food chain that supports fish, crustaceans, birds, and humans. By breaking ocean waves offshore, healthy and intact corals also control beach erosion and reduce storm surges, the unusually large waves and tides associated with storms and high winds.
Divers collecting the fish suffer as well. Exposure to cyanide and inadequate or unsafe breathing hoses are common problems. In addition divers must search deeper waters as more accessible fish are depleted. In 1993, 40 divers in a single small village were reported to have been injured and 10 killed by the bends, which results from rapid changes of pressure as divers rise from deep water.
Unfortunately there has been relatively little breeding of tropical fish in aquaria, at least in part because these fish often have specialized habitat needs and life style requirements that are difficult to produce under controlled or domestic conditions. In addition the aquarium trade is specialized and limited in volume, and gearing up to produce fish can be an expensive undertaking for which a reliable market must be assured. Equally unfortunate is the fact that American and European dealers in aquarium products tend to be elusive about the details of where their fish came from and how they were caught. If pet shops do not mention the source, many aquarium owners are able to ignore the implications of the fish trade they are participating in.
In addition to aquarium fishing, cyanide has now been introduced to the live food-fish market, especially in Asia, where live fish are an expensive delicacy. The live food/fish trade, centered in China and Hong Kong, is estimated to exceed $1 billion per year. The Hong Kong cyanide fleet alone has hundreds of vessels, each employing up to 25 divers to catch fish with cyanide for the Chinese and Hong Kong restaurant market.
Another harmful fishing technique is blast fishing—releasing a small bomb that breaks up coral masses in which fish hide. A single explosive might destroy corals in a circle from 10–33 ft (3–10 m) wide. The fish, briefly stunned by the blast, are easily retrieved from the rubble. Half the countries in the South Pacific have seen coral damage from blasting, including Guam, Indonesia, Malaysia, and Thailand. The technique has also spread to Africa, where it is used in Tanzania and other countries bordering the Indian Ocean.
Some environmentalists stress that simply eliminating the live fish trade is not an adequate solution. Because live fish are so lucrative, much more valuable than the same weight in dead fish, fishermen may be able to produce a better income with fewer fish when they catch live fish. Steering the fish capture methods to a safer alternative, especially the use of nets, could do more to save reef communities than eliminating the trade altogether.
[Mary Ann Cunningham ]
Rubec, P.I. "The Effects of Sodium Cyanide on Coral Reefs and Marine Fish in the Philippines". The First Asian Fisheries Forum. Manila, Philippines: Asian Fisheries Society, 1986.
Ariyoshi, R. "Halting a coral catastrophe." Nature Conservancy 47, no.1 (1997): 20–25.
Robinson, S. "A Proposal for the Marine Fish Industry: Converting Philippine Cyanide Users into Netsmen." Greenfields 15, no. 9 (1985): 39–45.