Cyanide fishing
Encyclopedia
Cyanide fishing is a method of collecting live fish mainly for use in aquariums, which involves spraying a sodium cyanide
mixture into the desired fish's habitat in order to stun the fish. The practice hurts not only the target population, but also many other marine organisms, including coral
and thus coral reefs.
s and collectors, but it was soon used for catching food fish as well. It is illegal
in many of the countries in which it is practiced, although these laws are often minimally enforced. Grouper
, wrasse
, and coral trout
are among the more popular species of fish captured through cyanide fishing.
The World Resources Institute
determined that approximately 20% of the live fish traded on the Philippine market in 1996 were caught using cyanide; assuming this is reflective of southeast Asian practice as a whole, environmental engineer David Dzombak estimates that 12,000 to 14,000 tons of live food fish are caught each year using this method.
Colourful, particularly eccentric, and therefore rare coral fish are packed into plastic bags; up to two thirds of these fish die during transport. Estimates suggest 70 to 90% of aquarium fish
exported from the Philippines are caught with cyanide. Due to the post-capture handling stress and the effects of the cyanide, fish are bound to have a shorter life span than usual in aquariums. According to an interview with experienced aquarium owners, they were willing to pay more for net-caught fish because of the higher survival rate. They also said they would not trust an ecolabel
ling system, which can be misleading.
The basis for this illegal fishing method is, among others, the rising demand for live fish in the higher-class restaurants of the big cities, particularly in rich, nearby countries, which pay increasingly high prices. The extremely low wages of the fishermen in remote, underdeveloped areas, where there are no alternative sources of income, drive them to endure the health risks and possible prosecution.
commonly used to power jackhammer
s). When they reach the coral reef
s, they spray the poison between the individual layers, after which the yield is collected. Edible fish, of which a number are sold for general consumption, are first placed for ten to fourteen days in fresh water for "rinsing". Recent studies have shown that the combination of cyanide use and stress of post capture handling results in mortality
of up to 75% of the organisms within less than 48 hours of capture. With such high mortality numbers, a greater number of fish must be caught in order to supplement post catch death.
Cases have been reported of fishermen dumping drums of concentrated cyanide in places where fishing is difficult or economic times are hard. Such high concentrations normally kill most of the haul, but in these cases the objective is no longer to catch live fish, but to catch the largest amount period.
s. In humans, cyanides block the oxygen-transporting protein haemoglobin; the haemoglobin in fish is closely related to that of humans, and can combine with oxygen even faster. Through the irreversible combining of cyanide ions onto the active structural domain, oxygen is prevented from reaching the cells, and an effect similar to carbon monoxide
poisoning results. Coral polyps, young fish and spawn
are most vulnerable; adult fish can take somewhat higher doses. The use of cyanide is known to cause mortality on laboratory corals in measured doses, however these data are very difficult to quantify in regard to wild populations. In humans ingestion or breathing in of cyanide leads to unconsciousness within a minute; asphyxiation follows. Lower doses lead to temporary or permanent disability and/or sensory failure. This is a constant danger for the fishermen; there are many local accounts of such "occupational accidents", but such incidents are not recorded in official statistics or statements.
in zooxanthellae, which results in coral reefs losing colour; it also eliminates one of their major food sources. Even at very low doses, cyanide results in higher mortality levels among corals.
Most legal and illegal fishing methods cannot by themselves destroy a stable ecosystem. However, through the effects of synergy
, they have led to the breakdown of large coastal areas which were formerly robust fishing grounds.
Sodium cyanide
Sodium cyanide is an inorganic compound with the formula NaCN. This highly toxic colorless salt is used mainly in gold mining but has other niche applications...
mixture into the desired fish's habitat in order to stun the fish. The practice hurts not only the target population, but also many other marine organisms, including coral
Coral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
and thus coral reefs.
History and geography
Cyanide fishing is practiced mainly in saltwater fishing regions of Southeast Asia. Since the practice was never widely publicized or officially approved, its origins are uncertain, but it is believed to have originated in the 1950s in the Philippines. Later in the 20th century the practice was adopted by some fishing outfits in Indonesia, Thailand, Maldives, and Taiwan, among others. Cyanide fishing was initially developed to stun and capture fish for aquariumAquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
s and collectors, but it was soon used for catching food fish as well. It is illegal
Illegal, unreported and unregulated fishing
Illegal fishing takes place where vessels operate in violation of the laws of a fishery. This can apply to fisheries that are under the jurisdiction of a coastal state or to high seas fisheries regulated by regional organisations....
in many of the countries in which it is practiced, although these laws are often minimally enforced. Grouper
Grouper
Groupers are fish of any of a number of genera in the subfamily Epinephelinae of the family Serranidae, in the order Perciformes.Not all serranids are called groupers; the family also includes the sea basses. The common name grouper is usually given to fish in one of two large genera: Epinephelus...
, wrasse
Wrasse
The wrasses are a family, Labridae, of marine fish, many of which are brightly colored. The family is large and diverse, with over 600 species in 82 genera, which are divided into nine subgroups or tribes....
, and coral trout
Coral trout
The coral trout, leopard coral grouper, or leopard coral trout is a species of fish in the Serranidae family. Native to the western Pacific Ocean, its natural habitat includes open seas and coral reefs...
are among the more popular species of fish captured through cyanide fishing.
The World Resources Institute
World Resources Institute
The World Resources Institute is an environmental think tank founded in 1982 based in Washington, D.C. in the United States.WRI is an independent, non-partisan and nonprofit organization with a staff of more than 100 scientists, economists, policy experts, business analysts, statistical analysts,...
determined that approximately 20% of the live fish traded on the Philippine market in 1996 were caught using cyanide; assuming this is reflective of southeast Asian practice as a whole, environmental engineer David Dzombak estimates that 12,000 to 14,000 tons of live food fish are caught each year using this method.
Colourful, particularly eccentric, and therefore rare coral fish are packed into plastic bags; up to two thirds of these fish die during transport. Estimates suggest 70 to 90% of aquarium fish
Aquarium fish
In fishkeeping, species of aquarium fish vary with the water chemistry of the aquarium.For species of fish found in particular types of aquaria, see:*List of brackish aquarium fish species*List of freshwater aquarium amphibian species...
exported from the Philippines are caught with cyanide. Due to the post-capture handling stress and the effects of the cyanide, fish are bound to have a shorter life span than usual in aquariums. According to an interview with experienced aquarium owners, they were willing to pay more for net-caught fish because of the higher survival rate. They also said they would not trust an ecolabel
Ecolabel
Ecolabels and Green Stickers are labelling systems for food and consumer products. Ecolabels are often voluntary, but Green Stickers are mandated by law in North America for major appliances and automobiles. They are a form of sustainability measurement directed at consumers, intended to make it...
ling system, which can be misleading.
The basis for this illegal fishing method is, among others, the rising demand for live fish in the higher-class restaurants of the big cities, particularly in rich, nearby countries, which pay increasingly high prices. The extremely low wages of the fishermen in remote, underdeveloped areas, where there are no alternative sources of income, drive them to endure the health risks and possible prosecution.
Method
The fishermen dive into the sea usually without artificial breathing aids, although some use illegal and highly-dangerous apparatus (commonly garden hose surface-fed from the type of air compressorAir compressor
An air compressor is a device that converts power into kinetic energy by compressing and pressurizing air, which, on command, can be released in quick bursts...
commonly used to power jackhammer
Jackhammer
A jackhammer is a pneumatic tool that combines a hammer directly with a chisel that was invented by Charles Brady King. Hand-held jackhammers are typically powered by compressed air, but some use electric motors. Larger jackhammers, such as rig mounted hammers used on construction machinery, are...
s). When they reach the coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
s, they spray the poison between the individual layers, after which the yield is collected. Edible fish, of which a number are sold for general consumption, are first placed for ten to fourteen days in fresh water for "rinsing". Recent studies have shown that the combination of cyanide use and stress of post capture handling results in mortality
Fish mortality
Fish mortality is a term widely used in fisheries science that denotes the loss of fish from a stock through death. The term is also commonly used in British English as a synonym for fish kill. Fish mortality can be divided into two types:...
of up to 75% of the organisms within less than 48 hours of capture. With such high mortality numbers, a greater number of fish must be caught in order to supplement post catch death.
Cases have been reported of fishermen dumping drums of concentrated cyanide in places where fishing is difficult or economic times are hard. Such high concentrations normally kill most of the haul, but in these cases the objective is no longer to catch live fish, but to catch the largest amount period.
Mechanism
In seawater sodium cyanide breaks down into sodium and cyanide ionIon
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
s. In humans, cyanides block the oxygen-transporting protein haemoglobin; the haemoglobin in fish is closely related to that of humans, and can combine with oxygen even faster. Through the irreversible combining of cyanide ions onto the active structural domain, oxygen is prevented from reaching the cells, and an effect similar to carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
poisoning results. Coral polyps, young fish and spawn
Spawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
are most vulnerable; adult fish can take somewhat higher doses. The use of cyanide is known to cause mortality on laboratory corals in measured doses, however these data are very difficult to quantify in regard to wild populations. In humans ingestion or breathing in of cyanide leads to unconsciousness within a minute; asphyxiation follows. Lower doses lead to temporary or permanent disability and/or sensory failure. This is a constant danger for the fishermen; there are many local accounts of such "occupational accidents", but such incidents are not recorded in official statistics or statements.
Habitat Destruction
Many fishing and diving areas across the whole of South East Asia, already severely damaged from the impact of dynamite fishing, have been ruined or totally lost through cyanide fishing. Cyanide concentration slows photosynthesisPhotosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...
in zooxanthellae, which results in coral reefs losing colour; it also eliminates one of their major food sources. Even at very low doses, cyanide results in higher mortality levels among corals.
Most legal and illegal fishing methods cannot by themselves destroy a stable ecosystem. However, through the effects of synergy
Synergy
Synergy may be defined as two or more things functioning together to produce a result not independently obtainable.The term synergy comes from the Greek word from , , meaning "working together".-Definitions and usages:...
, they have led to the breakdown of large coastal areas which were formerly robust fishing grounds.
External links
nikswieweg.colibri-reisen.de: detailed article on illegal fishing methods in Palawan, Philippines- A Poisonous Business - Information on cyanide fishing that supplies the pet trade.