Cyanide fishing
Cyanidfischen is a non- selective fishing method in which mainly the chemical compound sodium cyanide (English: sodium cyanide) - one with cyanide closely related compound - is used. The chemical solution is spent by equipment in the immediate environment of the fish, after which they are unable to move and can be collected.
Cyanidfischen is banned in most countries of the world.
Occurrence
The method is used mainly in Southeast Asia, often referred to as silent alternative to dynamite fishing, which is also illegal in almost all countries of the world. Since 2000, it occurs increasingly in evidence, because enhanced administrative controls and seizures complicate the noisy and sensational dynamite fishing.
Cyanide fishing occurs mainly in the coastal zone (sea ) and is aimed at catching tropical fish that are used as a specialty or as ornamental fish. This method is also capable of capturing classic food fish, but is used less frequently. The use of cyanide is in standing waters (lakes ) less effective when turbidity obstructing the view. The substance must be introduced in very large quantities and then also endangers the diver, which is also dependent on good visibility when collecting the fish. In flowing waters, the motionless fish are indeed collected by downriver designed networks, the environmental damage is so massive that a once fished stretch of river in the foreseeable future can not be exploited again. In freshwater cyanide fishing can only be operated regionally and only for a very short time, is expensive and inefficient. Main occurrence are the broad coastal landscapes of the East Asian islands.
Scientists at the World Resources Institute (WRI ) estimate that the Cyanidfischer have deployed more than 1,000 tons of cyanide since the 1960s alone in the coral reefs of the Philippines. For the Indonesian archipelago, the toxic load is estimated as even greater. The toxic fumes often drive for days through the reefs and destroy everything they come into contact. They kill algae, aquatic plants, and contribute significantly to coral death.
Operation
Fishermen often dive without breathing assistance, but partly also with air compressor (DTG ) or thin breathing tubes in coral reefs and inject the venom between the individual sticks. Then the yield is collected. Food fish, of which respond to overdose before selling some who only come once for 10 to 14 days in fresh water to the " flushing ". Colorful, especially unusual and so rare coral fish are immediately packed in plastic bags, die either on the transport routes up to two thirds. Surely they are mainly designed for aquarists in the U.S., Europe and Asia. Even in the 1990s, 80 percent of coral fish of the western trade came solely from Palawan.
The reasons for this illegal fishing method is inter alia reflected in the increased demand for live fish in the better restaurants in big cities - increasingly financially stronger, neighboring countries - can be achieved for much higher prices. The extremely low wages of fishermen in less structured, remote areas that offer them no alternative sources of income, forcing them to take the health risks and possible convictions by law enforcement agencies in purchasing.
Many fishing areas and dive sites throughout Southeast Asia, previously damaged already strongly influenced by the dynamite fishing were characterized for years to come badly damaged, up to the total loss. Many of the slow-growing corals, especially the branched coral types, are an important protection area for young fish and fish fry and missing now. Most legal and illegal methods can not in itself destroy a stable ecosystem in general. However, there are synergistic effects, whereby the fishing is almost completely collapsed in large, coastal areas formerly excellent fishing grounds.
Chemical basis
In water and in sea water sodium dissociates into sodium and cyanide ions. The latter block in humans, the Fe ( III) ions of the enzyme cytochrome oxidase, which is no more oxygen can be transferred between the hemoglobin and the cells, the vital cell breathing is interrupted. Fish react only at somewhat higher doses the same way, coral polyps, juvenile fish and fish fry are more sensitive. In humans ( a direct threat to the fishermen ) unconsciousness when direct inhalation of hydrogen cyanide vapors escape the solution or accidental swallowing of sea water as it often occurs in divers after one minute. Then the " inner " done suffocation. Lower doses cause temporary or permanent paralysis and / or sensory deficits. There are many such " accidents " on the spot described, however, that appear in any statistics or official statements.
The effect is reversible in fish. The cyanide can separate a period of recovery from the metabolism of a stunned fish after, so that the animal recovers. The amount of absorbed cyanide ions is crucial. If it is too high, the fish died later because his organs have too many cell damage. At a low dose of fish can fully recover. The dosage may be from divers poorly controlled because the cyanide solution is distributed unpredictably by eddy in the water.