Cyanide fishing

Cyanide fishing

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.


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.[1] Later in the 20th century the practice was adopted by some fishing outfits in Indonesia, Thailand, Maldives, and Taiwan, among others.[1] Cyanide fishing was initially developed to stun and capture fish for aquariums 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.[1] 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.[1]

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.[2][3][4] 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.[5] They also said they would not trust an ecolabelling 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.


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 compressor commonly used to power jackhammers). When they reach the coral reefs, 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.[1] 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.


In seawater sodium cyanide breaks down into sodium and cyanide ions. 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.[6] 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 photosynthesis in zooxanthellae, which results in coral reefs losing colour; it also eliminates one of their major food sources.[1] 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.


  1. ^ a b c d e f Dzombak, David A; Ghosh, Rajat S; Wong-Chong, George M. Cyanide in Water and Soil. CRC Press, 2006, Chapter 11.2: "Use of Cyanide for Capturing Live Reef Fish".
  2. ^ Wabritz, C., Taylor, M., Green, E., Razak, T. (2003). "From Ocean to Aquarium". Unep-Wcmc: Cambridge. 
  3. ^ Barber, C.V., Pratt, R.V. (1998). "Poison and profits: cyanide fishing in the Indo-Pacific". Environment 40: 5–34. 
  4. ^ McManus, J. W., Reyes, R.B., and Nanola, C.L. (1997). "Effects of some destructive fishing practices on coral cover and potential rates of recovery". Environmental Management 21 (1): 69–78. doi:10.1007/s002679900006. PMID 8939786. 
  5. ^ "A glance at the marine aquarium fish trade in Hong Kong.". Tsang, A.. Retrieved May 27, 2005. 
  6. ^ Jones, R.J. (1997). "Zooxanthellae loss as a bioassay for assessing stress in corals". Marine Ecology Progress Series 149: 163–171. doi:10.3354/meps149163. 

External links

Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • cyanide fishing — use of sodium cyanide (or another cyanide compound) to stun and capture coral reef fishes for the aquarium and live food trade …   Dictionary of ichthyology

  • Cyanide (disambiguation) — Cyanide is a class of chemical compounds. Cyanide may also refer to: Cyanide and Happiness, a webcomic hosted on and written by four authors Cyanide poisoning, a form of poisoning that occurs when a living organism is exposed to a… …   Wikipedia

  • Cyanide — This article is about the class of chemical compounds. For other uses, see Cyanide (disambiguation). The cyanide ion, CN−. From the top: 1. Valence bond structure 2. Space filling model 3. Electrostatic potential surface 4. Carbon lone pair… …   Wikipedia

  • Fishing techniques — There is an intricate link between various fishing techniques and knowledge about the fish and their behavior including migration, foraging and habitat (Keegan 1986). All fish traps and methods of catching fish are based on this intimate… …   Wikipedia

  • Fishing reel — A spinning reel A fishing reel is a cylindrical device attached to a fishing rod used in winding the line .[1] Modern fishing reels usually have fittings which make it easier to retrieve the line and deploy ( cast ) it for better accuracy or… …   Wikipedia

  • Fishing lure — In line spinner lure with ring, dish, body/weight and hook Fishing lures are made in various creative designs like this top water lure …   Wikipedia

  • Sodium cyanide — Identifiers CAS number 143 33 9  Y Pu …   Wikipedia

  • Monofilament fishing line — A tangle of monofilament fishing line. The most common colorless variety can be seen. Monofilament fishing line (shortened to just monofilament) is fishing line made from a single fiber of plastic. Most fishing lines are now monofilament because… …   Wikipedia

  • Blast fishing — Dead fish and damaged coral as the result of blast fishing. Blast fishing or dynamite fishing is the practice of using explosives to stun or kill schools of fish for easy collection. This often illegal practice can be extremely destructive to the …   Wikipedia

  • Cormorant fishing — Chinese fisherman with one of his cormorants on Erhai Lake near Dali, Yunnan Cormorant fishing is a traditional fishing method in which fishermen use trained cormorants to fish in rivers. Historically, cormorant fishing has taken place in Japan… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”