Cyanide fishing

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In respect of fishing techniques, cyanide fishing is a specific 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 incapacitate the fish. This practice affects not only the target population, it also has negative and damaging effects on many other marine organisms, including coral and coral reefs.

Contents

History and geography

Cyanide fishing is practiced mainly in saltwater fishing regions of Southeast Asia. Since the practice of cyanide fishing was never widely publicised or officially approved, its origins are uncertain; but it is believed to have originated in the 1950s in the Philippines. [1] Later in the twentieth century, the practice was adopted by some fishing operators 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 also used for catching fish for human consumption. 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 (WRI) 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 short tons (10,710 to 12,500 long tons ; 10,890 to 12,700 metric tons ) of live food fish are caught each year using this method. [1]

Colourful, particularly eccentric, and therefore rare coral reef 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.[ citation needed ]

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.[ citation needed ]

Method

The fishermen dive into the sea, usually without artificial breathing aids, although some use a 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 possible.[ citation needed ]

Mechanism

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.[ citation needed ] 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.[ citation needed ]

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.

Related Research Articles

<span class="mw-page-title-main">Cyanide</span> Any molecule with a cyano group (–C≡N)

In chemistry, a cyanide is a chemical compound that contains a C≡N functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom.

<span class="mw-page-title-main">Trawling</span> Method of catching fish

Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different species of fishes or sometimes targeted species. Trawls are often called towed gear or dragged gear.

<span class="mw-page-title-main">Coral bleaching</span> Phenomenon where coral expel algae tissue

Coral bleaching is the process when corals become white due to various stressors, such as changes in temperature, light, or nutrients. Bleaching occurs when coral polyps expel the zooxanthellae that live inside their tissue, causing the coral to turn white. The zooxanthellae are photosynthetic, and as the water temperature rises, they begin to produce reactive oxygen species. This is toxic to the coral, so the coral expels the zooxanthellae. Since the zooxanthellae produce the majority of coral colouration, the coral tissue becomes transparent, revealing the coral skeleton made of calcium carbonate. Most bleached corals appear bright white, but some are blue, yellow, or pink due to pigment proteins in the coral.

<span class="mw-page-title-main">Catch and release</span> Method of Fishing used for environmental or conservation reasons

Catch and release is a practice within recreational fishing where after capture, often a fast measurement and weighing of the fish is performed, followed by posed photography as proof of the catch, and then the fish are unhooked and returned live to the water. Using barbless hooks, it is often possible to release the fish without removing it from the water.

<span class="mw-page-title-main">Reef aquarium</span> Marine aquarium that displays live corals and other marine invertebrates as well as fish

A reef aquarium or reef tank is a marine aquarium that prominently displays live corals and other marine invertebrates as well as fish that play a role in maintaining the tropical coral reef environment. A reef aquarium requires appropriately intense lighting, turbulent water movement, and more stable water chemistry than fish-only marine aquaria, and careful consideration is given to which reef animals are appropriate and compatible with each other.

<span class="mw-page-title-main">Live fish trade</span>

The live fish trade can refer to the live food fish trade or to the ornamental fish trade. The fish can come from many places, but most comes from Southeast Asia.

<span class="mw-page-title-main">Southeast Asian coral reefs</span> Marine ecosystem

Southeast Asian coral reefs have the highest levels of biodiversity for the world's marine ecosystems. They serve many functions, such as forming the livelihood for subsistence fishermen and even function as jewelry and construction materials. Corals inhabit coastal waters off of every continent except Antarctica, with an abundance of reefs residing along Southeast Asian coastline in several countries including Indonesia, the Philippines, and Thailand. Coral reefs are developed by the carbonate-based skeletons of a variety of animals and algae. Slowly and overtime, the reefs build up to the surface in oceans. Coral reefs are found in shallow, warm salt water. The sunlight filters through clear water and allows microscopic organisms to live and reproduce. Coral reefs are actually composed of tiny, fragile animals known as coral polyps. Coral reefs are significantly important because of the biodiversity. Although the number of fish are decreasing, the remaining coral reefs contain more unique sea creatures. The variety of species living on a coral reef is greater than anywhere else in the world. An estimation of 70-90% of fish caught are dependent on coral reefs in Southeast Asia and reefs support over 25% of all known marine species. However, those sensitive coral reefs are facing detrimental effects on them due to variety of factors: overfishing, sedimentation and pollution, bleaching, and even tourist-related damage.

<span class="mw-page-title-main">Blast fishing</span> Using bombs underwater to kill fish

Blast fishing, fish bombing, dynamite fishing or grenade fishing is a destructive fishing practice using explosives to stun or kill schools of fish for easy collection. This often illegal practice is extremely destructive to the surrounding ecosystem, as the explosion often destroys the underlying habitat that supports the fish. The frequently improvised nature of the explosives used, and undetonated charges, means danger for fishermen and divers as well, with accidents and injuries.

<span class="mw-page-title-main">Fishkeeping</span> Practice of containing fish

Fishkeeping is a popular hobby, practiced by aquarists, concerned with keeping fish in a home aquarium or garden pond. There is also a piscicultural fishkeeping industry, serving as a branch of agriculture.

<span class="mw-page-title-main">Unsustainable fishing methods</span> Fishing methods with expected lowering of fish population

Unsustainable fishing methods refers to the utilization of the various fishing methods in order to capture or harvest fish at a rate which sees the declining of fish populations over time. These methods are observed to facilitate the destructive fishing practices that destroy ecosystems within the ocean, and more readily results in overfishing, the depletion of fish populations at a rate that cannot be sustained.

<i>Porites</i> Genus of corals

Porites is a genus of stony coral; they are small polyp stony (SPS) corals. They are characterised by a finger-like morphology. Members of this genus have widely spaced calices, a well-developed wall reticulum and are bilaterally symmetrical. Porites, particularly Porites lutea, often form microatolls. Corals of the genus Porites also often serve as hosts for Christmas tree worms.

<span class="mw-page-title-main">Environmental impact of fishing</span>

The environmental impact of fishing includes issues such as the availability of fish, overfishing, fisheries, and fisheries management; as well as the impact of industrial fishing on other elements of the environment, such as bycatch. These issues are part of marine conservation, and are addressed in fisheries science programs. According to a 2019 FAO report, global production of fish, crustaceans, molluscs and other aquatic animals has continued to grow and reached 172.6 million tonnes in 2017, with an increase of 4.1 percent compared with 2016. There is a growing gap between the supply of fish and demand, due in part to world population growth.

<span class="mw-page-title-main">Elkhorn coral</span> Species of coral

Elkhorn coral is an important reef-building coral in the Caribbean. The species has a complex structure with many branches which resemble that of elk antlers; hence, the common name. The branching structure creates habitat and shelter for many other reef species. Elkhorn coral is known to grow quickly with an average growth rate of 5 to 10 cm per year. They can reproduce both sexually and asexually, though asexual reproduction is much more common and occurs through a process called fragmentation.

<span class="mw-page-title-main">Fishing techniques</span> Methods for catching sea creatures, especially fish

Fishing techniques are methods for catching fish. The term may also be applied to methods for catching other aquatic animals such as molluscs and edible marine invertebrates.

Destructive fishing practices are practices that easily result in irreversible damage to aquatic habitats and ecosystems. Many fishing techniques can be destructive if used inappropriately, but some practices are particularly likely to result in irreversible damage. These practices are mostly, though not always, illegal. Where they are illegal, they are often inadequately enforced.

<span class="mw-page-title-main">Fishing industry in the Maldives</span>

The fishing industry in the Maldives is the island's second main industry. According to national tradition in the words of former President Maumoon Abdul Gayoom, "Fishing is the lifeblood of our nation, it is inborn. From the soil on which we live, to the sea around us, it remains an integral part of our existence. Fishing, and our country and its people, [are] one and shall remain inseparable forever." The Maldives has an abundance of aquatic life and species of fish. Common are tuna, groupers, dolphin fish, barracuda, rainbow runner, trevally and squirrelfish and many more. Aside from being of essential importance to the economy, fishing is also a popular recreational activity in the Maldives, not only among locals but by tourists. The islands have numerous fishing resorts which cater for these activities.

<span class="mw-page-title-main">Environmental issues with coral reefs</span> Factors which adversely affect tropical coral reefs

Human activities have significant impact on coral reefs. Coral reefs are dying around the world. Damaging activities include coral mining, pollution, overfishing, blast fishing, the digging of canals and access into islands and bays. Other threats include disease, destructive fishing practices and warming oceans. The ocean's role as a carbon dioxide sink, atmospheric changes, ultraviolet light, ocean acidification, viruses, impacts of dust storms carrying agents to far-flung reefs, pollutants, algal blooms are some of the factors that affect coral reefs. Evidently, coral reefs are threatened well beyond coastal areas. Climate change, such as global warming, causes a rise in ocean temperatures that lead to coral bleaching which can be fatal to the corals.

<span class="mw-page-title-main">Aquaculture of coral</span> Cultivation of coral for commercial purposes

Coral aquaculture, also known as coral farming or coral gardening, is the cultivation of corals for commercial purposes or coral reef restoration. Aquaculture is showing promise as a tool for restoring coral reefs, which are dying off around the world. The process protects young corals while they are most at risk of dying. Small corals are propagated in nurseries and then replanted on the reef.

The resilience of coral reefs is the biological ability of coral reefs to recover from natural and anthropogenic disturbances such as storms and bleaching episodes. Resilience refers to the ability of biological or social systems to overcome pressures and stresses by maintaining key functions through resisting or adapting to change. Reef resistance measures how well coral reefs tolerate changes in ocean chemistry, sea level, and sea surface temperature. Reef resistance and resilience are important factors in coral reef recovery from the effects of ocean acidification. Natural reef resilience can be used as a recovery model for coral reefs and an opportunity for management in marine protected areas (MPAs).

<span class="mw-page-title-main">Aquarium fishery</span>

Aquarium fishery is the process of fishing wild fish for sale to private and public aquariums.

References

  1. 1 2 3 4 5 6 Dzombak, David A.; Ghosh, Rajat S.; Wong-Chong, George M. (2006). "11.2: Use of Cyanide for Capturing Live Reef Fish". Cyanide in Water and Soil. CRC Press.
  2. ↑ Wabritz, C.; Taylor, M.; Green, E.; Razak, T. (2003). From Ocean to Aquarium. UNEP-WCMC Biodiversity Series. Vol. 17. World Conservation Monitoring Centre (WCMC). ISBN   92-807-2363-4.
  3. ↑ Barber, C.V.; Pratt, R.V. (1998). "Poison and profits: cyanide fishing in the Indo-Pacific" (PDF). Environment: Science and Policy for Sustainable Development. 40 (8): 5–34. doi:10.1080/00139159809604600.
  4. ↑ McManus, J. W.; Reyes, R.B. & 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. S2CID   22590485.
  5. ↑ Tsang, Anita C.W. (December 2001). "A glance at the marine aquarium fish trade in Hong Kong". www.HKU.hk. Porcupine!. pp. 9–12. Retrieved 27 May 2005.
  6. ↑ Jones, R.J. (1997). "Zooxanthellae loss as a bioassay for assessing stress in corals". Marine Ecology Progress Series. 149: 163–171. Bibcode:1997MEPS..149..163J. doi: 10.3354/meps149163 .
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