Cyanide fishing has severe negative impacts on coral reefs and fish populations in the Philippines. Cyanide binds to proteins in cellular respiration, inhibiting ATP production and causing marine life exposed to cyanide to die. This reduces food sources and tourism revenue, endangering the Philippine economy and food security. While cyanide fishing provides income, alternatives like anaesthetics are needed to preserve reefs and communities for the future.

1. Poisoning our reefs to extinction
INTRODUCTION:
Since 1962, fishermen all around the globe have been using cyanide to aid with the extraction of
tropical fish and coral in reefs located mainly in pacific orientated countries. However, despite being
an easy method it is also one of the most deadliest techniques of fishing used today, which causes
us to think of what exactly are the physiological and long-term effects cyanide fishing has on reefs
(specifically reefs located in the Philippines).
CYANIDE:
Cyanide is a singularly charged anion (group of molecules) that is
constituted of one nitrogen atom and one carbon atom that is joined with a
triple bond (Rathi, 2015). Although there are many different types of cyanide
the one used most commonly for fishing is sodium cyanide. When sodium
cyanide is released onto the reef (squirted by fishermen), the influx of
cyanide molecules are deadly to the aquatic invertebrates and fish.
CELLULAR RESPIRATION:
The cyanide is a deadly chemical as it interferes with cellular respiration
within the body. It directly relates to the final stage of cellular respiration
- the electron transport chain. Once the Kreb’s cycle has deposited energy in the form of reduced
coenzymes (NADH), these transfer energy through the electron transport chain (Jensen, 1984).
During the process of making ATP the electrons are attached to oxygen molecules as well as
hydrogen atoms which forms the water molecules by the last enzymefound in the Electron Transport
Chain, cytochrome c oxidase (Goodsell, 2000). The cytochrome c oxidase is composed of several
metal prosthetic sites including: two copper centres (CuA and CuB) as well as two metal irons
(Goodsell, 2000). The metal iron found within the protein is what the cyanide anion binds to thus
inhibiting the cytochromes function (Jensen, 1984). By inhibiting the cytochrome’s function this
means that the oxygen is no longer being bound to the electrons thus ATP cannot be formed
(Goodsell, 2000). As ATP is required for all living organisms to breath and create energy by impeding
on this critical process this means that signifies the fact that the marine organisms (corals,
invertebrates and fish) would no longer be able to live.
Although the marine organisms may be sensitive to cyanide, not all of the organisms die. Fish
exposed to a sublethal amount of cyanide (<50mL) exhibit a significant inhibition of several organs
(Alavandi, 2014). 14 days after exposure to the cyanide solution the fish display the maximum
inhibition of bodily functions with only: 30.87% of brain function,
26.58% of gill function and 21.97% of liver function (Alavandi,
2014). Because the brain utilises 20% of the body’s oxygen, it is
more susceptible to oxidative damage (Alavandi, 2014). With such
a decrease in the organs functions the fish’s mortality rate
diminishes and thus the population of fish decrease.
Much the same as the tropical fish, coral also suffers
dramatically when exposed to cyanide. Zooxanthellae is a
photosynthetic algae that lives in correlation with corals (Jones,
2012). Where coral provides protection, zooxanthellae provides
oxygen and nutrients such as glucose and amino acids for the
Figure 1: Cyanide molecule 3D
image that has a triple bond
between a carbon and nitrogen
atom

2. coral(Jones, 2012). More specifically zooxanthellae is also responsible for the flamboyant colours
that corals exhibit. When subjected to cyanide, zooxanthellae’s
cytochrome c is inhibited thus the photosynthetic process, in which
provides coral with its nutrients, is halted (Jones, 2012). After 48-72
hours after exposure to cyanide, the coral demonstrates a dull colour
or will begin to display a white colour, this is due to the decline in zooxanthellae (Jones, 2012). Loss
of zooxanthellae is a natural stress response to the sublethal amount cyanide. Such tests have been
conducted to assess the damage that cyanide fishing has on corals (Jones, 2012). It was concluded
that all corals exposed to doses above 2 M-min cyanid died; typically cyanide is squirted to capture
(Jones, 2012). The coral is also exposed to the cyanide solution (4.5 x 10-1
) thus resulting in a
significant loss of zooxanthellae (Jones, 2012). Loss of zooxanthellae can be as short as 1 min after
exposure. With such a loss of zooxanthellae coral mortality is considerably high, making it clearly
evident that cyanide has deadly consequences.
HOW CORAL AND FISH REDUCTION AFFECTS THE
ECOSYSTEM:
The corals and fish that are dying from the exposure to
cyanide is a major problem that needs to be addressed in the
present rather than in the future when it is too late. The decline in the
amount of live coral and dramatic loss of species and population of tropical fish
not only impacts the marine ecosystem but the human
population as well. Bottles used for cyanide fishing can be
up to a Litre in capacity, with typically a fisherman using 2
bottles a day; 2 Litres of exposure (per fishermen) is
estimated to be the equivalent of affecting 200m2
of coral
reef and fish that are in that vicinity. With a large number
of fishermen out on the reefs of the Philippines per day the
cyanide is exposed to a massive area of coral and fish.
The tourism industry in south east Asian countries mainly
rely on their exotic and fascinating coral reefs to attract
tourists from all around the globe (Conservation International, 2008). Specifically the Philippine
community relies on their vast variety of seafood as well as their flamboyant reefs to lure the large
travellers in. In the past 20 years the Philippine reefs have made the country $449 million
(Conservation International, 2008). However, with the reef degrading and no predicted
improvements this could prove to severely affect the tourism industry and thus the economy of the
Philippines.
Fishing is a major source of income for Filipinos, as estimated 1.61 million Filipino’s work as
fishermen (Llana, 2012). A decline in the population of tropical fish would mean that capturing live
fish and invertebrates would be more difficult. Without fish to sell this is a major problem for the
everyday man as his income is lost. It is highly important that these exotic marine organisms are
preserved and continued to reproduce as so many lives depend on it as a source of money to feed,
clothe and provide a home for many families in the Philippines (Llana, 2012).
Fish is a major food source of Filipino families; a decline in fish would jeopardise the families food
source thus could eventually lead to bigger problems such as an increase in food prices due to the
decline in the economy, however the loss of income by majority of families would cause a disastrous
effect as families would not be able to afford food prices (Llana, 2012).
Of course the problems associated with high mortality of marine organisms could produce
catastrophic consequences to the human population, another major problem is the consumption of
fish that have been affected with cyanide. Filipino people are estimated to consume at least 200
grams of seafood per day, however, with cyanide fishing methods being used by more fishermen in
the South-Eastern countries, this could prove to have tragic effects on the population (Llana, 2012).
Tropical fish that have not succumbed to death from the exposure of cyanide, although will still have
a mortality rate, will usually be consumed within days after capture (Llana, 2010). The cyanide
Figure 3: Relationship between cyanide dose and
zooxanthellae density 12 days after exposure.
Black symbols represent a significant difference to
the control variable. It is seen that the higher the
cyanide dosage is the zooxanthellae density
decrease thus the coral’s mortality rate increases.
Figure 2: Coral displaying a loss of
zooxanthellae around the edges (white
discolouration).

3. solution as squirted into areas on the reef is indigested by the fish and enters their digestive system
(how the cyanide binds to the cytochrome c). However, the cyanide remains in the digestive trace of
the fish and is absorbed by organs and tissues. When the fish is then consumed cyanide is
transferred from the fish to the human. Depending on how close the fish was to the release of the
cyanide and the amount of time exposed to it depends on the concentration found within the fish and
how affected the human will be by the cyanide. Within humans the cyanide binds to the haemoglobin
within the erythrocytes and thus the anion structure of the cyanide molecule binds with oxygen
quickly, thus inhibiting oxygen to reach cells (ICMC, 2010). By disallowing oxygen to the cells this
means synthesising ATP is reduced dramatically or restricted altogether, the reduction of energy
being produced causes such symptoms as intermitted unconsciousness to consciousness, followed
by weakness, headaches, vertigo, confusion and the perception of breathing difficulties (ICMC,
2010).
If the patients condition goes untreated the intermitted unconscious to consciousness will progress
to a deep coma, where breathing usually becomes shallow and rapid (ICMC, 2010). The insufficient
supply of oxygen means that the patient will breathe morerapidly to meetthe body’s oxygen demand,
the heart rate will also drastically increase to pump the oxygen in-taken by the body and supply it to
the tissues and organs (ICMC, 2010). The heart strain can also lead to pulmonary edemas which
then progresses to cardiac arrest then death (ICMC, 2010).
ALTERNATIVES FOR USING CYANIDE:
It is clearly evident that cyanide is a deadly chemical that has a huge impact on both marine
organisms and the human population. Although in an ideal world, capturing tropical fish should be
stopped this is not realistic as this is how majority of families in pacific-orientated countries earn their
income.
Although laws have been applied to ban the use of cyanide on the reefs, the Asian orientated
countries such as the Philippines do not reinforce these laws as only few people are caught each
year (Barber, 1997). To decrease the use of cyanide in such countries the laws have to be policed
by officials regularly. Although in present it will cost the country money to employ officials, this
however, will ensure that the reef will be protected and thus the Philippines will continue to earn
money from tourism in the future (Barber, 1997).
Another alternative to using cyanide, is to use a harmless yet effective chemical that will help the
fishermen capture fish whilst conserving the marine life. One way is to use fish anaesthetic. The
anaesthesia as used in various Asian countries is extracted from the plant Derris Tonkinesis (Brown,
2010). The anaesthesia agent is inhaled through the gills and enters through the blood stream
(Brown, 2010). From there it is pumped around the body and transported to the central nervous
system (Brown, 2010). Depending on the size of the fish and the dosage, anaesthesia can last from
12-48 hours (Brown, 2010). The components of the anaesthesia is not only harmless to the fishes’
organ functions but is also harmless to zooxanthellae and coral (Brown, 2010). Unlike cyanide, the
fish anaesthesia extracted from the Derris Tonkinesis plant does not leave a residue within the
tissues in the fish, hence, when consumed it will have no affect on the consumer (Brown, 2010).
Thus not only would the anaesthesia be more environmentally friendly and not toxic towards the fish
but it also proposes no danger to human consumers of the fish, and the fish will have a longer
lifespan as opposed to cyanide affected organisms (Brown, 2010). As well as these benefits,
fishermen would still be able to earn an income and the Philippines will still be able to make money
from tourism as this method would preserve the marine life.
CONCLUSION:
Cyanide proposes deadly consequences towards marine life and the human population. The
physiological affects include an increase in mortality rate of fish, corals, zooxanthellae and many
more organisms. Cyanide leaves residue in the tissue of the affected fish that have been captured
and if consumed (70% of captures are consumed) then this also proposes deadly consequences
towards the consumer, such as cyanide poisoning. Long-term affects of cyanide fishing includes an
obvious degradation of coral and the extinction of many species of fish, however, with this also
comes economical problems as the deterioration of reef and marine life poses a potential threat to

4. the tourism industry in the Philippines. The decline in species also is problematic for the fishermen
in the Philippines, because without fish not only will families become hungry, but there will be no
source of income leaving many families poor and forced to live in slums or on the street. The only
way to prevent these disastrous events from happening in the future is to change the methods used
and prevent fishermen from using cyanide on the reef. Officials should be employed to prevent
cyanide being used on the reef and other solutions could be used instead of cyanide that will help
the fishermen capture fish whilst also preserving the reef.
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