Proceedings of the International Cyanide Detection Testing Workshop

day. One cyanide tablet (2 g) is mixed with
approximately 3 liters of water in a plastic bag
or bottle. Based on this information, Fahrudin
(Fahrudin, 2003) calculated that the resulting
cyanide concentration is approximately 6.67
g/l.
Other studies suggest that cyanide
concentrations in squirt bottles vary by almost
an order of magnitude (Jones, Kildea et al.,
1999): 13 g/l (Pet, 1997), 100 g/l (Barber
and Pratt, 1997), 30±120 g/l (Johannes and
Riepen, 1995).
What Species Do Fishers Catch with Cyanide?
In the marine fi sh aquarium trade, species
targeted by cyanide fi shing include nearly all
coral fi sh species. However, the collectors
fi rst target the high price fi sh species, such as
emperor angelfi sh (Pomacanthus imperator), blue
surgeonfi sh (Paracanthurus sp.), and blue ring
angelfi sh (Pomacanthus annularis) (Fahrudin,
2003).
In the live food fi sh trade, common reef fi sh
caught are groupers (Serranidae), wrasses
(Labridae), and snappers (Lutjanidae). The
humphead (Napoleon) wrasse (Cheilinus
undulatus), high-finned grouper (Cromileptes
altivelis), and giant grouper (Epinephelus
lanceolatus) are traded only in small volumes
but are particularly valued (Johannes and
Riepen, 1995; Mak, Yanase et al., 2005)
Impact of Cyanide Fishing
It is hard to fi nd documentation on or to
estimate the impact of cyanide collection
on individual fi sh or on the environment
surrounding the fi sh. In addition, the aquarium
fi sh trade is highly dynamic and collection
techniques change quickly, depending on cost
of materials, ease of use, and individual ability
(Erdman and Pet, 1999). Below is a summary
of research results that estimate the impact
97
of cyanide fi shing on the fi sh collected as well
as the surrounding environment.
What Does Cyanide Do to the Fish?
As a general summary, hydrogen cyanide is
toxic to the majority of living matter (Eisler,
1991 citing Marrs and Ballantyne, 1987).
Specifi cally, cyanide appears to be acutely
toxic to aerobic organisms at concentrations
greater than 0.1 - 0.3 mg/l causing death
within 96 hours (Doudoroff, 1980 cited in
Mak, Yanase et al., 2005).
Eisler (Eisler, 1991) conducted an extensive
literature review to evaluate the effect of
cyanide on a large list of organisms including:
freshwater and marine aquatic organisms,
birds, and mammals. The results indicated
that fi sh were the most sensitive aquatic
organisms tested under controlled conditions.
Fish that were exposed to a range of 5.0 - 7.2
μg/l free cyanide per liter displayed signifi cant
adverse non-lethal effects, including reduced
swimming performance and inhibited
reproduction (Eisler, 1991). Mak et al. (Mak,
Yanase et al., 2005) report that a 10 μM
solution of cyanide is non-lethal to fi sh and
equivalent to what fi sh collectors use on the
reef.
There is also anecdotal evidence from fi sh
collectors and the marine aquarium industry
that fi sh caught without cyanide live longer
and have lower mortality rates throughout
shipment. Along with increased mortality
comes the need to catch more fi sh to respond
to the demand for aquarium fi sh. Ultimately,
the increased death caused by cyanide fi shing
increases the potential of overfi shing.
Metabolism of Cyanide in Fish
Hydrogen cyanide enters a fi sh’s bloodstream
through the gills and intestine and is rapidly
distributed to other body tissues. Cyanide is
toxic to fi sh because it interferes with oxygen