Proceedings of the International Cyanide Detection Testing Workshop

The first three of these destructive fishing
methods are discussed below. A detailed
assessment of cyanide fi shing (a frequently
used poison for fi shing), one of the most
commonly used destructive fi shing methods
used in Vietnam, is provided in section 3.
Destructive fi shing gear
The majority of fi shing gear used by fi shers
in Vietnam do not conform to mesh size
regulations (Nguyen Chu Hoi, 2008). For
example the sizes of trawl cod end, purse
seine’s bunt net and trammel net are so small
that a large proportion of juveniles are caught.
A number of harmful fi shing gear such as
estuary set nets and scoop nets are still used
(RIMF (2006). There is scant information on
the extent and impact of destructive fi shing
gear on fi sheries resources as well as impacts
on bycatch and habitats.
Dynamite/blast fi shing
Dynamite or ‘‘blast’’ fi shing is one of the
most immediate and destructive threats to
coral reefs worldwide. Dynamite fi shing
mainly occurs in the marine environment
in Vietnam. As with other methods of
destructive fi shing in Vietnam there is little
quantitative information available on the
extent of use of dynamite fi shing. A survey in
Nha Trang Bay showed that around 10% of
manta-tows showed evidence of blast fi shing
in the form of craters and or other obvious
physical damage to reef areas (Vo Si Tuan
et al., 2002, cited in Tuan V.S. et al 2005).
Based on the fi eldwork of the study team and
available data a Ministry of Fisheries (MOFI)
and World Bank report in 2005 concluded
that dynamite fi shing is still widespread in
some areas in Vietnam, but in areas where the
resource has already been severely depleted it
has ended (MOFI and WB, 2005). Dynamite
has also been recorded as being used in
conjunction with push nets where the push
net is used to herd the fi sh and dynamite is
120
thrown into the herded school of fi sh (Smith
et al., 2003).
Electro fi shing
Electro fi shing occurs in freshwater and salt
water areas in Vietnam. Several kinds of
electro fi shing are used in Vietnam a number
of which are detailed below.
Xiec Dien – electro fi shing equipment made
with a large Y-shaped wooden scoop net at
the end of which are two electric poles that
transmit the voltage into the water stunning
small shrimp and fi sh.
Gia nui – electric fi shing equipment is attached
to a dragnet to enhance its effi ciency
Gia tiep – fi shers use electric poles between
two boats and close to the sea fl oor affecting
a large area.
Incentives to engage in illegal electro fi shing
have been documented as a low initial
investment cost and compared to traditional
fi shing methods it is less labour intensive and
no specifi c knowledge is needed. This is in
contrast to traditional fi shing methods where
nets are more costly and require specifi c
fi shing knowledge of where and when to fi sh
(Strehlow, 2006). The level of enforcement
and the fi ne levels are also not considered a
suffi cient a deterrent. 2005 MOFI and World
Bank report concluded that the use of electric
fi shing in Vietnam is increasing, destructive
and diffi cult to prevent (MOFI and WB,
2005).
Cyanide fi shing
Poisons (Chat doc) are used widely in
Vietnam as a method of fi shing. One of the
most commonly used poisons is Cyanide.
Marine aquarium species that are diffi cult to
catch by mesh and scoop nets because they
hide in holes and burrows such as Angel fi sh
(Serranidae) and eels (Anguilla) are caught by
cyanide or anaesthetics (Truong Si Ky, 2006).