Proceedings of the International Cyanide Detection Testing Workshop

Introduction
Since the early 1960’s, coral reefs have been
increasingly exploited by fi shermen-who
use cyanide to capture reef fi shes alive, in
order to sell them to the live food fi sh trade
(sold to restaurants in Hong Kong and
mainland China) and marine aquarium fi sh
trade (Rubec 1986, Rubec 1987). Fishermen
stun the fi sh by squirting hydrogen cyanide
(HCN) solution onto coral heads and into
crevices in coral reefs. The sodium cyanide
(NaCN) tablets used by collectors in the
Philippines and Indonesia weigh about 20 g
each (Johannes and Riepen 1995). Fishermen
who collect ornamental fi sh for aquarium
tanks generally place one or two 20 gram
tablets of sodium cyanide (or potassium
cyanide) into a one-liter plastic squirt bottle
fi lled with seawater, while food-fi sh collectors
use three to fi ve tablets (Rubec et al. 2001).
The tablets sequentially dissolve in the squirt
bottle as collectors proceed to spray the reefs,
making it diffi cult to determine the cyanide
ion (CN- ) concentrations being applied.
It has been suggested that fi sh collectors
use concentrations ranging from 1,500 to
120,000 mg/L (Johannes and Riepen 1995;
Barber and Pratt 1997, 1998; Pet and Djohani
1998; Jones et al. 1999). Since not all of the
cyanide applied from squirt bottles dissolves,
it is sometimes visible underwater as a whitish
plume (Rubec et al. 2001). Not all fi shermen
limit themselves to squirt bottles. Reports
from the Philippines assert that 55-gallon
Methods for Detection of Cyanide and
its Metabolites in Marine Fish
Dr. Peter J. Rubec1 , Dr. Martin Frant2 , and Ms. Benita Manipula1 1. International Marinelife Alliance
2. Thermo-Fisher Inc. (formerly Thermo-Orion Inc.)
43
drums of cyanide have been dumped onto
reefs to kill and capture food fi sh (del Norte
et al. 1989, Johannes and Riepen 1995).
As far as cyanide testing is concerned, the
amount of cyanide that might be detected
is partly a function of the exposure
concentration of cyanide. If higher doses
are used in collecting, then higher initial
concentrations in the fi sh are possible. The
review conducted by SeaWeb at the CDT
Workshop quoted a paper by Fahrudin
(2003) that stated: “One cyanide tablet (2 g)
is mixed with approximately 3 liters of water
in a plastic bag or bottle” (SeaWeb 2008).
Based on this information, Fahrudin (2003)
calculated the resulting cyanide concentration
as approximately 6.67 mg/L (ppm). It should
be noted that the tablets weigh approximately
20 grams (not 2 grams) and that the tablets
are usually dissolved in a squirt bottle of
about one liter volume (Johannes and Riepen
1995). The minimum exposure concentration
squirted on a fi sh on the reef exceeds 1500
mg/L (Cervino et al. 2003).
At the Cyanide Detection Workshop (held
February 6-8, 2008 in Orlando, Florida) a
subgroup of experts (Dr. Brian Logue, Dr.
Robert Kobelski, Dr. Peter Rubec, Dr. Martin
Frant, Ms. Benita Manipula) met to discuss
the various methods that have potential
for measuring cyanide or other metabolic
byproducts in marine fi sh.