Message from Internet

Julian F. Sprung JSprung at
Wed Feb 11 10:00:58 EST 1998

Jennifer Langheld wrote:

Hello Everyone!

     I am doing a presentation on the destruction of coral reefs by cyanide
the Philippines and the Maldives Islands.  If anyone knows where I could
some information to get started, I would appreciate that very much.  Please
email me at: jlan7796 at with any information that you might

                             Thank you,

                             Jennifer Langheld

Dear Jennifer,

Are there reports of Cyanide fishing in the Maldives??? I had not heard
about it. The Philippines and Indonesia are the main regions where this
practice has spread. 

I am interested in the subject, not just because I think it is a serious
problem, which it certainly is, but also because there is an unproved
assumption in your inquiry, and in the anecdotal reports of others, that
cyanide kills corals. I have a hunch that it does not. However, its
widespread use as a fishing method would certainly be harmful to reefs
because of the massive fish mortalities cyanide fishing causes, and the
ease with which it is used to remove the big fish (and the demand for these
fish, live, at insane value to wealthy Asians). The problem is compounded
by dynamite fishing and other physically destructive methods employed in
the same regions.

I recall an article by Dr. Shinn in which he described how Acropora
cervicornis inserted into crude oil for extended periods of time was
unharmed (though oil with dispersants killed it). The corals were protected
by their mucus. I suspect that with cyanide sprayed on them the corals'
mucus would provide protection until tidal flushing washed away the poison,
which would happen quite rapidly. I have not personally tested this, so my
"observations" are from the armchair. However, I received an interesting
e-mail message-- posted to this list last June- that seems to confirm my
suspicions. I reproduce it for you here:

"As you may know, the Asian Development Bank, World Bank, GEF, AusAID, 
     JICA and the Government of Indonesia are formulating a major Coral 
     Reef Rehabilitation and Management Project in Indonesia and we seekthe
cooperation of Coral-List members in providing the technical 
     backstopping for this ambitious undertaking.

     One of the unresolved areas debated in Indonesia and the Philippines
is the extent to which coral reefs can recover from cyanide poisoning
associated with illegal fishing for the live fish trade.  In a 1986 paper,
Peter Rubec noted that researchers in the Philippines were divided on the
question of whether squirting sodium cyanide at coral reefs caused their
death.  "Scleratinian corals reacted by retracting their polyps and exuding
a mucoid substance.  In a matter of minutes, 
     the polyps came out again positioned in the usual way."  "A second 
     dose was given four months after the first. A day after the second 
     application, all corals appeared to have recovered.  But when the 
     stations were revisited three months later, all corals in the test 
     quadrats were dead."  The results may have been confounded by an 
     outbreak of COTS (Acanthaster sp.).  

     Can anyone explain a mechanism that would allow the corals to survive
for four months after the first dose, apparently recover after the second
dose, and then appear to have died 3 months later?  What have other field
or laboratory tests shown in relation to recovery rates following cyanide

     Peter King
     Asian Development Bank
     Manila, Philippines

From: Peter N. King <peking at>
To: coral-list at
Cc: riskmj at mcmail.CIS.McMaster.CA, sbettencourt at
Subject: Recovery from cyanide poisoning

Considering Mr. King's question, it should be obvious that the coral
mortality was from an unrelated causes (perhaps just Acanthaster, but also
possibly high water temp, or disease). It is easy to jump to conclusions,
i.e. cyanide is a poison, therefore it must kill corals. It may very well
do so, but without proper, controlled experiments, it is irresposible to
claim that it does. That it is harmful to reefs by virtue of fish removal
is something easier to demonstrate.

Perhaps you can find the reference info you are looking for by contacting
Mr. King. Good luck with your work and beware the temptation to claim you
know why corals die!


Julian Sprung

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