We all know that CN is a poison to both vertebrates and invertebrates including corals as it interferes with the cytochrome system. "(it is thought to exert its ultimate lethal effect of histotoxic anoxia by binding to
the active site of cytochrome oxidase thereby stopping aerobic cell metabolism)" see:
www.bordeninstitute.army.mil/cwbw/Ch10.pdf
But lets think beyond the rhetoric and examine the science and use a little common sense to see if we can figure out what the effects of CN use might have had on Phil coral reefs.
First the science. There are a couple of papers showing that CN kills corals and fish in the lab and in the field. OK -- that makes sense.
A lot of lab testing has been done and CN is sometimes detected in fish. OK that makes sense (although whether that testing is reproduceable and reliable is an open question. All testing has been stopped in the Philippines because of these questions.)
But what about real fishermen using CN under real collection conditions where the water currents are rapidly mixing and diluting the highly water soluble CN?
As far as I know, there is no paper that has looked at a coral reef as a whole -- say a kilometer reef front by 100 m wide where cyanide fishing is regularly practiced and then introduced CN fishing to a new reef where it has never been practiced and compared the results. To make a valid argument that CN is damaging coral reefs on a large scale in a country the size of the Philippines (7000 islands most with reefs) then I think it is fair to ask the scientist to be able to demonstrate the large scale impacts claimed. As far as I know, this has not been done.
Lots of divers go to the Philippines and claim to see lots of CN damage and dynamite fishing damage -- and most don't have a clue what they are looking at. As someone who started my career in coral taxonomy and discovered and named such important trade species such as Nemenzophyllia, I have spent a great deal of time staring at corals underwater. Differentiating between a coral that died from CN, dynamite, disease, Acanthaster, sediment, Drupella, storms etc etc. even a few weeks after it died is very very difficult. Most people have not had the luxury that I have had of living on a number of Philippine reefs and diving there every day for several years, watching the fishermen at work, the Acanthaster and Drupella eating corals, the storms and disease killing them.
In my personal experience, watching and working with CN fishermen in the center of CN use, Mactan and Olongo Islands, I have seen very minor damage from CN -- typically white fringes on coral around holes where they chased a fish. Remember, these fishermen are not trying to kill the fish so they are dosing as minimally as possible at a level to STUN not kill the fish.
A number of people have made their careers claiming that CN fishing has destroyed Philippines reefs -- and all I can say is -- show me the evidence from a good BACI sampling design on the scale of a real reef -- not a lab experiment or artificial appliation directly onto a coral.
Now lets use teh common sense approach. There are many reefs where CN fishing has been practiced by hundreds of fishermen for over 50 years now, and they do not appear to be any worse off than reefs where no CN fishing has been practiced.
I am just giving my personal experience/observations here, not trying to say that I have done the needed field experiments. So you can take my opinions and add a few dollars and buy a cup of coffee or ignore them.
To me, the problem with the CN issue is that it has diverted energy and resources away from solving the real problems which are how to come up with fiancial incentives to increase fish supply and reduce fishing pressure on wild caught fish. Hopefully, through our current work we can find a few answers.
Greg