I believe several people have questioned whether the experiments done in the labor
atory by Cervino et al. mimic the actual cyanide plume dynamis that occur in the field. In my opinion they are similar to field conditions. James Cervino visited both Papua New Guinea and the Philippines and did some field experiments that are not part of the published paper (Figure 1 in the paper shows a cyanide plume created by a collector with a squirt bottle). He also interviewed collector who showed him corals that had been exposed to one squirt of cyanide. I have a number of these photographs where one can see white patches or white streaks across various species of Acropora. So, as Mike Kirda said there is no doubt that the cyanide is harmful to the coral in the field. I should note that I interviewed collectors in the Philippines in 1986 (The Effect of Sodium Cyanide on Marine Fish and Coral Reefs in the Philippines-Proceedings of the First Asian Fisheries Forum), who also told me the same things (cyanide kills the corals).
As far as plume dynamics are concerned, it is to be expected that the cyanide concentration will stay high near the center of the plume for at least 2-3 minutes in areas without strong currents. I know this from my own research with chemical plumes (my Ph.D. research studied responses by catfish to conspecific odours in an electronic monitoring tank at Texas A&M).
If you read the paper, you will see that James actually dosed corals with concentrations varying from 50 to 600 mg/liter (ppm) over various experiments. It is true to state that the adverse affects were not as pronounced at 50 ppm in comparison to 600 ppm. When the corals did not die in the short-term, Cervino documented a number of adverse affects including a) impairment of the rate of cell division (mitosis), b) expulsion of zooxanthellae (symbiotic algae needed for coral nutrition), c) inhibition of protein synthesis (shown with gel electrophoresis). The most severe situation was when corals shed their tunics (mantle tissue) leaving bare skeletons. The paper shows three genera of corals before and after. Actually, the research was conducted on 8 genera of corals and one sea anemone. In all cases, adverse affects were documented (although not every test animal died over the three month study period).
At the coral reef symposium in Bali, I discussed research on cyanide effects with corals conducted by Dr. Oakley in Malaysia (in the field). He put glass jars over the corals exposed to 1 ppm hydrogen cyanide (HCN). He told me that even at this low concentration the cyanide was harmfull to the corals. So far, I have not seen these results published (he may have done so, but I have not seen it).
My conclusion is that results may vary depending on the environmental conditions, initial exposure concentrations, exposure duration etc. But, in all cases the effects of exposing corals to cyanide are detrimental. Cyanide fishing needs to be stopped. NOW.
Peter Rubec