The Roatan Marine Park discourages DEET. See http://www.roatanmarinepark.com/tag/deet/. In 2009 they were challenged as to their claim it was harmful, so they posted the following question on Coarl-List, a professional, global, moderated forum of coral reef scientists:
"The Roatan Marine Park has always informed its visitors that they should not wear DEET and then enter the sea as it proves to be toxic and damaging for the reef and its inhabitants.
We are now being questioned and would like to provide people with scientific evidence to back our claims. Please provide us with links high lighting the detrimental effects that DEET had on corals, fish, crustaceans etc
Thank you"
There were just third responses to that question. The first said one could wash it off before entering the water. The second said:
"Am I the only one who finds it curious that a Marine Park imposed a ban on something without having a basis for that ban?? Is this DEET issue
anything like the lead weight issue? (You may recall that, about a year or 2 ago at least one marine park was considering a ban on uncoated lead
weights because of fear of lead dissolving in the ocean.) I fear that marine park rules with little or no scientific basis will
possibly lead to a public perception that all rules are frivolous."
The third response said (shortened here, it was very long and went WAY off topic!):
"Though I rather refrain from comments in issues like these, I feel that this case is illustrative of a bigger picture and hence worth commenting upon, i.e. it clearly shows the huge gap between coral reef scientists and the group of people that are "in the trenches" trying to protect the same systems that scientists study. While cooperation between the groups does exist (generally in the more well-off locations), many 2nd/3rd world locations simply have to figure out by themselves how to protect a reef facing heavy opposition from fishermen, developers, unsocial tourists, unwilling politicians etc.
While it would be nice to have scientific evidence for every management rule imposed, the overall variability among systems, sites, countries and regions, each with their own unique set of "problems", simply precludes this option. What now? A common sense approach (often with the added benefit that it is easier to convey to non-scientists) might be the next best thing. In this case, one could reason that DEET kills insects and as far as I know invertebrates are much more sensitive to poison than insects, so yes, probably not a good idea to throw the stuff on a reef. Does DEET reach corals etc in concentrations strong enough to kill them? Nobody knows, but the first line of reasoning is sufficient to apply the precautionary principle in this matter. Voila, done for now. While this DEET-case is just an example, the overall problem is obvious: Should one wait for scientific evidence that does not exist (yet) before implementing a rule that makes sense?"
The punchline seems obvious: DEET, on you, in the ocean, may not be good for the coral reef, but no one knows. They are just being careful, just in case.
More recently (2013), the Marine Pollution Bulletin published the following abstract:
"Coral, fish, plankton, and detritus samples were collected from coral reefs in Virgin Islands National Park (VIIS) and Virgin Islands Coral Reef National Monument (VICR) to assess existing contamination levels. Passive water sampling using polar organic chemical integrative samplers (POCIS) and semi-permeable membrane devices found a few emerging pollutants of concern (DEET and galaxolide) and polynuclear aromatic hydrocarbons. Very little persistent organic chemical contamination was detected in the tissue or detritus samples. Detected contaminants were at concentrations below those reported to be harmful to aquatic organisms." (my bold emphasis)
My conclusion: the RMP applied the precautionary principle, but implied it was a science-based argument. It was not. Since then, it appears the dilutions are so strong, that (at least in the Virgin Islands) DEET in the water is not an issue.
However, Roatan requires a lot of DEET, because of its mosquitoes and other critters....so there is a good chance the concentrations of DEET in Roatan waters are higher than in the Virgin Islands. High enough to be harmful? no one knows, so they are trying to be careful. But they are NOT making a claim based on science, just on concern.
"The Roatan Marine Park has always informed its visitors that they should not wear DEET and then enter the sea as it proves to be toxic and damaging for the reef and its inhabitants.
We are now being questioned and would like to provide people with scientific evidence to back our claims. Please provide us with links high lighting the detrimental effects that DEET had on corals, fish, crustaceans etc
Thank you"
There were just third responses to that question. The first said one could wash it off before entering the water. The second said:
"Am I the only one who finds it curious that a Marine Park imposed a ban on something without having a basis for that ban?? Is this DEET issue
anything like the lead weight issue? (You may recall that, about a year or 2 ago at least one marine park was considering a ban on uncoated lead
weights because of fear of lead dissolving in the ocean.) I fear that marine park rules with little or no scientific basis will
possibly lead to a public perception that all rules are frivolous."
The third response said (shortened here, it was very long and went WAY off topic!):
"Though I rather refrain from comments in issues like these, I feel that this case is illustrative of a bigger picture and hence worth commenting upon, i.e. it clearly shows the huge gap between coral reef scientists and the group of people that are "in the trenches" trying to protect the same systems that scientists study. While cooperation between the groups does exist (generally in the more well-off locations), many 2nd/3rd world locations simply have to figure out by themselves how to protect a reef facing heavy opposition from fishermen, developers, unsocial tourists, unwilling politicians etc.
While it would be nice to have scientific evidence for every management rule imposed, the overall variability among systems, sites, countries and regions, each with their own unique set of "problems", simply precludes this option. What now? A common sense approach (often with the added benefit that it is easier to convey to non-scientists) might be the next best thing. In this case, one could reason that DEET kills insects and as far as I know invertebrates are much more sensitive to poison than insects, so yes, probably not a good idea to throw the stuff on a reef. Does DEET reach corals etc in concentrations strong enough to kill them? Nobody knows, but the first line of reasoning is sufficient to apply the precautionary principle in this matter. Voila, done for now. While this DEET-case is just an example, the overall problem is obvious: Should one wait for scientific evidence that does not exist (yet) before implementing a rule that makes sense?"
The punchline seems obvious: DEET, on you, in the ocean, may not be good for the coral reef, but no one knows. They are just being careful, just in case.
More recently (2013), the Marine Pollution Bulletin published the following abstract:
"Coral, fish, plankton, and detritus samples were collected from coral reefs in Virgin Islands National Park (VIIS) and Virgin Islands Coral Reef National Monument (VICR) to assess existing contamination levels. Passive water sampling using polar organic chemical integrative samplers (POCIS) and semi-permeable membrane devices found a few emerging pollutants of concern (DEET and galaxolide) and polynuclear aromatic hydrocarbons. Very little persistent organic chemical contamination was detected in the tissue or detritus samples. Detected contaminants were at concentrations below those reported to be harmful to aquatic organisms." (my bold emphasis)
My conclusion: the RMP applied the precautionary principle, but implied it was a science-based argument. It was not. Since then, it appears the dilutions are so strong, that (at least in the Virgin Islands) DEET in the water is not an issue.
However, Roatan requires a lot of DEET, because of its mosquitoes and other critters....so there is a good chance the concentrations of DEET in Roatan waters are higher than in the Virgin Islands. High enough to be harmful? no one knows, so they are trying to be careful. But they are NOT making a claim based on science, just on concern.
