Originally Posted by collyk
The larger fish also contain high levels of mercury.


Yikes! smile That statement might be a bit over the top but I know what you're trying to say...I wouldn't want people to think theyre going to be walking thermometers after eating a good sized fish. Not every large fish contains high levels of mercury and some large fish have very low levels of mercury. It would be more accurate to say larger fish are more likley to contain higher levels of mercury.

Ciguatera can be considered regional but in areas not considered to be "regionally affected" it may be present on one section of reef and not on others. It's a very perplexing critter...Here's a very good (but fairly technical) article written by two of the preeminent authorities on the subject...

http://www.ncf-net.org/library/CiguateraToxicon.pdf

and a study performed in Belize

http://www.sil.si.edu/digitalcollections/atollresearchbulletin/issues/00569.pdf

With respect to mercury...

http://www.greenfacts.org/en/mercury/l-2/mercury-2.htm

Note sections 2.3 & 2.4 specificaly

specific study on mercury in southern Belizean coastal waters

http://www.int-res.com/articles/esr2008/theme/Goliath/goliathpp7.pdf