I originally posted the following back in November of 2012 - it addresses the misinformation being posted in this thread. It had more to do with the seaweed aroma that accompanied the absolutely normal river run off. If the river water didnt flow into the sea, it would not be a river, it would be a lake. River water flows....
"Every now and then a combination of sea conditions bring on the cleansing of our Caribbean Sea of lots seaweed. This occurred once again last month when Hurricane Sandy passed over the island. Many pics of the seaweed have been posted on various trip reports here on our Negril Message Board. And as anyone who lives by the sea knows all too well, seaweed begins to create a rather vigorous aroma as it decays.
Along with these high seas, sea water was pushed up the South Negril River (near the roundabout downtown) and then came back out to sea along with the darkened colored river water that filters through the Great Morass. This is a normal occurrence and can spread along the coast of the West End or the main beach depending on the sea currents. This helps to restore the natural balance of the ecosystem of Negril.
This past week we have been questions from concerned visitors to Negril regarding this situation. It would seem that some individuals who may have been here at the time have taken these two events (the seaweed decaying on the beach and the river water darkening the sea) and concluded that "systems have broken down and the ocean water is foul..." which is a completely false assumption. As far back as November 1996 we have dealt with these unfounded rumors - this was prior to most travel sites and was on what was called the "Newsgroups" back in the early days of the Internet. Here is a link to the Negril Today page I wrote back in 1996:
http://www.realnegril.com/beingees/nn141196.htm
As mentioned, those who live by the sea know this is a natural event that happens from time to time, as these two further Negril Today pages clearly demonstrate - one from December 1997 thanking the late Jimmy Jackson for his help:
http://www.realnegril.com/beingees/nn221297.htm
As well as one from November 2001:
http://www.realnegril.com/beingees/nn091101.htm
We hope that this clears up the misinformation that people may be hearing about our tropical paradise of Negril."