CARACAS, Venezuela — "Venezuela has declared a state of emergency in its western Lake Maracaibo to combat a fast-breeding aquatic plant that is clogging waterways and threatening fishing in one of South America's largest bodies of water, officials said Wednesday.
Authorities have ordered a massive clean-up of the floating green plant known as "dog weed" or "water lentil," which is covering as much as one-quarter of the lake, a shipping hub for the world's fifth largest oil exporting nation.
"It does not affect the fish because it is not a toxic plant; it's more a sign of the high levels of contamination in the lake," said Mariela Rincon, head of the local state commission for lake management.
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"The plant absorbs nutrients, and if you don't collect it, it dies, sinks to the bottom, and increases the contamination of the lake. We have a contingency plan, but really it grows so quickly," Rincon said. Officials said the aquatic menace began to appear around two months ago after heavy rains contributed to shifts in the lake's ecosystem that helped the plant flourish. The water vegetation has grown so rapidly authorities are removing around 1,500 cubic meters (52,970 cubic ft.) a day."
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http://www.enn.com/news/2004-06-10/s_24729.asp