Wednesday, February 24, 2010

Fish Mortality - Lake Naivasha and the Mara River

An article just came out in the Daily Nation entitled, "Mystery of the lake's dying fish leaves experts in a whirl."

As you may remember, we have had similar events in the Mara River.

A few choice quotes from the article:

According to a research officer with Kenya Marine and Fisheries Research Institute, Mr George Morara, the initial investigations indicate very low levels of oxygen.


Most of the fish died at night or early in the morning, with very large sizes of fish, especially the spawning (females), being the most affected, according to the Aquatic Ecology expert.


The researcher said a lot of organic materials had been swept by raging storms into the lake, adding that the decomposition process demanded a lot of oxygen.  The researcher said that fertilizer runoffs from farms can make aquatic plants grow faster.


“When the increased numbers of aquatic plants eventually die, they decompose and support high amounts of bacteria which use large amounts of oxygen,” he adds.


Mr Morara estimated the dead fish to be between 700 and 1,000. He said further laboratory tests were being undertaken to determine the real cause of the deaths.

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