lake victoria has experienced tragedic dwindling down of the native population of cichlids at a very rapid rate! Now it only possesses eight species.
Lake Victoria – the largest lake in Africa was discovered by British explorer John Speke in 1858.It is one of the largest lakes in the world covering 42,496 sq.Km. (26,560 sq.miles). As recently as 12500 years ago, the lake was believed to be only a grassy plain; this makes it the youngest of the three African rift lakes.
Lake Victoria or Nyanza as its called by local people is believed to be the most rapidly developing lake in regards to report growth of fish species numbers with over 350 district species developing since it came into existence.
Unfortunately, almost 50 years ago, the lake has experienced tragedic dwindling down of the native population of cichlids at a very rapid rate! Now it only possesses eight species.
There are several analysed theories our scientists have for the rapid depletion of the cichlids; these are being tabled almost in every workshop convened for the lake purpose but not put into effective implementation.
To call for all stake holders' attention once more, I will cover each briefly:
-The first of these reasons is one that for a number of years has been believed to be the sole reason (the most widely published); it is the introduction of two non endemic species of fish. The Nile perch (Lates niloticus) and the Nile tilapia (oreochromis niloticus), were introduced by British colonialists in1950's.
The Nile perch is quite a predatory species that is believed to be the majority of the reason for this decline. The Nile Tilapia on the other hand is a plankton eating fish which may not have had a greet affect on the native cichlid population but may also be competing for food with some of the species.
These fish were introduced to provide a food source for many countries, they grow much larger than the cichlids that exist in the lake: perch weighing 240 kg here been reported. Typical commercial sizes currently range between 3 – 6 kg and are being exported to United States, Japan, France, Germany, Belgium, Israel and Spain.
-The second invented reason is the vast amounts of pollution that is flowing into the Lake from the surrounding Countries. The Population boom in recent years vastly increasing the amount of pollution being pumped into the lake.
As the present time, oxygen levels at the bottom of the lake are not great enough to support life. Oxygen is not found 35 metres below the surface right down to the bottom – The Lake is 80 metres deep.
The pollution is a contributing factor to other problems in the lake!
- The increase of algae levels in the lake is another reason for the decline. With the pollution providing the necessary martinets for algae growth, the algae levels are five to ten times the levels of 1960's. This algae then dies off creating more pollution contaminating the lake further.
Currently there is no enough nitrogen in the lake to balance out the phosphorus coming in from the atmosphere, hence the lake has to use nitrogen – fixing algae to trap the nitrogen, but unfortunately it's the same algae that produce the toxins that kill fish.
As pollution levels go up algae growth go up in turn the algae that dies off creates more pollution in an apparent never ending cycle of lake destruction.
This is even having a great impact on the local populations around the lake – as you can see, it is a serious danger to the lake too! With these algae blooms is an increase in the dangerous blue–green algae causing more disease in the human population. Mostly those who drink the water directly.
Along with this growth in algae is the persistence of a water plant called hyacinth, much efforts have been put forward to restrain it but in vain. It is still found in many landing sites.
-Poor soil conservation and unfriendly environment land use in surrounding countries, rainwater flowing into the lake heavily eroded the mountains and hills, hence depositing into the lake thousands of tones of silt which overwhelmed it.
There are many research institutions all around the lake; their efforts have unearthed those theories, but because of lack of adequate funds they are helpless.The East African governments being the biggest beneficiaries should allocate good percentage of the taxes harvested from the lake for the lake cause!
Lake Victoria, once termed by British Statesman, Sir, Winston L.S. Churchill as peal of Africa is on the verge of becoming a dead lake! The situation is dire – let's stop milking the starving cow!
About the Author
freelance journalist, district political party secretary and african cultural advocate.