Lake Makgadikgadi in Africa

Secondary Birthplace of the Cichlid Population

Jan 2, 2009

Scientists have discovered a secondary hot spot for African cichlids with origins to a lake that no longer exists.

The Great Rift Lakes in Africa are considered the primary spot in the world for cichlid evolution. Over 30 thousand years ago, a mere handful of cichlids existed in the Rift Lakes and now there are several thousand species.

A new study revealed another source of cichlids in the Congo, Zambezi, Okavango and Limpopo Rivers that migrated from Lake Makgadikgadi, which no longer exists.

Evolution of Lake Makgadikgadi

Approximately three million years ago, the major rivers of the Kalahari Desert area drained into the Indian Ocean. One million years later, the movement of a fault line created a basin larger than Switzerland and the rivers began to flow into it. This was the birth of Lake Makgadikgadi.

The constant influx of water caused the lake to overflow and change its drainage pattern. As a result, the middle and lower Zambezi Rivers connected, thus forming Victoria Falls. With a new drainage path, the level of Lake Makgadikgadi decreased.

In the weather cycle, a dry period caused a severe decrease in flow of the rivers feeding the lake. The movement of another fault line caused a further reduction in water flow from the main feeder, the Okavango River. This was the final step in the elimination of Lake Makgadikgadi.

Evolution of the African River Cichlids

While still accessible, approximately 300 to 400 species of cichlids migrated from Lake Makgadikgadi into the surrounding rivers. Such species include:

A team of scientists who have been studying the cichlid population in African rivers discovered that the variety of river species were very similar to the cichlid species found in the Great Rift Lakes of Africa.

In an article by The National Geographic, Thomas D. Kocher, professor of zoology and genetics at the University of New Hampshire, stated “The high rates of speciation [evolution of new species] observed in these African cichlids are almost beyond belief, but the evidence is clear."

Compared to the cichlids in the Rift Lakes, only a few species are not found in the rivers. For example; algae scrapers and plankton eaters are only found in the lakes. It could be due to the fact that African rivers did not provide the conditions for these fish to thrive.

Why New African Cichlid Species Continue to Develop

Male African cichlids are known for their vivid colors and attract different species of females. This inter-breeding causes the constant evolution of new species, which is usually higher than other species of fish, such as South American Cichlids.

African cichlids are prolific breeders and the females take care of their young while the males move on to breed with other females.

African cichlids easily adapt to new surroundings by changing their feeding habits or by enduring a wider range of water quality. They are hardy fish and less susceptible to disease.

With these characteristics, it is understandable why the cichlids of Lake Makgadikgadi were able to make a new habitat in the surrounding rivers.

The copyright of the article Lake Makgadikgadi in Africa in Freshwater Fish is owned by Douglas DuHamel. Permission to republish Lake Makgadikgadi in Africa in print or online must be granted by the author in writing.