LAKE MALAWI: GEOGRAPHY, GEOLOGY, IMPORTANCE, FAUNA, RIVERS - GEOGRAPHY - 2025

The Lake Malawi or Nyasa is a great lake in East Africa. It is the third largest of those located in the Rift Valley and the one furthest south. It is located between the countries of Malawi, Mozambique and Tanzania.

Among other aspects, it is known as the fourth largest freshwater lake in the world in terms of volume, also occupying the ninth place in the world in terms of area of ​​extension. It is also listed as the second deepest lake in Africa.

Lake Malawi, one of the most important in the Rift Valley System, Africa

NASA World Wind screenshot.

Within its waters there are approximately 700 species of cichlid fish, which are very abundant throughout the African continent. This makes Lake Malawi an important element for the economy of the nearby regions, especially for the fishing industry.

It is also one of the most prominent tourist places in the region, with various attractions, beaches and water sports activities such as kayaking or sailing.

In its surroundings there is a great diversity of flora and fauna. It is provided with fishing villages and vast totally uninhabited areas. The Nyasa is a meromictic lake, which means that its various layers of water do not mix with each other.

David Livingstone, a Scottish Christian explorer and missionary, was the first European to create a map of Lake Malawi. He was also the one who gave it the name "Lake Nyasa", although he used to call it "Lake of the Stars." Livingstone is also recognized for being one of the main promoters of Christianity in the country of Malawi.

Geological details

The entire Rift Valley is born from a geological fracture dating back 30 million years. It has a wide diversity of lakes among which is the Nyasa.

Lake Malawi is located within the Eastern Rift Valley system where the site's tectonic plate split in two. The lake is popularly estimated to be one to two million years old. The variations in the level of the lake's waters have varied over time within a range of 600 meters below the average level to 10 meters above.

The most similar chemical composition of the lake to the current one dates from some 60,000 years ago and comes from a chemical process after a period of extreme drought. It is established, within the geological history, the possibility that the lake has completely dried up millions of years ago. The estimated time range is from 1.6 million years to 0.57 million years.

Geographical data

The perimeter of the lake is made up of the coasts that link Malawi with the southern part of Tanzania and the eastern part of Mozambique. The length from north to south is 584 km and its width varies in a range from 16km to 80km. Its total area covers approximately 29,600Km2.

As for its surface, it is located at 472 meters above sea level. Its depth usually increases to 704 meters in the extreme north, where some wooded regions of Livingstone are located.

In the eastern part is the Nyika Plateau and in the west the Viphya Mountains, which plummet to the shores of the Malawian coast. In the southern part, in contrast, the waters are much shallower and even go below 40m in the central part and less than 200m at the far edges.

Characteristics of the water

The lake has alkaline water with a pH that ranges between 7.7 and 8.6. The temperature is warm and usually falls within 29ºC on the surface and 22ºC in the deeper areas. Oxygen levels reach their limit at a depth of 250 m, which allows many of the living beings that inhabit the waters to circulate in the shallower regions.

The water is usually quite clear allowing a vision could reach about 20 m although the most common is 3 m. In the rainy season, the waters can become somewhat cloudy due to the mud that comes from the rivers that converge with the lake.

Rivers that flow into the Nyasa

Lake Nyasa is fed by approximately 14 rivers, including two mainly: the Ruhuhu River, as one of the largest, and the Shire River.

The Ruhuhu River

It is located in the southern part of Tanzania in the eastern part of Africa. It is born in the Livingstone Mountains, also known as the Kinga Mountains, and its course reaches 160 km. It draws a path from the southeast to the southwest where it joins Lake Malawi.

The Shire River

It is the only mouth of Lake Nyasa. It is located on the southern coasts. It has a route of 402 km and is integrated into Lake Malombe.

Fauna

Fishes

Cichlids are the most abundant fish family in Lake Nyasa

Image by zoosnow from Pixabay

Lake Malawi is one of the most diverse sites in terms of the species of fish that inhabit its waters, especially due to the great variety of species of cichlids.

Cichlids are known to be part of the perciform order that refers to vertebrate fish. They have a wide capacity for adaptation and colonization that allow them to take advantage of both fresh and salty waters.

Currently, the number of cichlid species within Lake Malawi ranges from approximately 700 to 1,000. The range is usually quite wide due to the great abundance and variety of fish of this type, which makes it difficult to delimit figures. Other well-known fish include sardines and kampango catfish.

Invertebrates

The Nyasa is also home to some invertebrate beings. Among the mollusks, 28 species of freshwater snails and 9 types of bivalves stand out. As for the crustaceans, there are the Malawi blue crab (the only one that is not endemic to the lake), the shrimp of the atyidae family and the marine zooplankton with families such as cladocerans, copepods and ostracods.

Other animals

Other animals in the area include Nile crocodiles, hippos, baboons, Vervet monkeys, wild boars and a large number of African fish eagles.

Current risks of Lake Malawi

Certain factors, such as overfishing and pollution, have caused deterioration and risks in the Nyasa ecosystem. By 2010, 21% of freshwater fish were in danger of extinction, largely due to illegal fishing. This not only represents the danger for fauna, but for the various economic activities that sustain the local population.

Overfishing has affected fish popularly such as “chambo”, whose species Oreochromis karongae appears as one of the main sources of livelihood and which has presented a reduction of 70% to date.

Another factor of gravity has been reflected in the reduction of the water level, generated by accelerated population growth, deforestation and climate change. This led to a decrease in fish stocks and a significant reduction in the daily catch of local workers.

It should be noted that approximately 60% of the product that satisfies the nutritional needs in terms of protein within the country of Malawi comes from freshwater fish fishing.

Nearby mining activities also present a risk of water contamination. Among other aggressive dynamics are agriculture, the extraction of fresh water, the construction of dams and the integration of invasive species that are capable of altering the natural ecosystem of the place.

The fresh water of the planet, although it is found in a smaller proportion, contains 7% of the world's animal species and, in turn, protects a wide biodiversity. Due to this, the disappearance of at least one specimen is capable of generating a representative impact. Many of Africa's freshwater fish are not found in any other region on the planet.

Importance

The territory of Lake Malawi is distributed between three countries: Malawi, Mozambique and Tanzania. Part of the lake territory belonging to Mozambique has been declared a reserve since 2011. On the other hand, the part of the territory located within Malawi is part of the Lake Malawi National Park.

Today the lake is listed as a World Heritage Site, declared by UNESCO in 2011. Its geographical areas are also recognized for being the cradle of many hominid fossil remains.

The Nyasa has gained tourist relevance in recent years. Multiple accommodation sites and diversity of water activities are available. Boat trips, snorkeling and diving are several of the attractions that are often enjoyed. In addition, the southern part of the lake has a long coastline of beaches. Some of the most popular areas are the towns of Mangochi and Monkey Bay.

References

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