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Lake Nyasa, the Africa’s Grand Aquarium

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One of the world's most remarkable lakes is located in the Great Rift Valley region in East Africa where human history began and where tremendous changes in the landscape are continuing right now. If you are eager to find out why the lake has two official names, whether it really is home to the largest number of fish species in the world, and what desperate feat swimmer Martin Hobbs committed, read this article.

Nyasa Lake
Nyasa Lake

What Is Lake Nyasa

Nyasa is one of the lakes that make up the so-called Great Lakes of Africa. You can read about the largest of them, Victoria and Tanganyika, in our other articles, but here we will tell you about the southernmost of these water bodies located in the natural rifts of the Earth's crust in East Africa.

If we briefly outline the lake as a geographical object, it is worth saying that it was formed about 2 million years ago as a result of volcanic activity. It is fed by the Tanzanian Ruhuhu River, the Malawian South and North Rukuru, Dwangwa, Lilongwe, Bua, and the Songwe which is a border between these countries. Only one river, the Shire, flows out of the Nyasa. It comes from the southern end of the lake and runs through Malawi and Mozambique. The lake loses most of its water through evaporation.

Nyasa belongs to the top 9 of the world’s biggest lakes. Its The precise area of the Nyasa lake water surface is 29604 sq. km / 18395 sq. miles. Its maximal length ranges from 560 to 580 km / 340 to 360 miles. The width at the widest place is 75 km / 47 miles. The average depth of the lake is 292 m / 952 feet, and the maximal depth is 706 m / 2316 miles. is almost 30000 sq. km / 18641 miles. It is huge, especially if you look at it from above. The lake is at least 560 kilometers / 340 miles long. This is about 100 kilometers / 60 miles shorter than the longest freshwater lake in the world, the neighboring Tanganyika, and quite comparable to such lakes as Michigan and Lake Baikal. If we take a more perceivable size, the length of Lake Nyasa can be compared to the distance between Cologne and Munich, London and Edinburgh, New York and Pittsburgh, or St. Petersburg and the border of the Moscow Region. The lake is shared by three countries: Tanzania, Malawi, and Mozambique. And the first two share it in the literal sense - Malawi, which owns most of the lake, believes that the border between the countries runs exactly along the shoreline, but Tanzania is sure that the adjacent waters are also under its control. The disputes are mostly verbal among politicians, but in fact, Tanzania has access to a quarter of all the waters of Lake Nyasa.

Sunset at the Lake Nyasa
Sunset at the Lake Nyasa

If you hear a talk about Lake Malawi, you must know that we are still talking about Nyasa. The fact is that in the neighboring country of Tanzania and Mozambique, Malawi has the same name as the country itself. Moreover, both the lake and the state were renamed in 1964, and before that, they both were called respectively Nyasa and Nyasaland. Such interdependence of names is typical for the African toponymy; for example, the present mainland part of Tanzania being a separate territory before the independence and unification with Zanzibar was called Tanganyika, as well as the lake with the same name.

 One of the unique features of the lake is that it is home to the largest number of fish species in the world. And a major part of them lives only in this water body.

Fishes of Nyasa

Like other major lakes in East Africa, Nyasa is a natural treasure trove in terms of the diversity of fish species. Due to the manner of formation, these lakes have long since existed as closed systems which means that evolution there has taken place in isolation from all other aquatic systems. Thus, new species appeared that cannot be found elsewhere on the planet.

Today’s estimate is that the lake is home to over 1,000 species of fish. The study of fauna is relatively slow, although new species are discovered with regular frequency (in the scientific community, a new species is recorded about once a week). Another noteworthy fact: according to scientists, among the cichlids, a new species forms naturally every 20 generations. Thus, some scientists assume that the total number of fish species here can exceed 2000.

The most attractive species are, of course, cichlids. They are called "motley perches" for their bright and diverse coloration, and aquarists from all over the world hunt for beautiful fish to place in their home aquariums where they can be admired and studied.

Malawi Cichlids

According to recent estimates, Lake Nyasa (remember, it is also Lake Malawi) is home to at least 600 known species of cichlids, and only about half of these have been described. In total, the overall number of species is close to 800. When you see this figure, it's hard to imagine that all of them evolved from a single species that once made its way there from the neighboring Lake Tanganyika.

All local cichlids can be divided into three groups: tilapia, utaka and mbuna. The last group is of the greatest interest because of its uniqueness and attractiveness. Tilapias are quite common in other parts of the world as well: they have managed to be adapted in natural water bodies in Asia, North and Latin Americas, and even in cold Europe.

Utaka is a group of cichlid species whose name is loosely translated from local languages as “living in open water”. These fish are really considered pelagic, that is, living away from the shore in the water column or on the surface. In contrast, bottom dwellers sift through the bottom sand and thus find their food composed of microorganisms. But the utaka fish feed on plankton, as well as small fish, that is engaged in predation.

Utaka fish are rather dull-colored, especially females. They should not be too bright in color, as in open water they can themselves fall prey to larger predators. Although the male utaka can be quite colorful, and thus their other name – peacock cichlid, can be found in the special literature.

The most colorful and diverse by right are cichlids of the mbuna group. If are enthusiastic aquarists among your acquaintances, we can recommend you to conduct an experiment: say "mbuna" and watch the interlocutor smile, rolls his or her eyes dreamily and emotionally start talking about the extraordinary beauty and interesting habits of these speckled fish.

The word "mbuna" itself means something like "inhabitant of rocks, stones." These fish are so bright and eye-catching that they have to hide under stones near coastal rocks to stay safe. They feed mainly on algae formed on large rocks. A small part of their diet consists of animal food: small crustaceans and plankton.

The most beautiful and popular representatives of mbuna cichlids are pseudotropheus, melanochromis, and labidochromis. They all have names that are difficult to pronounce, but they look just terrific! Blue, yellow, gold, blue, and black colors in different combinations give a mosaic picture. The coloring features add variety: spots of different shapes and sizes, oblong stripes through the whole body, and various combinations of colors - Nyasa is genuinely a kaleidoscopic natural aquarium of Africa!

Listed below are the separate species worth of at least a fleeting glance at this wonder of  evolution: 

  • Hump-head (Cyrtocara moorii);
  • Venustus hap, or giraffe hap (Nimbochromis venustus);
  • Eureka red peacock (Aulonocara jacobfreibergi);
  • Nkhomo-benga peacock (Aulonocara baenschi);
  • Flavescent peacock (Aulonocara stuartgranti);
  • Red Zebra mbuna (Maylandia estherae);
  • Lemon yellow lab (Labidochromis caeruleus).

This list could go on for a long time, as the species of beautiful fish count by the hundreds. And in fact, many species moreover have color variations. Even the scientists do not immediately understand the classification of Malawian cichlids, so there is even a special group of fish into which poorly studied and not yet described species are temporarily added.

Lemon yellow lab (Labidochromis caeruleus)
Lemon yellow lab (Labidochromis caeruleus)

Cichlids from Lake Nyasa have remarkable features that help them survive in such a densely populated environment. Female cichlids hatch eggs right in their mouths to protect these from predators. Sometimes the mother opens its mouth even in case the spawn are in danger - such is the power of the parental instinct. The fact that individual shoals protect their habitat is also interesting. The areal is an imaginary sphere, and a particular group of fish does not allow other groups to penetrate it (most often, the mbuna fish are fenced off from the predatory representatives of the utaka group). The same applies to individual males during the breeding season, as they prevent the competitors from entering their territory.

Hump-head (Cyrtocara moorii)
Hump-head (Cyrtocara moorii)

We have already said that almost all species are considered endemic to Lake Nyasa; that is, they were formed in this body of water and live only here, not moving to other habitats. What is even more surprising is that individual species have secured certain small locations for themselves, such as bays. Only researchers are well-versed in this "fish geography" and know which species can be found in which part of the lake.

Other Fishes

It is the cichlids in the first place that make Lake Nyasa known, but other fishes live in it as well. Interesting to look at is the sharptooth catfish, whose bodies are elongated like those of eels. Mastacembelus fish has even longer bodies, which at first glance look like snakes. They can be up to one meter long.

Very unusual are the looks of the so-called freshwater elephantfish (aka Mormyridae), which have elongated snouts resembling the trunk of an elephant, which is reflected in the English name of this family (freshwater elephantfish). Using their snouts, these fish drill through the silt at the bottom of the lake to find food in it. They also have a superpower - with the help of their muscles they create their own weak electric field, which helps them navigate in the muddy bottom waters and find food, as well as to detect dangerous predators in good time.

A representative of the Mormyridae family
A representative of the Mormyridae family

In the waters of the southernmost of the Great African Lakes, barbus aka barbel,  dotted synodontis and the redtail shark minnow, which is popular among aquarists, also swim freely. There are also many other non-cichlid species. Among them, there are also many endemics of Lake Nyasa.

Animals by the Water and above the Water  

The abundance of fish in this water body attracts African fish eagles to its shores. These birds of prey fish out of the water on the fly; fish is this bird’s favorite delicacy. The African fish eagle can sit in the trees for long periods looking for shoals of larger fish and then dive and snatch their prey out of the water with their sharp claws. There are so many African fish eagles on Lake Nyasa that one of the neighboring countries, Malawi, has added the image of this bird on its coat of arms.

By the way, fish aren't the only thing the eagles are interested in as food. They also hunt other smaller birds, snakes, and even small turtles and crocodiles.

There are many Nile crocodiles on the shores of the lake. Of the larger mammals, one can also encounter hippos, antelopes, and baboons. Hyraxes or dassies, which on the outside resemble rodents but essentially are not, also live by the shores of the lake. Among birds, there are cormorants and hamerkops, in addition to screech-eagles. Most of the animals live in the Lake Malawi National Park, located in the coastal country of the same name.

Nile crocodile
Nile crocodile

There are other amazing creatures living by the lake that is also worth mentioning. These are the so-called lake flies that spend most of their lives in the form of larvae at the bottom of the lake in shallow water. The adult larvae rise to the surface, pupate, and take off in huge quantities, creating the effect of puffs of smoke over the water. If one is unaware of this feature of Lake Nyasa, this phenomenon can really be mistaken from a distance for strange smoke rising hundreds of meters above the water and obscuring the sky.

Both larvae and flies are an important part of the food chain in the lake's ecosystem. They pose no danger to humans. Moreover, locals catch these flies to make protein-rich meals from them. Compressed midges are the main ingredient in kunga cakes, or simply kungu. They are also used to make tortillas or burgers, or they can be used to dry cooked food to grate into a stew later. To simplify the process, a skillet is oiled and waved in the air with a swarm of flies to gather the main ingredient for making kungu.

Lake Nyasa Needs Help  

As it is the case for many parts of Africa, the ecosystem of Lake Nyasa is affected by environmental and biodiversity problems. For example, the fish for which this African lake is so famous are becoming fewer and fewer. This is indirectly and directly influenced by human activity.

Over the past 20 years, the number of people living on the Malawian shore of the lake has doubled. First of all, this means that fishing has also increased. The fact is that the same cichlids we so admire for their beauty are caught not only for sale as decorative aquarium species but also for consumption as food by local people. Second, there is increasing agricultural pressure on Nyasa's aquatic system, resulting in the depletion of natural resources.

The most densely populated lands are those on the southwest shore of the lake, in the territory of the poor state of Malawi. Cultivation of land in the lake basin leads to soil erosion. As a consequence, various sediments fall into the waters of Nyasa, preventing sunlight from penetrating through the water column. The lake's flora is becoming scarce, which means the herbivorous fish have less food and their population is dwindling, which can also lead to a decrease in the number of predators.

Many species of unique endemic fish are on the verge of extinction, such as the ntchila. The population of the much-loved chambo has also declined dramatically. Biologists are working with the authorities on programs to protect the region's biodiversity. Still, two factors are interfering: too high a rate of population and agricultural growth and a lack of coordination among the governments of the three countries that own the waters of Lake Nyasa.

There are also global threats to the region. The water level in the lake is dropping due to evaporation, which in turn negatively affects the climate of the entire area surrounding the body of water. There is a gradual increase in temperature in the regions adjacent to Lake Nyasa.

Things to Do on Lake Nyasa

In terms of tourism, Lake Nyasa is not as popular as its northern neighbors, Lake Victoria and Lake Tanganyika. Nevertheless, even here, nature and wildlife lovers will find something to do. In and around the lake there are many interesting fishes, birds, and large and small mammals to watch. On the Malawi side of the southern peninsula, there is a fairly large national park with the same name as the lake. It includes both an aquatic area and a large part of the land, which is home to, in addition to the animals already listed, leopards. There are other protected areas in different parts of the lake.

On the Tanzanian side, not far from the lake (less than 50 kilometers to the north) is the "most flowery" national park of the country, Kitulo, poetically called the Garden of the Gods. Its main attraction is luxuriant meadows, entirely covered with flowers, primarily orchids, as well as lobelia, lilies, asters, aloe, geraniums and others. In total, there are 350 species of plants.

Kutilo National Park
Kutilo National Park

This abundance of plants in Kitulo attracts many beautiful butterflies and other insects. This, in turn, contributes to the fecundity of lizards, chameleons, frogs, and various birds. Part of the park is composed of woodlands: Livingston and Ndumbi. In the latter, there is a 100-meter-high waterfall.

On the lake itself, you can go snorkeling and diving. Since the colorful mbuna fish swim in the lake within a hundred meters from the shore in great variety, you do not even need to dive to great depths to see the vivid underwater world of the heart of Africa.

Other recreational lakeside activities are boating and fishing. Both activities can be combined. And you can also just swim in the lake. Judging by the number of records updated every now and then by swimmers from different parts of the world, this activity is very popular.

The most impressive record was set in April 2019 by Martin Hobbs. He swam the entire length of Lake Nyasa, breaking his route into legs. It took Martin 54 days to cover the lake end to end (which, we should remind you, is about 570 kilometers long). Every day the desperate swimmer tried to swim about 11 kilometers, but it did not always work: sometimes bad weather interfered, and once Martin was caught by a tornado. Fear of crocodiles also got in his way, but luckily the crocodiles are only found on the coast, not everywhere around the lake.

We do not recommend you to repeat this reckless deed of Martin Hobbs. Still, we definitely recommend visiting the magnificent Lake Nyasa and seeing this unique natural site with its beautiful nature and so diverse animal world.

Revised on 11 July 2022
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