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 of East Africa, where human history began. If you are eager to find out why Lake Nyasa has two official names and whether it really is home to the largest number of fish species in the world, continue reading.

Nyasa Lake
Nyasa Lake

About Lake Nyasa

Lake Nyasa is one of the lakes of the famous Great Lakes of Africa. You can read about the largest of them, Victoria and Tanganyika, in our other articles, but this article focuses on the southernmost lake, located in the natural Rift Valley of East Africa.

It’s commonly believed that Lake Nyasa in Africa was formed about 2 million years ago as a result of volcanic activity.It is fed by several tributaries: the Tanzanian Ruhuhu River, the Malawian South and North Rukuru Rivers, Dwangwa, Lilongwe, Bua, and the Songwe Rivers which border these two 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 is the ninth largest lake in the world.  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, Lake  Tanganyika, and comparable to such lakes as Lake Michigan and Lake Baikal. If we take a more perceivable size, the length of Lake Nyasa can be compared to the distance between London and Edinburgh, or New York and Pittsburgh, or St. Petersburg and the border of the Moscow Region; imagine that distance filled only with water!

The lake is shared by three countries: Tanzania, Malawi, and Mozambique. And the first two share it in the literal sense; Malawi owns most of the lake and believes that the border between the countries runs exactly along the shoreline. One the other hand, 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 and it is used by both nations.

Sunset at the Lake Nyasa
Sunset at the Lake Nyasa

If you hear about the African Lake Malawi, know that this is simply another name for Lake Nyasa. Just as the nation Malawi claims a great deal of the lake, they also refer to it as Lake Malawi. Moreover, both the lake and the state were renamed in 1964, prior to that, they both were called respectively Lake Nyasa and Nyasaland. Such interdependence of names is typical for the African toponymy; for example, mainland Tanzania was known as Tanganyika before independence, and this name lives on in Lake Tanganyika (read more about this amazing lake here).

One of the unique features of  Lake Nysa is that it is home to the largest number of fish species in the world, with many of them being endemic to the lake.

Fish of Lake Nyasa

Like other major lakes in East Africa, Lake 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 have 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 regularly (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 may 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 seek these 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 called Lake Malawi) is home to at least 600 known species of cichlids, and only about half of these have been studied. Other estimates suggest 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 adapt 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 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 or other small fish, so their food source is different.

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 that is how they get  their other name – peacock cichlid.

The most colorful and diverse cichlids are of the mbuna group. If you are an aquarist (or you know one) then you may know the importance of the “mbuna” fish for collectors.

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  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 terrific! Blue, yellow, gold, blue, and black colors in different combinations give a mosaic picture. Their coloring comes in the form of spots of different shapes and sizes, or oblong stripes through the whole body. Lake Nyasa is genuinely the grand natural aquarium of Africa!

Listed below are just a sample of the separate species found within these waters:

  • 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 is just a short list of the many  species of beautiful fish found by the hundreds in Lake Nyasa. In fact, even 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 classified 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 them from predators. Sometimes the mother opens its mouth after the babies have hatched to offer protection if the spawn are in danger, such is the power of the parental instinct. The fact that individual shoals protect their habitat is also interesting, they guard a spherical area and do  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; they prevent the competitors from entering their territory and seeking the female mbunas.

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 who are well-versed in this "fish geography" and know which species can be found in which part of the lake.

Other Fish of Lake Nyasa

It is the cichlids that make Lake Nyasa known, but other fish live in it, as well. One interesting specimen is the sharptooth catfish, whose bodies is elongated like an eel.

The Mastacembelus fish has an even longer body, which makes it at first glance appear to be a little like a snake. These fish can be up to one meter long.

A very unusual fish is the freshwater elephantfish( Mormyridae), which have elongated snouts resembling the trunk of an elephant, hence their   name. Using their snouts, these fish drill through the silt at the bottom of the lake to find food. They also have a superpower; with the help of their strong 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 away. Cool, right?

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

Other fish found in Lake Nyasa include:barbus (aka barbel), dotted synodontis and the redtail shark minnow, which is popular among aquarists. There are also many other non-cichlid species which are also species endemic to the waters of Lake Nyasa.

Other creatures around Lake Nyasa

You’re sure to see many other animals flourishing along the shores of Lake Nyasa. The abundance of fish in this water body attracts many African fish eagles who feast on the plentiful fish population. 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.

But, fish aren't the only thing the eagles eat. They also hunt other smaller birds, snakes, and even small turtles and crocodiles.

Among birds around the lake, there are cormorants and hamerkops, in addition to screech-eagles. Most of the animals live in the Lake Malawi National Park, inside of the country Malawi.

In terms of reptiles, there are many Nile crocodiles in lake Malawi. And if you’re hoping to spot larger mammals, you will probably encounter hippos, antelopes and baboons in the area. Hyraxes or dassies also live by the shores of the lake.

Nile crocodile
Nile crocodile

There are also lake flies, an insect that spends most of its life 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. Other insects from the area that are used as a human food source  are compressed midges (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 then simplly waved in the air as a swarm of flies passes threw; they get stuck to the oil in the pan and are ready to fry up into kungu.

Lake Nyasa Needs Help  

Unfortunately, the ecosystem of Lake Nyasa is affected by environmental and biodiversity issues.. 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 Lake 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 country of Malawi. Cultivation of land in the lake basin typically leads to soil erosion. As a consequence, various sediments fall into the waters of Lake Nyasa, preventing sunlight from penetrating through the water column. The lake's flora is becoming scarce, which means that 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: the 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: Tanzania, Malawi and Mozambique.

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 this body of water. There is a gradual increase in temperature in the regions adjacent to Lake Nyasa, likely do to climate change.

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 visitors can enjoy the wildlife, everything from mammals to birds. On the Malawian 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 land, which is home to animals like antelope, hippos and leopards.

On the Tanzanian side, approximately 50 kilometers to the north, is Tanzania’s famous ‘garden’: Kitulo National Park, also known as  the Garden of the Gods. Its main attraction is gloriuos 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 found within Kitolu National Park.

Kutilo National Park
Kutilo National Park

The abundance of plants in Kitulo attracts many beautiful butterflies and other insects. This, in turn, contributes to the number of lizards, chameleons, frogs, and various birds which reside in the park, too. Part of the park is composed of woodlands: Livingston and Ndumbi (in Ndumbi there is  a 100-meter-high waterfall to explore, as wel).

As for water activities on Lake Nyasai itself,  you can go snorkeling and diving. Since the colorful mbuna fish swim in the lake within a hundred meters from the shore, you do not even need to dive to great depths to see this vivid underwater world of the heart of Africa.

Other recreational lakeside activities are boating and fishing.

Another activity is swimming - and some swimmers make a real challenge of it!

For example, back in 2019, Martin Hobbs set a new record for swimming th entire length of this massive lake (570 kilometers!) in 54 days (by breaking his route into manageable legs). Every day Hobbs 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, judging by the number of records updated every now and then, Lake Nyasa sees swimmers from all around the world.

Revised on 18 July 2023
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