Lake Malawi (Nyasa) – History, Wildlife, Geography, Borders and More
Table of Contents
- 1 Lake Malawi (Nyasa) – History, Wildlife, Geography, Borders and More
- 1.1 Geography of Lake Malawi
- 1.2 Geological History of Lake Malawi
- 1.3 Characteristics of Lake Malawi Water
- 1.4 Colonization and European Discovery
- 1.5 Borders
- 1.6 Transportation
- 1.7 Wildlife
- 1.8 Mine Leak (2015)
- 1.9 Swimming on Lake Malawi
Lake Malawi (previously known as Lake Nyasa) is one of the African Great Lakes. It is located between Tanzania, Malawi, and Mozambique. It is the southernmost lake in the East African Rift (EAR) system. The lake is also called Lake Nyasa and Lago Niassa in Tanzania and Mozambique, respectively.
By volume, Lake Malawi is the 5th largest freshwater lake globally. By area, it is the 9th largest lake globally and ranks as the second deepest and the 3rd largest lake in the African continent. Globally, no other lake has as many fish species as Lake Nyasa, including not less than 700 cichlid breeds. The Mozambique government officially declared the Mozambique part of the lake a reserve on the 10th of June 2011. In Malawi, a section of Lake Malawi is part of the Lake Malawi National Park.
Lake Malawi is considered a non-mixing lake (meromictic) because the water layers don’t mix. Moderately small thermal and chemical ingredients maintain the unending stratification of the lake’s water as well as the oxic-anoxic borderline (relating to the water’s oxygen content).
Geography of Lake Malawi
Lake Malawi is between 350 miles (560 km) and 360 miles (580 km) long and approximately 47 miles (75 km) wide at the widest point. Lake Malawi’s total surface area is about 11,400 square miles (29,600 sq km). At its nethermost point, situated in a major depression in the north-central part, the lake is 2,136 ft (706 m) deep. A lesser depression located in the far north stretches to a depth of 1,732 feet (528 m). The lake is shallower on the southern half, less than 660 feet (200 m) in the far south, and less than 1,300 feet (400 m) in the south-central part. The lake has coastlines in eastern Malawi, southern Tanzania, and western Mozambique. The Ruhuhu river is the biggest river flowing into the lake, with a channel at the south edge – River Shire. River Shire is a tributary that flows into the larger Zambezi River located in Mozambique. Over 80 percent of the lake’s water loss is due to evaporation. This figure is considerably higher than the water flowing to River Shire. The water that flows into River Shire from Lake Malawi is important for the area’s economy because the water resources are useful for downstream biodiversity, hydropower, and irrigation. There have been concerns over the future effect of climate change on Lake Malawi because of the recent drop in water levels and the general drying trend. Changes are already being experienced in the climate of the lake area, with temperatures expected to increase across the country.
Lake Malawi is approximately 220 miles (350 km) southeast of Lake Tanganyika, which is also one of the great lakes of the East African Rift.
The Lake Malawi National park is situated at the lake’s southern end.
Geological History of Lake Malawi
Lake Malawi is an ancient lake and one of the prominent lakes of the Rift Valley. The lake is located in a gorge formed as a result of the opening up of the East African Rift, where the African plate splits into two. This phenomenon is known as a divergent plate tectonics boundary. The lake has usually been calculated to be one to two mya. However, recent evidence indicates that the lake is considerably older, with a basin that started forming about 8.6 million years ago. The deep-water condition first appeared 4.5 million years ago.
Over time, the water levels have seriously varied, ranging from nearly 2,000 feet (600 m) below the current level to 33-66 feet (10-20 m) above. There were periods when the lake almost completely dried out, leaving only a couple of relatively small, highly saline, and alkaline lakes in what presently are the deepest parts of Lake Malawi. Water chemistry that looks like the current one only appeared around 600,000 years ago. Significant periods of low-water are calculated to have occurred around 1.6 to 1-0.57 mya (where it might have completely dried out), 420,000 to 250,000-110,000 years ago, and 18,000 – 10,700 years ago. At the height of the low water period (1390 to 1860 AD), it may have been 390-490 feet (120-150 m) below the current levels.
Characteristics of Lake Malawi Water
The Lake Malawi’s water is warm and alkaline (7.7-8.6 pH). The usual surface temperature ranges between 75 to 840F (24 to 290C), while the deep sections are usually about 720F (220C). The thermal layer is located at a depth of 130-330 feet (40-100 m). The oxygen limit is at a depth of roughly 820 feet (250 m), thus limiting fish and other aerobic creatures to the uppermost section. For a lake, the water is really clear, and the clarity could be up to 66 feet (20 m). However, a little less than half of this figure is more prevalent, and it is less than 10 feet (3 m) in muddy inlets. The waters are muddier from January to March because of the inflow of dirty river water caused by the rain.
Colonization and European Discovery
Candido J. da Costa Cardoso, a Portuguese trader, was the first European recorded to have visited Lake Malawi having visited in 1846. In 1859, David Livingstone also visited Lake Malawi. He subsequently called it Lake Nyasa. He also had two nicknames for the lake: Lake of Storms and Lake of Stars. The Lake of Stars moniker came to being after Livingstone noticed lights from the lamps of the anglers in Malawi that resemble stars in the sky from a distance. Later, he called it the Lake of Storms after he experienced the erratic and intensely fierce gales that regularly swept through the area.
On August 16, 1914, Lake Malawi was the venue of a short naval onslaught when a British warship SS Gwendolen, captained by a certain Captain Rhoades, was informed that the First World War had started. He got instructions from the high command of the British Empire to “destroy, burn, or sink” the Hermann von Wissmann, the German Empire’s only warship on the lake, captained by a certain Captain Berndt. Rhoades’ crew located the German boat in a creek close to Sphinxhaven, the territorial waters of German East Africa. Gwendolen ruined the German ship with a solitary cannon fired from a distance of about 2,000 yards (1,800 m). In England, The Times hailed this short boat fight as the empire’s first naval triumph of the First World War.
The division of the surface area of Lake Malawi between Tanzania and Malawi is disputed. Malawi lays claim to the entire surface of the lake not located in Mozambique. Their claim includes the waters next to Tanzania’s shoreline. On the other hand, Tanzania claims that the international boundary runs through the middle of Lake Malawi. Both countries quote the 1890 Heligoland Treaty between Germany and Great Britain as proof. The dispute started when the British colonial administration, immediately after capturing Tanganyika from the Germans, put all of the lake’s waters under one jurisdiction (the Nyasaland territory), without a distinct administration for the Tanganyikan part of the lake. Two jurisdictions were later created in colonial times.
In 1967, the dispute reached a critical point when Tanzania formally made her displeasure known to Malawi; however, it wasn’t settled. There were occasional conflict flare-ups during the 1990s and the 21st century. Malawi’s oil exploration made the issue resurface in 2012, with Tanzania asking Malawi to stop exploration until the disagreement was resolved.
An accord between the Portuguese and the British was signed in 1954. The terms of the agreement made the center of Lake Malawi their border. The agreement did not include Likoma Island and Chizumulu Island, which the British kept and are now part of Malawi.
The SS Chauncy Maples began operating on Lake Malawi in 1901 as a floating church and clinic for the Universities’ Mission to Central Africa. Later, she served as a ferryboat and is presently being refurbished into a mobile clinic at Lusumbwe. It was expected that the renovation would be completed by the first six months of 2014. However, it was stopped in 2017. The MV Mpasa entered service in 1935. In 1951, the ferryboat MV Ilala entered service. The ferry has often been out of service in recent years. However, when operational, the ferry runs from the lake’s southern end in Monkey Bay to the town of Karonga on the northern end. Occasionally, she also runs to Tanzania’s Iringa Region. The ferry MV Mtendere started operating in 1980. By 1982, it was ferrying 100,000 commuters annually. However, she was out of service as of 2014. Mtendere usually serves the southern portion of the lake. However, operations were extended to Karonga if the Ilala was unavailable. The Marine Division of the Tanzania Railways operated the Tanzanian ferryboat MV Songea until 1997 when it became the Marine Services Company Limited. Built in 1988, Songea runs between Liuli and Nkhata through Mbamba Bay and Itungi every week. The worst disaster to occur on the lake involved the MV Vipya in 1946. The mishap resulted in the death of 145 people.
Creatures found in Lake Malawi and surrounding areas include monkeys, hippopotamus, Nile crocodiles, and a large number of African sea eagles that prey on the lake’s fish.
Lake Malawi Fish
For millennia, Lake Malawi has been a major source of food for inhabitants of its banks because the waters are full of fish. The four species of chambo are among the most popular. They include any of the four species belonging to the subgenus Nyasalapia (Oreochromis lidole, O. karongae, O. squamipinnis, and O. saka) and the closely related O. shiranus. Other breeds that support essential fisheries are the large kampango catfish (Bagrus meridonalis) and usipa (Engraulicypris sardella). Most fishing activities provide food for the growing human population living close to the lake, although some are shipped from Malawi. Water pollution and overfishing are increasingly threatening the fish population. Another threat is the decline in Lake Malawi’s water level, which is thought to be caused by deforestation, climate change, and water extraction by the growing human population. The kampango and chambo have been especially overfished (O. squamipinnis and O. karongae declined by around 94 percent, O. Idole might be extinct already, while the kampango declined by 90 percent between 2006 and 2016), and their continued existence is under threat. The International Union for Conservation of Nature recognizes 117 breeds of Malawi cichlids as threatened. Some of them have very small ranges and may be confined to rough shorelines only a few hundred meters long.
Lake Malawi Cichlids
Lake Malawi is known for being a location of evolutionary radiations amidst several animal groups, most notably the cichlid fish. Lake Malawi houses not less than 700 species of cichlid. However, some claim that the figure could be as high as a thousand species. The substantive number is uncertain due to undescribed species as well as the severe variation among certain species, making it very complex to delimit them. With the exception of four species (Coptodon rendalli, Astatotilapia calliptera, Serranochromis robustus, and Oreochromis shiranus ), all cichlids in Lake Malawi are endemic to the Malawi system, which includes the nearby Lake Malombe and the upper Shire River. Many of these species have become popular among aquarium owners because of their bright colors. Recreating a Lake Malawi biotope to house cichlids became popular among aquarium hobbyists. Most cichlids of the Nyasa lake are found in relatively shallow coastal waters. However, Diplotaxodon has been recorded down to depths of 660-720 feet (200-220 m), and many (especially Rhamphochromis, Copadichromis quadrimaculatus, and Diplotaxodon) are known from oceanic waters.
Lake Malawi’s cichlids are split into two major groups, and the overwhelming majority are haplochromines. The Astatotilapia sp. Ruaha (an undescribed species from the Great Ruaha River) is the sister species to the Nyasa haplochromines. They separated between 2.13 and 6.76 mya. The earliest variation within the Lake Malawi haplochromines happened between 1.20 and 4.06 million years ago. However, most of the radiations in this group are much younger; in severe cases, species may only have diverged only a few centuries ago. The haplochromines of Lake Malawi are oral incubators, but they differ extensively in ecology and general behavior. The Malawi haplochromines are divided into two – the mbuna and the haps. The mbuna is a name used popularly and locally. Mbuna translates to “rockfish” in Tonga. They are found at rocky outcrops; they are territorially hostile and often specialized aufwuchs feeders. The mbuna are often smaller, usually less than 5-inch (13 cm) long, and both sexes typically have bright colors. The males have egg-like yellow spots around their cloacal fin, although this feature is not unique to them. The second main haplochromine is the haps. Previously included in Haplochromis, they can be subdivided into three subgroups. The first is the comparatively large, often more than 8 in (20 cm) long, and hostile fish eaters that roam different habitats of prey, the open-water utaka (often close to rocks or sand) that feeds on zooplankton in schools. They are often of medium size. The final subtype is the aberrant species that are defined by the fact that they do not clearly fit into any of the other subdivisions. Mature male haps usually display bright colours, while male and female juveniles and mature females usually show a grey or silvery coloration with irregular black bars or other markings.
Non-Cichlids Fish in Lake Malawi
Although the overwhelming majority of fish species in Lake Malawi are cichlids, there are a few non-cichlid fish in the lake. They include the airbreathing catfish (Clarias and Bathyclarias and the kampango Bagrus meridonalis), the mottled eel (Anguilla nebulosa), the poeciliid Aplocheilichthys johnstoni), many cyprinids species (in genera Opsaridium, Labeo, and Barbus, Lake Malawi sardine (Engraulicypris sardella), mormyrids (Mormyrops, Petrocephalus, and Marcusenius), the African tetra, the spotted kill fish (Nothobranchius orthonotus), mochokid catfish, and the Mastacembelus spiny eel.
At the genus level, many of these are common in Africa. However, Bathyclarias is totally restricted to the lake.
Lake Malawi Invertebrates
Twenty-eight breeds of freshwater snails are found in Lake Malawi, 16 of which are endemic. It is also home to nine bivalves, 2 of which are endemic (the Nyassunio nyassaensis and Asphatharia subreniformis). The prevalent freshwater snails all belong to the genera Bulinus, Melanoides, Bellamya, Gabiella, and Lanistes).
Four snail breeds are found in Lake Malawi. The snails belong to the Bulinus genus (a known temporary host of schistosomiasis). A 1964 survey conducted in Lusumbwe found two endemic species of snails of the genus (B. succinoides and B. nyassanus) in the lake and two non-endemic species (B. forskalli and B. globosus) in lagoons separated from it. The former species are recognized temporary hosts of schistosomiasis, and larvae of the parasite were found in water containing these. However, in experiments conducted at the British Museum of Natural History, they could not infect the two species prevalent in the lake with the parasites. After the researchers spent many hours in and on the lake, they found neither B. forskalli nor B. globosus in the lake. In recent times, the disease has become a problem in Lake Malawi as the prevalent Bulinus nyassanus has become a temporary host. Initially noticed in the 1980s, this change is likely related to a reduction in cichlids that eat snails (for instance, Trematocranus placodon) caused by overfishing/and a new genetic variant of the schistosomiasis parasite.
Unlike Lake Tanganyika, which has many endemic shrimp and freshwater crabs, there are a few such species in Lake Malawi. The only crab found in the lake is the Malawi blue crab (Potamonautes lirrangensis), which is not quite common. The atyid shrimp is endemic to the lake. However, it is not well-known and has been mistaken for C. nilotica historically, a shrimp not present in the lake. Oceanic zooplanktonic include three copepods (Thermocyclops neglectus, Mesocyclops aequatorialis, and Tropodiaptomus cunnigtoni), two cladocerans (Bosmina longirostris and Diaphanosoma excisum), and many ostracods (including undescribed and described species).
Lake Malawi Flies
Lake Malawi is renowned for the huge hordes of small, benign lake flies, Chaoborus edulis. The swarms usually appear far out of the water and can be confused with smoke plumes. David Livingstone also noticed them when he visited. The marine larvae eat zooplankton. They spend the night in the upper water levels and the day at the bottom. They swim to the water surface and metamorphose into mature flies when they pupate. The adults have short life spans and the swarms, which are spiral-shaped and sometimes hundreds of meters tall, are a significant part of their mating activity. They lay eggs on the surface of the water, and the adults die. The larvae serve as an important source of food for fish. The adult flies are important to birds and the locals who use them to prepare kungu, a highly proteinous local delicacy.
Mine Leak (2015)
In January 2015, after a high-intensity rainstorm hit Northern Malawi, a sediment tank fell apart at the mine owned by Paladin Energy. Investigations revealed that fifty liters of non-radioactive material spilled into a nearby creek. In spite of reports of radioactive poisoning in the local media, scientific tests were carried out independently by the government on the local river and discovered that contrary to reports by some local media organizations, the leakage did not affect the environment.
Swimming on Lake Malawi
On five occasions, sixteen swimmers have completed the 25-kilometer individual swim across Lake Malawi from Cape Ngomba to Senga Bay.
2019: Jay Azran (South Africa) and Chris Stapley (Swaziland) 8 hours 40 mins, Ruth Azran (South African) 11 hours 8 mins, Andrew Stevens (Aus) 10 hours 50 mins
In 2019, a South African swimmer, Martin Hobbs, became the first to swim Lake Malawi’s full length (54 days). He also set the record for the lengthiest individual swim in a lake
2016: (current record) Robert Dunford (Kenya), Samantha Whelpton (South Africa), Michiel Le Roux (South Africa), Haydn Von Maltitz (South Africa), Greig Bannatyne (South Africa), Douglas Livingstone-Blevins (South Africa), Jean Craven (South Africa) 7hours 53 mins
2013: Kaitlin Harthoom (USA) 9 hours 17 mins and Milko van Gool (Netherlands) 8 hours 46 mins
2010: Abigael Brown (United Kingdom) 9 hours 45 mins
1992: Otto Thanning (South Africa) 10 hours 5 mins and Lewis Pugh(South Africa/United Kingdom) 9 hours 52 mins
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