Fish in Zambia
Although Zambia is a land locked Country, it has many rivers, natural lakes, man-made dams, waterfalls and wetlands – it is the most ‘water rich’ country in Southern Africa.
About 6% (45,000 square kms) of our surface area is water – with five natural lakes (Tanganyika, Mweru, Mweru-Wantipa, Bangweulu and Lukanga); three main rivers and their tributaries (Zambezi, Kafue and Luangwa); and, two large man-made dams (Kariba and Itezhi-tezhi). These waters are home to 409 different species and sub-species of freshwater fish.
Fish are the oldest aquatic vertebrates which first appeared nearly 500 million years ago. They make up the largest group of vertebrates, and like amphibians and reptiles, are cold-blooded. Fish do not have lungs to breathe, but instead have a special organ called gills, which draw in oxygen from the water and into their blood stream. They have a streamlined body which helps them quickly move through water, with almost all fish having fins and scales.
Fish have always been an important part of the protein diet for Zambians. Traditional fishing methods date back for thousands of years. Today it is an important part of the national economy, providing a relatively cheap protein and employing thousands of people – there are large commercial fish farms, small subsistence fishermen as well as sports anglers. The latter being a major part of our tourism industry. But, with more demand for fish as part of the national diet, more fish are being taken out of our rivers and lakes than their populations can support and the number of fish being imported into the Country every year is increasing.
Fish come in many shapes, sizes and colours. The largest freshwater fish in Zambia and Southern Africa is the Vundu (Heterobranchus longifilis). It is an air breathing catfish that can reach up to 1.5 m in length. Amongst the smallest are the cichlids which live in Lake Tanganyika – these can be less than 10 cm long. It is thought that 98% of the cichlids found in this lake are endemic. The Lake Tanganyika Sardine (Limnothrissa miodon) matures at just 6.8 cm and although they can grow up to 17 cm in length, they rarely reach longer than 10 cm long.
Zambia has at least 40 species of endemic freshwater fish
Amphilius cryptobullatus – Luongo River
Chiloglanis macropterus – Luongo River
Chiloglanis productus – Lunzua and Lufubu Rivers
Congoglanis safitta – tributaries of Lake Mweru, Luongo and Chambeshi Rivers, and Kasanka National Park
Synodontis ilebrebis – Lake Tanganyika
Synodontis lucipinnis – Lake Tanganyika
Zaireichthys kafuensis – the Gorge on the Kafue River
Benthochromis horii – Lake Tanganyika
Brown Julie (Julidochromis dickfeldi) – Lake Tanganyika
Chetia mola – Luongo and Luwombwa Rivers
Cyprichromis coloratus – Lake Tanganyika
Cyprichromis zonatus – Lake Tanganyika
Fire-tailed Pseudocrenilabrus (Pseudocrenilabrus pyrrhocaudalis) – Lake Mweru
Greenwoodochromis bellcrossi – Lake Tanganyika
Lamprologus laparogramma – Lake Tanganyika
Neolamprologus caudopunctatus – Lake Tanganyika
Neolamprologus prochilus – Lake Tanganyika
Neolamprologus cancellatus – Lake Tanganyika
Orthochromis kalungwishiensis – Kalungwishi River
Orthochromis luongoensis – Luongo River, a tributary of the Luapula River
Perissodus eccentricus – Lake Tanganyika
Petrochromis horii – Lake Tanganyika
Tilapia baloni – Luongo and Kalungwishi Rivers
Tilapia jallae – Upper Zambezi River system
Xenotilapia rotundiventralis – Lake Tanganyika
Kafue Killifish (Nothobranchius kafuensis) – Kafue National Park and upper Zambezi Rivers
Bangweulu or Rosenstock’s Killifish (Nothobranchius rosenstocki) – Lavushi Manda and Kasanka National Parks
Nothobranchius boklundi – seasonal pools on the Luangwa River
Nothobranchius milvertziv – Lushiba Marsh, part of Lake Mweru drainage
Nothobranchius oestergaardi – swamps of the Mwawe River and Lake Mweru Wantipa
Kneria paucisquamata – headwaters of the Luongo River
Barbus altidorsalis – Kafue eco-region
Barbus lornae – Chambezi River and Kasanka National Park
Barbus owenae – Lake Bangweulu, Chilui Islands and the Chambezi River
Coptostomabarbus bellcrossi – Luongo River, Lake Mweru and Kasanka National Park
Georgous Barb (Barbus bellcrossi) – Upper Zambezi River at Nyakesya
Petrocephalus frieli – Chambeshi River to Lake Bangweulu and the upper Luapula River
Petrocephalus longianalis – Luongo system of the lower Luapula tributary and the upper Luapula River
Banded Neolebias (Neolebias lozii) – restricted to the Kataba River
The ICUN Red List currently lists 16 fish species that occur in Zambia: two are critically endangered; three are endangered; six are vulnerable; and five are near-threatened.
Banded Neolebias (Neolebias lozii)
Kariba Tilapia (Oreochromis mortimeri)
Bigeye Lates (Lates mariae)
Greenhead Tilapia (Oreochromis macrochir)
Threespot Tilapia (Oreochromis andersonii)
Bangweulu or Rosenstock’s Killifish (Nothobranchius rosenstocki)
Forktail Lates (Lates microlepis)
Tanganyika Lates (Lates angustifrons)
Congo Blackfin (Altolamprologus calvus)
Mozambique Tilapia (Oreochromis mossambicus)
Tanganyika Clown (Eretmodus cyanostictus)
Fish and their Habitats
Zambia has 15 million hectares of water in the form of lakes, rivers and swamps.
These are divided into 3 main basins:
Zambezi Basin – comprising of the Luangwa River, Lukanga Swamps, Kafue River, upper Zambezi, Lake Kariba and lower Zambezi.
Luapula (Congo) Basin – consisting of the Chambeshi River, Bangweulu Lake and swamps, Luapula River and Lake Mweru.
Lake Tanganyika Basin – comprising of some of the most diverse aquatic ecosystems in the world.
The highest diversity of fish species is found in Lake Tanganyika, whilst Lake Mweru-Wantipa has the lowest diversity.
Lake Tanganyika is the second largest and the second deepest lake in the world – holding 16% of the world’s freshwater. It is the longest freshwater lake in the world being 660 km long and covers 32,900 square km. It is an ‘ancient’ lake and is thought to be about 9-12 million years old. The Democratic Republic of Congo (DRC), Burundi, Tanzania and Zambia all border the lake and its shoreline is home to about 1 million people.
The lake has over 250 known species of cichlid fish – 98% are endemic. They all belong to the subfamily pseudocrenilabrinae and many of these unique and diverse species live along the shorelines to a depth of about 100 m, although some do live in deeper waters where there is less oxygen. They are very varied in body shape, size and colouring and they also have fascinating complex behaviour patterns.
The largest cichlid in the lake is the Emperor Cichlid (Boulengerochromis microlepis) and males can grow up to 90 cm in length. They live along the shoreline in shallow waters and adults prey on other fish, as well as crabs, shrimps, molluscs, and insect larvae.
The smallest is the Dwarf cichlid (Nanochromis transvestitusus) which grow to just 3.4 cm in length. The second smallest is the Ocellated Shell-dweller (Lamprologus kungweensis) which grows to just 3.5 cm long.
Lake Tanganyika cichlids have become very popular with tropical fish enthusiasts. These colourful fish have interesting behaviours and displays and are relatively easy to breed in captivity, making them suitable for aquariums. Some of the most popular cichlids include: Tropheus, Frontosa, Goby, Sardine cichlids along with shell-dwellers, featherfins and sand-sifters.
The lake is also home to 80 other species of fish, with about 60% of these being endemic. In the open waters live the Tanganyika Sardine (Limnothrissa miodon) which can grow up to 17 cm in length. Although they are endemic to the lake, they were introduced into Lake Kariba in the late 1960s for the fishing industry. Every year between 20,000 and 30,000 tonnes are fished from Lake Kariba. Along with the Lake Tanganiyka Sprat (Stolothrissa tanganicae) these are both more commonly known as ‘kapenta’.
There are 11 sub-species of catfish belonging to the genus Synodontis. One of the more unusual is the Cuckoo catfish (Synodontis multipunctatus). These grown up to 27.5 cm in length and gather in large shoals in depths of about 40 m. Their breeding behaviour is similar to a cuckoo from which it gets its name – when cichlids lay their eggs, the Cuckoo catfish will quickly eat these eggs before they are collected by the cichlid and then will release and fertilise their own eggs. When the cichlid scoops up her own eggs into her mouth, she unwittingly collects the catfish’s eggs and when they are hatched they then eat the cichlids eggs. As these cichlids do not have any parental care it allows them to breed more frequently than some other fish.
Another species that has evolved in the lake are spiny eels (Mastecembelus) – with 13 out of the 15 species found being endemic. It is thought that these eels colonised and immediately diversified soon after the lake formed, which is why there is such a high diversity of species.
A deep water fish is the Lake Tanganiyka Perch (Lates angustifrons) which is also called the Buka fish. It is a species of ‘lates’ perch and is endemic to the lake. They can grow up to 200 cm and weigh up to 100 kgs, preying mainly on cichlids. They are now considered endangered due to over-fishing by commercial and sports fishermen.
Lake Mweru lies on the border of DRC and Zambia and is a rift valley lake. It is 131 km long with a maximum width of 56km and has an average depth of 8 metres, being shallower in the south. It has an elevation of 917m (higher than Lake Tanganyika which is 763m). It is fed by the Luapula and Kalungwish Rivers and their tributaries from the south and east. These both feed the lake through deltas and Vossai swamps which are themselves drained from the Bangweulu Swamps and floodplains. The Luvua River flows out of the lake in the north and joins the Lualaba to the west. It is the second largest lake in the Congo’s drainage basin. The western portion of the lake in the DRC has steep escarpments, rising to the Kundelungu Mountains beyond.
Due to rich plankton levels, Lake Mweru has 94 fish species. These are mainly different species of bream, catfish, tilapia, elephantfish and tiger fish. Around a third of these are endemic to the region, including five species of Barbus, three Nothobranchius, nine cichlids, three knerlids, five catfish and three mormyids. Also endemic are the Lake Mweru Sprat (Microthrissa moeruensis), Mweru Hump-backed Bream (Tylochromis mylodon), the Mweru Lampeye (Lacustricola moeruensis), the Fire-tailed Pseudocrenilabrus (Pseudocrenilabrus pyrrhocaudalis) and the Mweru Tilapia (Oreochromis mweruensis).
The lake has always been noted for its Greenhead Tilapia (Oreochromis macrochir), locally called ‘pale’ which are found in the quiet waters along the floodplains, feeding on microscpopic foods, such as algae. Females mouth brood the eggs and small fry in summer. These tilapia are now being threatened by an alien invasive fish species – the Nile Tilapia (Oreochromis niloticus) – which is displacing it in areas where both species occur, making the Greenhead Tilapia vulnerable.
The lake was also noted for its highly valued Rednose Mudsucker (Labeo altivelis). These fish graze on algae and migrate upstream from the lake into the Luapula River to the foot of Johnston Falls where they spawn between January and March. This massive spawning is intensively fished for ‘kapenta’ and caviar is produced from the eggs. The Rednose Mudsucker is also becoming rare in the Lake.
Lake Mweru Wantipa lies about 50 km to the west of Lake Mweru. It is considerably smaller, shallower and marshier than its neighbour. It is otherwise known as the Mweru Marshes. It is about 65 km long with a maximum width of 20 km and its average depth is only 2 m. The lake sits at an elevation of 933 m and the local watersheds drain into it. It seasonally floods therefore varying in side throughout the year – shrinking to less than a third during very dry seasons.
Since 1867 it has been known to dry out completely, and in 1949-50 thousands of fish, crocodiles and hippos died. This fluctuation in water levels means that there is an increase in the water’s salinity – which is why the fish species in the lake are limited. During periods of low water levels the waters recede into small pools, becoming deoxygenated. Only fish, such as the catfish (Clarias mossambicus), who can breathe oxygen from the air are able to survive. In seasons with heavier rains, the Kalungwishi River spills over and flows into the lake. The lake is part of Mweru Wantipa National Park.
It is thought that about 33 different fish species are found in the lake, mainly being species of carp, tilipia and catfish, such as the Greenheaded tilipia (Oreochromis macrochir), Threespot barb (Barbus trimaculatus), the ray-finned Microthrissa acutirostris and Chryschthys mabusi.
Lake Bangweulu – ‘where the water meets the sky’
Lake Bangweulu is part of one of the world’s greatest wetland regions, which also includes the Bangweulu Flats and swamps. The lake is about 75 km long and 40 km wide, expanding when the surrounding floodplains flood at the end of the rainy season. The combined area of the lake and wetlands reach around 15,000 square km. The lake has an average depth of 4 m and it is fed by 17 surrounding rivers, with the Chambeshi being the largest. It is then drained by the Luapula River.
The Bangweulu Lake, Flats and Floodplains are home of 87 different species of fish, mainly being catfish, tilipia and cichlids. There is one endemic species – the Bangweulu or Rosenstock’s Killifish (Nothobranchius rosenstockii) – which is found in the wetlands and in Kasanka National Park. These are colourful small, robust fish, 4 cm in length and are an ‘annual’ fish which live in shallow woodland pools. They have the unique ability to produce eggs that survive in dry pools where the adult no longer survive. These eggs then hatch during the next rainy season. They co-exist with other small species of annual killifish, catfish, barbus, Banded tilapia (Tilapia sparrmanii), Blackspot Climbing Perch (Ctenopharynx multispine) and Bulldog Fish (Marcusenius macrolepidotus).
Some of the other fish species that occur include Mormyids: Zambezi Parrotfish (Cyphomyrus discorhynchus), Bottle Fish (Mormyrus sp.) and Churchill (Petrocephalus catostoma). Barbus species include Sidespot Barb (Barbus neefi), Dwarf Barb (Barbus brevidorsalis), Copperstripe Barb (Barbus multillneatus) and Straightfin Barb (Barbus palundinosus). Characids include Dwarf Tigerfish (Brycinus peringueyi) and ‘Manda’ Tigerfish (Hydrocynus vittatus). Catfish include the ‘air-breathing’ Sharptooth Catfish (Clarias gariepinus), Blunt-tooth Catfish (Clarias ngamensis) and the very large Vundu (Heterbranchus longifilis). Cichlids include the Southern Mouthbrooder (Pseudocrenilabrus philander), Okavongo Tilapia (Tilapia ruweti) and the Redbreast Tilapia (Tilapia rendalli).
Zambia has two man-made lakes – Lake Kariba in the South which borders Zimbabwe, and Lake Itezi-tezhi to the West.
Lake Kariba is 223 km in length, 40 km wide and has an average depth of 29 m. It was filled between 1958 and 1963 after the completion of the Kariba Dam, by damming the Zambezi River which flows into the lake in the west, and out through the dam in the east. This large expanse of water houses 50 different species of fish, including five introduced species.
Of these five ‘exotic’ introduced species, two of them are thought to have entered the lake naturally – Redbreast Tilapia (Tilapia rendalli) and Yellow-belly Bream (Serranchromis robustus). Three ‘exotic’ species were established – Greenhead Tilipia (Oreochromis macrochir) in 1959; the small Lake Tanganyika Sardine (Limnothrissa miodon) introduced from Lake Tanganyika in 1967; and the Nile Tilapia (Oreochromis niloticus) which was not deliberately introduced but came from fish farms along the lake shore that drain directly into the lake.
Some species are thought to have disappeared or become rare – Neumann’s Suckermouth (Chilogalanis neumanii), Barred Minnow (Opsaridium zambezense) and the Spotted Sand Catlet (Zaireichthys rotundiceps). Their decline might have been caused by a change in their habitat with the building of the dam, or because of the rise of invasive predators, such as the Black Bass Micropterus species.
Lake Kariba has two types of fisheries – subsistence fishermen who mainly fish the native species like Green Happy Cichlid (Senanochromis codrington) and Eastern Bottle-nosed Mormyrid (Mormyrus longirostris); and commercial fisheries who fish for the species that are locally known as ‘kapenta’.
Fish species that are popular with sports fishermen are the Tiger Fish (Hydrocynus vittatus), Kariba Tilapia (Oreochromis mortimeri), African Electric Catfish (Malapterurus electricus), Vundu (Heterobranchus longifilis), Red Breasted Tilapia (Tilapia rendally), Distichodus schenga, Nkupe (Distichodus mossambicus) and Purple Mudsucker (Labeo congoro).
It was feared that the African Mottled Eel (Anguilla bengalensis) would disappear from the lake as their young come up from the sea and would not be able to get over the dam wall. But they are thought to still be in the lake in low numbers.
Lake Itezhi-Tezhi mainly lies in Kafue National Park and is a man-made reservoir that was filled by the Kafue River after the construction of the Itezhi-Tezhi dam in 1977. The dam was built to control the flow of water for the Kafue Upper Gorge power station more than 260 km downstream. It covers 390 square kms and has an average depth of 15 m, with the deepest depth being 55 m. Seasonally water levels can fluctuate by around 10 m.
Common fish species found in the lake, and in the Kafue River, include Green Headed (Oreochromis machrochir) and Threespot Tilipia (Oreochromis andersoni), Red Breasted Bream (Tilapia rendalli), Speckleface Bream (Serrachromis angusticeps), Purple Largemouth (Serrachromis marcocephalus), Bulldog Fish (Marcusenius macrolepidotus), Striped-tailed Robber (Brycinus lateralis), Smooth Spine Spot Barb (Barbus poechi), Bottlenose (Mormyrus lacerda) and Silver Barbel (Schilbe mystus).
In the 1980s only 24 different fish species were found in the lake, with Kariba Bream (Oreochromis mortimeri) being the dominant species. It was thought that the species of cyprinids, elephantfish and catfish had been unable to adapt to the new lake environment conditions due to fluctuating water levels which had adversely effected their feeding and spawning grounds.
Although other fish species were found to have naturally come from the Kafue and Musa Rivers, such as Bottlenose and Ray-finned fish, there was found to be a decline in the diversity of species as they had not been able to adapt to the new lake conditions. As the lake had low diversity with low densities, and as it was rich in zooplankton, it was decided to introduce an alien species to increase human food supplies and local employment. In 1992, 3,950 Lake Tanganyika Sardine (Limnothrissa miodon) from the Mpulungu waters of Lake Tanganyika were introduced.
Even though 90% of the lake is within the National Park, the building of the dam did alter the diversity of the local fish species, especially with the introduction of alien fish for commercial fishing. The Sharp-toothed Catfish (Clarias gariepinus) which is locally known as the ‘Black Barbel’ because of its colouring, can be found gathering in large numbers below the dam wall as the water is released, leaping and swimming strongly against the currents endeavouring to move upstream.
Zambia has three main rivers – Zambezi, Kafue and Luangwa Rivers which are all part of the Zambezi Basin. There are numerous smaller rivers to the north which form the Luapula (Congo) Basin which include the Chambeshi and Luapula Rivers.
Africa’s fourth largest river, the Zambezi, rises in the Mwinilunga District in the north-west. It flows through Angola for about 230 kms before entering back into Zambia at the Cholwezi rapids. It then passes through the flat Barotse floodplains, turning east to form the border between Zambia and Namibia where it is joined by the Chobe River and Caprivi Swamps of Botswana. Then, for about 500 km, it borders Zimbabwe, flowing over Mosi-oa-Tunya Falls (Victoria Falls) and into the Batoka George and into Lake Kariba. From the Kariba Dam it is joined by the Kafue River, flowing through Lower Zambezi National Park, narrowing again before the confluence with the Luangwa River and then into Mozambique.
Several fish species are mostly limited to the Zambezi River region, such as Dwarf Sanjika (Opsaridium zambezense), Brown Squeaker (Synodontis zambezensis) and Zambezi River Bream (Pharyngochromis acuticeps). Larger species, such as Vundu (Heterobranchus longifilis), Electric Catfish (Malapterurus shirensis), Nkupe (Distichodus mossambicus) and Chessa (Distichodus schenga) are only found below the Falls. Other species found in the Lower Zambezi River include Cornish Jack (Mormyrops anguilloïde), Eastern Bottlenose (Eastern Bottlenose), Large Scale Yellowfish (Barbus marequensis), Mozambiqie Tilapia (Oreochromis mossambicus), Tigerfish (Hydrocynus vittatus), Zambezi Happy (Pharyngochromis acuticeps) and Zambezi Parrot Fish (Hippoptamyrus discorhynchus).
The Zambezi’s two main tributaries within Zambia are the Kafue and Luangwa Rivers.
The Kafue River is the Country’s longest river – flowing 1,604 kms from its source in North Western Province draining the Lukanga Swamps and through the Copperbelt before flowing through Kafue National Park and into Lake Itezhi-Tezhi. From the Itezhi-Tezhi dam it then spreads out through the Kafue Flats, becoming up to 50 kms in width, to form the shallow floodplains of Blue Lagoon and Lochinvar National Parks. It then drops down the Kafue Gorge and Dam, entering the Zambezi just before Chirudu.
The Kafue river has about 60 different species of fish. These include 18 species of Barb, 13 bream, six catfish, four largemouth, three minnow, two catlet, two mudsuckers, and three Robber. It is also home to Bottlenose (Mormyrus lacera), Bulldog (Marcusenius macrolepidotus), Pike (Hepsetus odoe), Silverfish (Petersuis rhodesiensis), Broadbar (Nannocharax niloticus), Multi Banded Citharind (Hemigrammocharax multifasciatus) and Spiny Eel (Mastacemblalus mellandi).
The Many Spined Climbing Perch (Ctenopoma multispinis) can be found during the early rains propelling themselves across the wet grasses, using their serrated pectoral fins to travel from one pool to another.
The region has one endemic fish – the Kafue Killifish (Nothobranchius kafuensis) which occupies temporary pool habitats. Females lay eggs in the mud which then hatch when the pools refill during the next rainy season, growing to maturity in a few weeks. Males display to attract females, then grasp her by folding over his large dorsal and anal fins. These killifish are aggressive predators on insects and aquatic invertebrates. They are found in small pools in the Kafue eco-system, in the lower parts of the Upper Zambezi system and in Kafue National Park.
The Luangwa River rises in the Lilonda and Mafina Hills in the north-east, at an elevation of about 1500 m and flows 770 kms south-east before entering the Zambezi River. As it flows through the Luangwa Valley, it drains many of the smaller rivers in Eastern Zambia, seasonally flooding the habits through North and South Luangwa National Parks. 61 fish species have been recorded with cichlids, cyprindis and elephantfish dominating. One endemic species of killifish, Nothobranchius boklundi, has been found in the seasonal pools on the eastern floodplains of the Luangwa River.
Chambeshi and Luapula Rivers
In the north-east of Zambia the rivers feed into the lakes and swamps that form part of the Congo Basin System. The largest is the Chambeshi River which flows out of the Bangweulu Swamps and joins up with the Luapula River. This then flows about 480 kms until it reaches Lake Mweru. At this point the Mumbatuta and Johnson Falls form barriers to fish during the dry seasons. The waters from Lake Mweru flow through the Luvua River and across the border into the DRC, eventually reaching the Lualaba and Congo Rivers.
This whole river system is home to about 100 different fish species, including five endemic species of Barbus – such as the Barbus lornae in the Chambezi River. It is also home to three Nothobranchius; three elephantfish; nine cichlinds, such as the Orthochromis luongoensis in the Luongo River which is a tributary of the Luapula River; and five catfish, including Chiloglanis productus in the Lunzua and Lufubu Rivers.
Fishing is banned on many of the lakes and rivers from the 1st December until the beginning of March the following year. This ban is to protect the fish during their breeding season. No commercial fishing is allowed in the National Parks and tourists can only fish by licence, with many lodges operating a ‘catch and release’ system, or limiting the amount of fish caught ‘for the pot’ per day.