''Alestes baremoze'', the pebbly fish or silversides, is a species of
characin
Characiformes is an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, more than 2000 different species are described, including the well-known piranha and tetras.; Buckup P.A.: "Relationshi ...
fish from the freshwater systems of northern and western Africa. It has some importance as a commercially exploited food fish.
Description
''Alestes baremoze'' is a silver-coloured fish with a bluish-grey dorsum and a white belly, the fins are greyish with an orange coloured lower lobe of the
caudal fin
Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...
. The maximum published length is 43 cm and the maximum published weight is 500g, although sexual maturity is reached at about 20 cm. It belongs to order Characiformes, family Alestidae, and genus ''
Alestes
''Alestes'' is a genus in the family Alestidae, known as the "African Characidae" as they are found exclusively on that continent. As suggested by that name, they Alestidae was formerly included in Characidae. ''Myletes'' is a synonym of ''Aleste ...
''. Histomorphological observations and stomach content analysis
suggested that ''A. baremoze'' has morphological adaptations for omnivory
Distribution
In eastern Africa it is found within Lake Albert, the
White Nile
The White Nile ( ar, النيل الأبيض ') is a river in Africa, one of the two main tributaries of the Nile, the other being the Blue Nile. The name comes from the clay sediment carried in the water that changes the water to a pale color. ...
and
Lake Turkana
Lake Turkana (), formerly known as Lake Rudolf, is a lake in the Kenyan Rift Valley, in northern Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's largest alkaline lake. B ...
. In Northern Africa ''Alestes baremoze'' was formerly distributed along the whole of the
River Nile
The Nile, , Bohairic , lg, Kiira , Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the longest rive ...
in
Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...
, including the
Nile Delta
The Nile Delta ( ar, دلتا النيل, or simply , is the delta formed in Lower Egypt where the Nile River spreads out and drains into the Mediterranean Sea. It is one of the world's largest river deltas—from Alexandria in the west to Po ...
lakes,
Rosetta
Rosetta or Rashid (; ar, رشيد ' ; french: Rosette ; cop, ϯⲣⲁϣⲓⲧ ''ti-Rashit'', Ancient Greek: Βολβιτίνη ''Bolbitinē'') is a port city of the Nile Delta, east of Alexandria, in Egypt's Beheira governorate. The Ro ...
Branch and Lower Nile, but it has now been confined to the upper Nile after the construction of the Aswan High Dam, and no longer occurs in northern Egypt. ''Alestes baremoze'' occurs in the
Bahr el Ghazal River
The Bahr el Ghazal (; also spelled Bahr al Ghazal and Baḩr al Ghazāl) is a river in South Sudan. The South Sudanese region of Bahr el Ghazal takes its name from the river.
The Bahr el Ghazal is the main western tributary of the Nile. It is l ...
and Bahr el Jebel systems; the
White
White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White on ...
and
Blue Nile
The Blue Nile (; ) is a river originating at Lake Tana in Ethiopia. It travels for approximately through Ethiopia and Sudan. Along with the White Nile, it is one of the two major tributaries of the Nile and supplies about 85.6% of the water ...
s in
Sudan
Sudan ( or ; ar, السودان, as-Sūdān, officially the Republic of the Sudan ( ar, جمهورية السودان, link=no, Jumhūriyyat as-Sūdān), is a country in Northeast Africa. It shares borders with the Central African Republic t ...
, north to
Lake Nasser
Lake Nasser ( ar, بحيرة ناصر ', ) is a vast reservoir in Southern Egypt and northern Sudan. It is one of the largest man-made lakes in the world. Before construction, Sudan was against the building of Lake Nasser because it would encro ...
. It has also been recorded in
Ethiopia
Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...
's
Baro River
The Baro River ( am, ባሮ ወንዝ) or Baro/Openo Wenz, known to the Anuak as Openo River, is a river in southwestern Ethiopia, which defines part of Ethiopian border with South Sudan. From its source in the Ethiopian Highlands it flows west ...
. It is widespread in West Africa in the basins of
Chad
Chad (; ar, تشاد , ; french: Tchad, ), officially the Republic of Chad, '; ) is a landlocked country at the crossroads of North and Central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic ...
Bandama
The Bandama River is the longest river in Ivory Coast with a length of some 800 kilometers. The south-flowing river is fed by the Marahoué, Solomougou, Kan and Nzi rivers and empties into the Tagba Lagoon and the Gulf of Guinea.
The Bandama fl ...
,
Sassandra
Sassandra is a town in southern Ivory Coast. It is a sub-prefecture of and the seat of Sassandra Department. It is also a commune and the seat of Gbôklé Region in Bas-Sassandra District.
Sassandra lies on the Gulf of Guinea at the mouth of th ...
Gambia
The Gambia,, ff, Gammbi, ar, غامبيا officially the Republic of The Gambia, is a country in West Africa. It is the smallest country within mainland AfricaHoare, Ben. (2002) ''The Kingfisher A-Z Encyclopedia'', Kingfisher Publicatio ...
''Alestes baremoze'' is mainly diurnal and is mainly found in the inshore zones of lakes, but is also shows
potamodromous
Fish migration is animal migration, mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few ...
and
benthopelagic
The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...
behaviour. It is a rather generalist feeder with considerable flexibility in its diet, shifting from
zooplankton
Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...
to
zoobenthos
Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone.macrophytes
Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that g ...
as the density of plankton declines. When breeding both sexes occur in sheltered bays on lake shores. Non breeding adults migrate upriver from lacustrine environments when the rivers are in flood, where they gather in shoals and feed.
Nutrition
''Alestes baremoze'' commonly known as Angara in Uganda is highly marketable and valued fish in Northern Uganda, South Sudan, Sudan and in the Democratic Republic of Congo. Many consumers, especially in the West Nile region appreciate the taste, special flavour and texture characteristics of this fish. Salting is not only a method to prolong shelf life, but a method to produce fish products that meet demand of consumers. The crude protein values of A. baremoze according to different sizes were reported to be in the range of (17-18%) and zinc was the most abundant micro element while potassium was found to be the macro-mineral with highest concentration.kasozi et al., 2014.Proximate composition and mineral contents of Pebbly fish, Alestes baremoze (Joannis, 1835) fillets in relation to fish size.Uganda Journal of Agricultural Sciences
In
Lake Chad
Lake Chad (french: Lac Tchad) is a historically large, shallow, endorheic lake in Central Africa, which has varied in size over the centuries. According to the ''Global Resource Information Database'' of the United Nations Environment Programme, ...
spawning takes place from in the late afternoon and evening, between 16:30-20:00 h. The eggs are shed in a single batch which represents 15% of the weight of female. When spawning the mature females are dispersed and do not form groups.
Fisheries
''Alestes baremoze'' is caught and salted in the Nile, especially in Egypt. On Lake Chad it is caught in
seine net
Seine fishing (or seine-haul fishing; ) is a method of fishing that employs a surrounding net, called a seine, that hangs vertically in the water with its bottom edge held down by weights and its top edge buoyed by floats. Seine nets can be dep ...
s and
gill net
Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a line with regularly spaced floaters that hold the line on the surface of the water. The floats are sometimes called "corks" and the line with corks is ...