The West African pygmy herring (''Sierrathrissa leonensis'') is a very small fish, reaching a maximum length of SL. It is a member of the

herring Herring are forage fish, mostly belonging to the family of Clupeidae. Herring often move in large schools around fishing banks and near the coast, found particularly in shallow, temperate waters of the North Pacific and North Atlantic Oceans, i ...

family

Dorosomatidae Dorosomatidae is a family of clupeiform fishes. It is now recognized by FishBase as a family in its own right; it had been considered to be a subfamily of Clupeidae. It contains 31 extant Extant is the opposite of the word extinct. It may re ...

in the freshwater systems of western and central Africa that includes such species as the ''

Microthrissa royauxi ''Microthrissa royauxi'', the royal sprat, is a species of pelagic, freshwater fish from the herring family Clupeidae which is found in the Congo River basin in west Africa. It was described in 1902 by the Belgian-British zoologist George Albert ...

'' of the

Congo River The Congo River ( kg, Nzâdi Kôngo, french: Fleuve Congo, pt, Rio Congo), formerly also known as the Zaire River, is the second longest river in Africa, shorter only than the Nile, as well as the second largest river in the world by discharge ...

basin and '' Limnothrissa miodon'' of Lake Tanganyika. It is the only species of its genus.

Description

A very small fish which shows a reduction in size and some

neoteny Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compared ...

when compared to its larger relatives.

Habitat and ecology

The West African pygmy herring is found in rivers and man-made lakes. It schools in open waters and to a maximum depth of around ; rising to about from the surface at night in

Lake Volta Lake Volta, the largest artificial reservoir in the world based on surface area, is contained behind the Akosombo Dam which generates a substantial amount of Ghana's electricity. It is completely within the country of Ghana and has a surface area ...

. It feeds on plankton, especially cladocerans.

Distribution

The West African pygmy herring has a widespread but patchy distribution from

Senegal Senegal,; Wolof: ''Senegaal''; Pulaar: 𞤅𞤫𞤲𞤫𞤺𞤢𞥄𞤤𞤭 (Senegaali); Arabic: السنغال ''As-Sinighal'') officially the Republic of Senegal,; Wolof: ''Réewum Senegaal''; Pulaar : 𞤈𞤫𞤲𞤣𞤢𞥄𞤲𞤣𞤭 � ...

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ...

. In west Africa it occurs in

Senegal River ,french: Fleuve Sénégal) , name_etymology = , image = Senegal River Saint Louis.jpg , image_size = , image_caption = Fishermen on the bank of the Senegal River estuary at the outskirts of Saint-Louis, Senegal ...

Gambia River The Gambia River (formerly known as the River Gambra) is a major river in West Africa, running from the Fouta Djallon plateau in north Guinea westward through Senegal and The Gambia to the Atlantic Ocean at the city of Banjul. It is navigable f ...

, Bia River,

Niger River The Niger River ( ; ) is the main river of West Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in south-eastern Guinea near the Sierra Leone border. It runs in a crescent shape through ...

basin and

Wouri River The Wouri (also Vouri or Vuri) is a river in Cameroon. Cameroon has two major rivers, the Sanaga, the longest at about 525 km (325 miles) long and the Wouri, the largest. The Wouri forms at the confluence of the rivers Nkam and Makombé, ...

, as well as the man made Lake Volta and

Lake Kainji Kainji Lake, in North Central Nigeria, is a reservoir on the Niger River, formed by the Kainji Dam. It was formed in 1968 and is a part of Niger State and Kebbi State. Kainji Lake National Park (KNLP), situated around the lake, is Nigeria's oldes ...

. This species is native to Cameroon,

Ivory Coast Ivory Coast, also known as Côte d'Ivoire, officially the Republic of Côte d'Ivoire, is a country on the southern coast of West Africa. Its capital is Yamoussoukro, in the centre of the country, while its largest city and economic centre is ...

Ghana Ghana (; tw, Gaana, ee, Gana), officially the Republic of Ghana, is a country in West Africa. It abuts the Gulf of Guinea and the Atlantic Ocean to the south, sharing borders with Ivory Coast in the west, Burkina Faso in the north, and To ...

Nigeria Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...

, Gambia, Senegal and

Sierra Leone Sierra Leone,)]. officially the Republic of Sierra Leone, is a country on the southwest coast of West Africa. It is bordered by Liberia to the southeast and Guinea surrounds the northern half of the nation. Covering a total area of , Sierra ...

Fisheries and conservation

As the West African pygmy herring has a widespread distribution and is short lived with high resilience to exploitation, it is therefore listed as Least Concern. In Nigeria this species is subject to some commercial fishing for human consumption.

Taxonomy

The West African pygmy herring was first species description, described from Sierra Leone, but this was somewhat controversial and claims were made that the specimens were nothing more than the unmetamorphosed larva of a species of ''

Pellonula ''Pellonula'' is a small genus of fish in the herring family, Clupeidae. There are currently two recognized species in this genus. Both species of this genus are native to Africa. Species * ''Pellonula leonensis'' Boulenger, 1916 (Small-toot ...

'' or of '' Cynothrissa''. However, when fully mature specimens of ''Sierrathrissa'' were described at 21-28mm SL, it was clear that these were not juveniles of other species.

References

{{Taxonbar, from=Q3759469 West African pygmy herring Freshwater fish of West Africa West African pygmy herring