Common names:
Silver cyprinid
None
Taxonomic tree
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii (ray-finned fish)
Order: Cypriniformes (Carps)
Family: Danionidae (Danios)
Genus: Rastrineobola Fowler 1936
Species: Rastrineobola argentea (Pellegrin, 1904)
Number of Occurrancies: 45
Etymology (based on Sharpf & Lazara, 2019)
- Rastrineobola: a Neobola with rastrum, rake or raker, referring to long, lanceolate gill rakers
- argentea: silvery, referring to silvery coloration on flanks and sides of head
Synonyms:click here to view synonyms
Type locality: Lake Victoria. Syntypes at BMNH British Museum of Natural History (BMNH)
Distinguishing characters for the genus
- Lateral line situated below the middle of flank and caudal peduncal, and a cheek below the eye covered by thin sub-orbital bones (vs. Labeo, Labeobarbus, Garra, and Enteromius: lateral line running along middle of the flank and the caudal peduncle; no sub-orbital bones on the cheek).
- Almost the entire dorsal fin situated above the anal fin (vs. Leptocypris: greater part of the dorsal fin is situated in advance of the anal fin)
Distinguishing characters for species
- 16 gill rakers on the lower part of the first arch (distinction from E. bredoi with 10 or 11 gill rakers on lower part of first arch).
- Lateral line with 48-52 complete scales (distinction from E. bredoi with 35-39 lateral line scales)
- Dorsal fin with II-III, 7 or 8 rays, its origin above of the anal which has II-III, 14-17 branched rays(distinction from E. bredoi with 11-13 anal fin rays).
- Depth of body contained 4-5 times in standard length, length of the head 3.75-4.25 times
- Snout pointed, somewhat shorter than the eye which is contained 3.5-4 times in head length
- A large terminal mouth, extending to below the anterior border of the eye.
- Colour is intensely silver, often with an overall nacreous sheen. After death a fairly distinct dark mid-lateral stripe appears. Caudal fin yellow, other fins colourless.
Taxonomic remarks: This species resembles Engraulicypris bredoi in Lake Albert, but differs on the number of lateral line scales, gill rakers on the first arch, and anal fin rays.
Distribution in Uganda: Lakes Victoria, Kyoga, Nabugabo; the Victoria Nile
Occurence: Native
Habitat: Pelagic; present in both inshore and offshore waters; as well fast-flowing waters of rivers
Feeding: Primarily zooplanktivore, but can also feed on surface insects (Mangeni et al., 2018)
Biology: A schooling species which rarely exceeds 8 cm. The species spawns in the lake and produces floating eggs. This is not common with freswater fishes whose eggs are normally heavier than water. There has been notable changes in species life history over the past few decades, including shrinking in body size by 50%, and length at 50% maturity by 27% between the 1970s and 2015 due to fishing and predation by Nile perch. The decline have been more pronounced in males than females (Mangeni et al., 2018).
Economic importance/End use: The species is of great commercial importance, especially in Lakes Victoria and Kyoga. In Lake Victoria, approximately 170,000 tonnes of R. argentea are harvested from the Ugandan side of Lake Victoria; this is worth US$ 93 million from direct sales at landing sites (LVFO, 2016).
IUCN conservation status: click here to view IUCN status
Threats: Overfishing; predation by Nile perch
Main references
- Greenwood PH. 1966. The fishes of Uganda. The Uganda Society, Kampala. 131 pages.
- Sharpf C, Lazara J.K. 2019. Fish Name Etymology Database v4. www.etyfish.org
- LVFO, 2016. Regional Catch Assessment Survey Synthesis Report June 2005 to December 2015. Lake Victoria Fisheries Organization (LVFO), Jinja, Uganda.
- Mangeni-Sande R, Taabu-Munyaho A, Ogutu-Ohwayo R, Nkalubo W, Natugonza V, Nakiyende H, Nyamweya C, Muwanika V. 2018. Spatial and temporal differences in life history parameters of Rastrineobola argentea (Pellegrin, 1904) in the Lake Victoria basin in relation to fishing intensity. Fisheries Management and Ecology. DOI: https://doi.org/10.1111/fme.12281
