Common names: Bavhuri (Tshivenda); Baburi (Sepedi); Bavuri (Xitsonga)
Description/How to recognise a Silver butter catfish
Schilbe intermedius, also known as Silver butter catfish, is native to Africa. It is sexually dimorphic, with females growing larger than males. The species reach its maturity at a length of 14 cm in male and 17 cm in female. The silver butter catfish is silver-grey, somewhat darker colour on top and an olive-brown head. It has large shovel mouth surrounded by 4-6 nasal barbs.
Its eyes are slightly protruded from the head. It has a long anal fin, extending from vent almost to the origin of the rear fin. It has four pairs of short, circum-oral barbels. The largest specimen that has ever been documented was 60,5 cm, but normally this species won’t grow much larger than 30 cm.
Silver butter catfish moves moderately slowly but it does move faster when necessary. During the day, the fish prefers to remain stationary at the bottom of the water body.
Water-movements and incidental sound produced as by-product of locomotion maybe used to communicate possible danger to other species. As a response to danger alert, species will move faster in order to escape the danger.
This species is widespread in sub-Saharan Africa from the Senegal River across to Somalia and south as far as the Pongola River in South Africa. In South Africa, it is only found in the northern region (Limpopo and Mpumalanga province) and absent south of Pongola River.
Silver butter catfish is usually found in shallow waters, in both lacustrine and fluviatile conditions. it often shows shoaling habits and seems to prefer large rivers and lakes and seemingly hardly enters small rivers or small affluents. The species usually found at the bottom of the waterbody and migrate to the surface at night to feed in the surface area.
Silver butter catfish is a surface feeder which is active mostly during the night. They feed from mid and surface waters on a wide variety of foods, including small fish, insects, shrimps, snails, freshwater prawns and other crustaceans, algae and bottom-living and planktonic organisms.
Sex and life cycles
Silver butter catfish breed during rainy season. It spawns its eggs on submerged aquatic vegetation. Rainy season creates an opportunity for the spawning of eggs on aquatic vegetation because rainwater overflows river channels into floodplains. Rainy season does not only provides suitable conditions for eggs spawning but also nursery habitats, water oxygenation conditions and food resources for newly hatched larvae.
Spawning lasts from June to November. Larger females spawn before smaller females. The silver butter catfish has high fecundity. They have distinct pairing mating behavior. Silver butter catfish can live up to 10 years.
Because silver butter fish like to stick together, they are usually found in groups of 3 or more.
The bigger picture
Friends and foes
Silver butter catfish is not aggressive. Large silver butter catfish prey on small fish like haplochromine cichlids. The exotic Nile perch introduced to the lakes where the silver butter catfish are original found , compete with silver butter catfish for food and also prey on the smaller ones.
Since females species of Silver butter catfish are larger than males, they are more susceptible to fishing than male species. Even though females are prone to fishing than male, female population never gets exploited because the species reproduce more females than males. The dorsal fin are modified into spines, rendering it dangerous to the opponent when it draw near it.
Poorer world without me
The silver butter catfish is one of the top predators in most lakes, rivers and floodplains where they habit. The species is important in regulating small fish populations in the fresh water ecosystem.
People and I
This species is commercially used in aquaculture and there is heavy fishing pressure, but the species is highly abundant and reproduce many offspring. In eastern Africa the species is also threatened by biotope changes, for example as caused by invasive species. No serious threats have been identified except the overexploitation occurring in three lakes, that is Lakes Victoria, Kyoga and Nabugabo.
Conservation status and what the future holds
The International Union for Conservation of Nature (IUCN) Red List listed Silver butter catfish as a Least Concern species. There are no conservation actions known to be in place up to so far. The population trend should be monitored.
It appears closely related to Schilbe uranoscopus and the two species were once one species but has just split and form a new species. The new species appears different from the original species while the original one still remains. Although the two species still share the same geographic range, the two species have evolved reproduction barrier.
Scientific name and classification
Official common name: Silver butter catfish
Species: Schilbe intermedius Rüppell, 1832
References and further reading
- De Vos, L. (1995). A systematic revision of the African Schilbeidae (Teleostei, Siluriformes). With an annotated bibliography. Ann. Mus. R. Afr. Centr., Sci. Zool., 271, 1-450
- Diouf, K., Geelhand, D. & FishBase team RMCA. 2020. Schilbe intermedius. The IUCN Red List of Threatened Species 2020: e.T181729A135029310. https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T181729A135029310.en. Accessed on 04 May 2022.
- Froese, R. and D. Pauly. Editors. 2022.FishBase. World Wide Web electronic publication. www.fishbase.org, (02/2022)
- Goudswaard, K., & Witte, F. (1997). The catfish fauna of Lake Victoria after the Nile perch upsurge. In Environmental Biology of Fishes (Vol. 49).
- Merron, G. S., & Mann, B. Q. (1995). The reproductive and feeding biology of Schilbe intermedius Riippell in the Okavango Delta, Botswana. In Hydrobiologia (Vol. 308).
- Montcho, S. A., Chikou, A., Lalèyè, P. A., & Linsenmair, K. E. (2011). Population structure and reproductive biology of Schilbe intermedius (Teleostei: Schilbeidae) in the Pendjari River, Benin. African Journal of Aquatic Science, 36(2), 139–145.https://doi.org/10.2989/16085914.2011.589111
- Mutethya, E., Okoth, S., & Yongo, E. (2020). Biological aspects of Schilbe intermedius (Ruppell, 1832) in the Nyanza Gulf of Lake Victoria, Kenya. Lakes and Reservoirs: Research and Management, 25(1), 44–48. https://doi.org/10.1111/lre.12304
Authors: Unarine Mudau and Moleseng Claude Moshobane
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