Largescale Yellowfish
Labeobarbus marequensis
Lowveld Largescale Yellowfish
Shortsnout Chiselmouth

Max length:          40.0 cm – 65cm
Record Size:        5,75 kg Crocodile Riber 6,00 kg Pongholo River

The largest recorded weighed 10 Kg. This was caught in 1980 by Casper Dercksen at Beja Bridge, inlet of Albasini dam.

Climate / Range Tropical:

11°S – 27°S

Habitat:

Abundant in suitable rocky, fast flowing habitats. Prefers flowing waters of perennial rivers. Uncommon in dams. Feeds on a wide variety of food items, primarily algae and aquatic insect larvae; also takes small fishes, snails, freshwater mussels and drifting organisms such as beetles and ants. Breeds in spring and summer, migrating upstream in rain swollen rivers to spawn in rapids. Males mature at 70 cm FL, females mature at 28 cm FL. Occurs with the small-scale yellow fish in many rivers across Gauteng, Mpumulanga and Limpopo rivers.

Threats:
Affected by weirs and dams and habitat degradation.

Please look after our threatened species. When you hold a live fish the future is in your hands

For more information please visit the
IUCN Red List of Threatened Species website
www.iucnredlist.org/
IUCN Red List Unit
IUCN UK Office, 219c Huntingdon Road
Cambridge CB3 0DL, United Kingdom

Extract from: TECHNICAL REPORT ON THE STATE OF YELLOWFISHES IN SOUTH AFRICA 2007 – Compiled by the Yellowfish Working Group for the Water Research Commission.

The full document is obtainable from:
Water Research Commission
Publications
Private Bag X03
Gezina, Pretoria
0031 SOUTH AFRICA
orders@wrc.org.za[/size]

Two of its main rivers, the Crocodile and Marico, give rise to the Limpopo River at their confluence. The climate is generally semi-arid and the mean annual rainfall ranges from 400 mm to 800 mm. Extensive irrigation occurs along the main rivers whereas grain, livestock and game farming are the principal forms of agriculture in the remainder of the area. The urban and industrial complexes of northern Johannesburg and Pretoria and platinum mining north-east of Rustenburg dominate economic activity in the region.

It is the second-most populous WMA in the country and economically the most active.

Development and utilisation of surface water occurring naturally in the water management area has reached its full potential. A small amount of water is transferred from this WMA to Gabarone in Botswana as well as to Modimole in the Limpopo WMA. Increasing quantities of 50 effluent return flow from urban and industrial areas are a major cause of pollution in several rivers.

The Crocodile, Apies-Pienaars, Elands, Marico and Molopo are the major rivers within the WMA. The environmental agencies of Limpopo, Gauteng and North West Provinces share the responsibility for the rivers. A coordinated survey by the three provinces, which resulted in a State of the Rivers Report (SoRR) for the Crocodile-West River, represents the most recent data on the species. L. marequensis was not found in six of the 16 historic sites.

Despite anthropogenic pressures on Gauteng rivers, it is still widespread and common in stretches of river that have acceptable habitat diversity, water flow and quality. Until recently, it was relatively common in the Jukskei River within greater Johannesburg indicating adaptability and fair tolerance of human impacts.

Growth rate and longevity

Very little is known about the growth rate of the species (Russell, 1997). Göldner (1969) found that in Loskop Dam the fish attained a fork length of 110 mm at the end of the first year and 150 to 160 mm at the end of the second year. Females grow faster, attain a greater length and on average become older than males (Gaigher, 1969), a detail underpinned by Göldner (1969) who found females to be three times more abundant than males. Gaigher (1969) established that the size obtained by the fish was related to their distribution and to altitude in particular. Above 610 m the dominant fork length was 160 mm whereas at lower altitudes it frequently reached 300 mm.

Diet

Various authors (Crass, 1964; Pienaar, 1978; Gaigher, 1979; Bell-Cross and Minshull 1988; Skelton, 2001) regard the species as omnivorous as it feeds mostly on algae, plant detritus, immature and adult aquatic insects, snails and even small fish. Fouché et al. (2003) confirmed the findings of Gaigher (1969) and Skelton (2001) that algae formed the bulk of the diet of fish smaller than 60 mm. Fouché and Gaigher (2001) found that the relative gut length of L. marequensis was 2,24 times longer than its fork length, a feature typical of herbivorous fishes.

The full document is obtainable from:
Water Research Commission
Publications
Private Bag X03
Gezina, Pretoria
0031 SOUTH AFRICA
orders@wrc.org.za[/size]