White steenbras  (Lithognathus lithognathus)

The white steenbras is classified as Least Concern (LC) on the IUCN Red List (1).

Often shimmering with a mother-of-pearl sheen, the white steenbras (Lithognathus lithognathus) is a silvery-grey fish, with a whiter underside (3). Seven dark vertical bars pattern each side of the rather elongated body (3), which are often darker in younger, smaller white steenbras (2). It has a long snout and a narrow mouth surrounded by thick lips, and the jaws bear tiny teeth (3).

The white steenbras occurs only in South Africa, where it is found from the Orange River to southern KwaZulu-Natal (2).

Small, juvenile white steenbras can be found in shallow water in estuaries, while larger juveniles typically occur in the surf zone areas of sandy beaches. Adult white steenbras are found in coastal waters down to a depth of 25 metres (2).

This often solitary fish has a remarkable manner of feeding. To obtain its diet of shrimps, worms, small crabs, periwinkles and other molluscs, the white steenbras blows a strong jet of water into the burrow in which the animal lives. This jet stream, created by the pumping action of the powerful gill covers forcing water through the narrow mouth, effectively blows the prey from its shelter (3). In extremely shallow water, the tail of the white steenbras is often seen poking through the water’s surface, as it works, snout down, to blast prey out of the sandy or muddy substrate (3).

Following a summer spent near the Western Cape, the white steenbras migrates to the eastern coasts of South Africa where it is known to spawn from June to August (2) (3). After the fertilisation and hatching of the eggs, the resulting juveniles enter estuaries. Here they will remain, certainly for the first year of their life, sometimes staying for over two years (2). The white steenbras is sexually mature at about six years of age, and around 65 centimetres in length, at which time it moves from the surf zone areas of beaches into deeper coastal waters (2).

This popular food fish, and favourite of anglers, was once abundant around the coasts of South Africa, but numbers have now been severely reduced (4) (5). Both over-fishing and habitat degradation are held responsible for the decrease in both commercial and recreational catches of this species off the Eastern Cape coast (4) (5). The dependence of juvenile white steenbras on estuarine habitats makes them highly vulnerable to habitat degradation, as estuaries are typically greatly affected by the activities of humans, while the tendency of this species to aggregate when spawning makes it vulnerable to heavy fishing pressure (4).

Measures are now in place to help ensure the future survival of this valuable South African species (4). The white steenbras is a protected species in South Africa (3), and severe fishing restrictions have been implemented (4), including a minimum catch size of 40 centimetres (3).

View information on this species at the UNEP World Conservation Monitoring Centre.

For further information on sustainable seafood in Southern Africa:

• The Southern Africa Sustainable Seafood Initiative:
  http://www.wwfsassi.co.za/?m=1