THE HABITATS AND HABITAT PREFERENCES OF CLARIAS GARIEPINUS (PISCES: CLARIIDAE) IN A CLEAR COASTAL LAKE (LAKE SIBAYA, SOUTH AFRICA)

SUMMARY

The habitat preferences of the sharptooth catfish, Clarias gariepinus, in a clear coastal lake, Lake Sibaya, are described. Larval and small juvenile catfish inhabit flotsam and the rootstocks of plants in very shallow marginal areas. Larger juveniles inhabit densely-vegetated marginal pools, and may venture into open areas at night. Adult catfish (over 350 mm TL) occupy offshore areas, where their density is highest in terrace and sheltered bay habitats, and least in slope and profundal habitats. Adult catfish undergo a diel migration into shallow water at night and into deeper water during the day which is more marked at low lake levels. The methods used to capture catfish, and the main habitats in Lake Sibaya, are also described.

KEY WORDS:

• Clarias gariepinus
• habitats
• habitat preferences
• clear lake
• coastal lake
• catfish
• migration