Hydrobiologia 407: 131–139, 1999. O. V. Lindqvist, H. Mölsä, K. Salonen & J. Sarvala (eds), From Limnology to Fisheries: Lake Tanganyika and Other Large Lakes. © 1999 Kluwer Academic Publishers. Printed in the Netherlands. 131 Feeding ecology of Lates stappersii in Lake Tanganyika Piero Mannini 1 , Ibrahim Katonda 2 , Balthazar Kissaka 2 & Piet Verburg 3 1 FAO Lake Tanganyika Research Project, P.O. Box 90 Kigoma, Tanzania Present address: Via D. Martelli 14/A, 57012 Castiglioncello (LI), Italy 2 TAFIRI, P.O. Box 90 Kigoma, Tanzania 3 FAO Lake Tanganyika Research Project, P.O. Box 55 Mpulungu, Zambia Key words: Lake Tanganyika, clupeidae, centropomidae, feeding ecology Abstract The centropomid Lates stappersii and its prey, the clupeid Stolothrissa tanganicae, make up the main exploited pelagic fish resource of Lake Tanganyika. In the south of the lake the contribution of S. tanganicae in the industrial fishery drastically declined during the 1980s while the catch of L. stappersii has increased to consist most of the yield. Lates stappersii does not seem to be affected by the decreased abundance of the clupeid prey. The analysis of the stomach contents of captured L. stappersii in the southern and north-eastern areas of the lake indicated a different feeding ecology for the fish between areas. Pelagic shrimps were the main prey species in the south while in the north-east the diet was more heterogeneous and included S. tanganicae larvae and adults, shrimps and copepods. It appears that the commercially important stock of L. stappersii in the south is sustained by shrimps which have replaced the clupeids in the diet. Introduction The pelagic fishery of Lake Tanganyika is based on the clupeid species Stolothrissa tanganicae and on its main predator, the centropomid Lates stappersii. In addition, the clupeid Limnothrissa miodon is also caught. Exploitation differs between the north and south. The fishery concentrates on clupeids (mainly S. tanganicae) in the north, on L. stappersii in the south and on both clupeids and centropomid in the Kigoma area (Mannini et al., 1996). Previous investigations showed the importance of shrimp as prey in the southern areas (Pearce, 1985, 1995), but no lake-wide study has been carried out to show whether this is typical in all regions. Lates stappersii is believed to be piscivorous throughout its life (Ellis, 1978; FAO, 1978; Roest 1992). The present investigation was carried out to de- termine if differences exist in the feeding ecology of L. stappersii from two distant areas of the lake and whether prey availability reflected in the diet, contribute to the spatial distribution pattern of the species. Materials and methods The collection of fish data at landing sites in the Kigoma (Tanzania) and Mpulungu (Zambia) areas was carried out using the standardized procedures determ- ined by the FAO-FINNIDA regional project ‘Research for the management of the fisheries on Lake Tanga- nyika’ (Aro, 1993; Mannini, 1993). The two sampling localities are about 500 km apart. Kigoma is on the east coast (4 ◦ 51 ′ S, 29 ◦ 37 ′ E) and Mpulungu at the south end of the lake (8 ◦ 45 ′ S, 31 ◦ 06 ′ E). Pela- gic fish were sampled weekly from commercial liftnet and purse seine catches. Hauling operations normally started at about midnight and continued throughout darkness. From March 1994 to June–July 1995 total length (TL, mm), individual body weight (W, g) data and stomachs of L. stappersii were collected from length- stratified subsamples (a maximum of five specimens were taken from each 10 mm length class). The stomachs were preserved in 10% formalin and later prey were identified as precisely as possible (Man- nini, 1994). The food category ‘clupeids’ was used