Jackson and a great footnote and postscript because of the G

Jackson and a great footnote and postscript because of the G

Fryer, G., 1965 Predation and its effects on migration and speciation in African fishes: a comment with further comments by P.H. Greenwood, a reply by P.B.N. Fryer. Proc.Zool. Soc.Lond., 2

Fryer, Grams. and you may T.D. Iles, 1972 The latest cichlid fishes of your Higher Ponds out-of Africa. Edinburgh, Oliver and Boyd, 641p.

Gee, J.M., 1969 A comparison of certain aspects of the biology of Lates niloticus (L) in endemic and introduced environments in East Africa, in Man-Made lakes: the Accra Symposium, ed. L.E. Obeng, Ghana Univ. Press: 2519

Graham, Yards., 1929 New Victoria Nyanza and its Fisheries. A post on brand new Fisheries Survey from River Victoria, 19271928. Top Representatives, London.

Hollawell, J.M., 1972 The growth, reproduction and food of the roach Rutilus rutilus (L) of the River Lugg, Herefordshire. J.Fish.Biol., 4:46986

Hopson, A.J., 1972 A study of the Nile perch Lates niloticus (L.) in Lake Chad. Foreign and Commonwealth Office: London HMSO Overseas Res. Pub.,

Hopson, A.J., 1975 Preliminary observations on the biology of Lates niloticus in Lake Rudolf. Symposium on Hydrobiology and fisheries of Lake Rudolf, Molo 25 29 May, 1975.

Hunter, J.G., 1970 Observations on the taxonomy and biology of Lates (Cuvier, 1928) in Lake Albert. Uganda Occasional Papers No.3

Kudhongania, A.W. and A.J. Cordone, 1974 Bathospatial distribution patterns and biomass estimates of major demersal fishes in Lake Victoria. J.Trop.Hydrobiol.Seafood., 3:1531

Linne) inside the River Victoria and you may Kioga

Lock, J., 1975 Some preliminary results in the investigation of Bagrus bayad. Symposium in the Hydrobiology and Fisheries of Lake Rudolf. Molo 25 29 May, 1975.

Moore, J.W. and I.A. Moore, 1976 The basis of food selection in some estuarine fishes. Eels, Anguilla anguilla (L), whiting, Merlangius merlangus (L), sprat, Sprattus sprattus (L.) and stickleback, Gasterosteus esculeatus L. J.Fish.Biol., 9:37590

Ochieng, J., 1982 Reproductive biology and feeding ecology of a predatory siluroid catfish: Bagrus docmac Forskaal (Pisces: Bagridae) in datingranking.net/pl/willow-recenzja/ Winam Gulf of Lake Victoria: E. Africa. M.Sc. Thesis, University of Nairobi.

Oreochromis niloticus

Ogari, J., 1984 The biology of Lates niloticus (L) in the Nyanza Gulf of Lake Victoria (Kenya) with special reference to the food and feeding habits.

Popova, O.A., 1978 The role of Predaceous Fish in Ecosystems. Inside the S.D Gerking (ed.). Ecology of freshwater fish production, New York, Wiley, p 21549

Stroud, Roentgen.H. and H. Clepper, 1978 Predator-Prey Expertise into the Fisheries Management. Around the world Symposium toward Predator-Target Systems inside Seafood Teams in addition to their Part inside the Fisheries Government. Atlanta, Georgia, July 2427, 1978.

Predatory fishes are able to consume cylindrical-shaped fishes which are of a larger size than the deep bodied fish which they may also prey upon. An effective combination of strong fin spines and a deep body probably protects from most of the predators in Lake Victoria. In Lake Kioga, fishermen have reported the appearance of Nile perch floating dead on the surface and in many cases a large has been found stuck inside the buccal cavity of the predator (Okedi, 1970). The shape and movements of long posterolateral spines in the rotifer Brachionus calyciflorus significantly decreases predation by Asplanchna (Wetzel, 1975). Wetzel (Op. cit.) found that adult Asplanchna sieboldi could capture nearly 100% of adult spineless B. calyciflorus contacted, but only about 78% of the long spined forms. Synodontis species which occur in Lake Victoria have a boney head region provided with stout spines on both pectoral and dorsal fins. When opened, these spines effectively increase the size of the fish thus making them more difficult to swallow and restricting their availability to larger predators. Hopson (1972) observed that Synodontis preyed upon by Lates niloticus in Lake Chad rarely exceeded 18% of the predators length. He also reported finding a dead Nile perch with a Synodontis jammed in its throat.

Figure 1. Diet of L. niloticus in 10 cm size groups assessed by percentage occurrence method. Figures in parenthesis are sample sizes.

Percentage occurrence of food items in the stomach of L. niloticus from five depth strata. Figures in parenthesis are sample sizes.

Kudhongania and Cordone (1974) noted that the best catches of both Haplochromis and Bagrus were within a 1060m depth range, and, from these results, concluded that Bagrus follows Haplochromis more closely than any other species, in terms of relative abundance, depth preference and diel vertical movements. Lock (1975) pointed out that vertical migration appeared to be an adaptation to maintain Bagrus bayad in contact with its prey in Lake Turkana. Echosounding in Lake Kivu has indicated that regani lives in shoals that disperse at dusk and reform at dawn (Fryer and Iles, 1972). Bagrus docmac seems to be most active during the transition between day and night when prey shoals are either forming or breaking up. Most of the prey items in Lake Victoria are probably either diurnal (pelagic species) or nocturnal (mainly demersal species) and are ill-equipped for rapidly changing conditions that prevail during the transition periods both in the evening and morning.

Coulter, G.W., 1976 The biology of Lates species in Lake Tanganyika and the status of the pelagic fishery for Lates species and Luciolates stappersii (Blgr.) J. Fish.Biol., 9:23559