The reproductive biology of Brycinus nurse (Paugy 1986), Pisces:-characidae in asa reservoir, Ilorin, Nigeria

A total of 980 specimens of Brycinus nurse caught in Asa reservoir from November 1991 to October 1993 were examined for reproductive attributes. Female dominance was observed within the population, with a sex ratio of 1.0 male to 1.78 females. The fish spawns during the rainy season from March to August, with peak spawning in March, June and July, months coinciding with the onset of the rains and flooding. The Gonadosomatic Index (G.S.I) of the population ofB.nurse in Asa reservoir ranged between 0.02-29.25% with a mean of 6.43 varying with season, size offish, sex and stage of gonadal maturity. The absolute fecundity ranged between 1,720 - 68,700 eggs with a mean of 18,281 eggs while relative fecundity ranged from 19,933 to 849,453 eggs /kg with a mean of 345,000 eggs /kg of body weight. The fecundity increased with gonad weight, but showed no significant relationship with body size. Egg diameter ranged from 0.49 to 0.82 mm with a mean of 0.63 mm. The River Asa population of B.nurse had lower mean values of G.S.I, egg diameter, and relative fecundity but higher estimates of absolute fecundity than other populations, previously studied. These differences were thought to have emanated from differences in geographical location.

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Adebisi, A.A 1987. The relationship between fecundities, gonadosomatic indices and egg sizes of some fishes in Ogun River, Nigeria. Arch Hydrobiol 3(1):151-156.

Albaret, J.J. 1980. La reproduction des poissons d' nou douce de cote d' Ivoire (Sous presse)

Baylis, J.R. 1974. The behaviour and ecology of Herotilapia multispinesa (Teleostei, cichlidae). Z. Tier Psychol. 34:115 - 145

Blache, J. 1964. Les poissons du Bassin du Tchad ET du Bassin adjacent du Mayo Kebbi. Mem. O.R.S.T.O.M. 4: 1-483.

Daget, J. 1952. Memories sur la biologie des poisons du Nigeri Moyen I'biologie et croisance des especes du genre Alestes. Bull. IFAN. 14 (1): 191 - 225

Daget, J. 1957. Donnees recentes dur la biologie des poissons dans le delta central du Niger. Hydrobiologia. 9(4): 321-341

Fagade, S.O, Adebisi, A.A and Atanda, A.N. 1984. The breeding cycle of Sarotherodon galilaeus in the I.I.T.A Lake, Ibadan, Nigeria. Arch. Hydrobiol. 100(4): 493 - 500

Greenwood, P.H. 1955. Reproduction in the catfish Clarias mossambicus. Peters. Nature London. 176:516 -518.

Ham, R. 1981. The ecology of six native and two introduced fish species in Enoggera creek system, south east, Queens land. Bsc. (Hons) Thesis. Griffith Univ. Brisbane. 157

Harding, D. 1966. Lake Kariba: The hydrology and development of fisheries. In: Manmade Lakes. (Ed. R.H. Lowe Mc Connel). Academic Press, London.

Imevbore, A.M.A. 1970. Some general features of Kainji reservoir basin. Kainji lake studies. Vol. 1 Ecology. Ed. S.A. Visser : 17 - 26.

Ita, E.O., Sado, E.K., Balogun, J.K., Pandogari, A. and Ibitoye, B. 1985. Inventory survey of Nigerian Inland waters and their fishery resources. I. A preliminary checklist of Inland water bodies in Nigeria with special reference to ponds, lakes, reservoirs and major rivers. K.L.R.I. Tech. Report series No. 14, Kanji Lake Research Institute, New Bussa, Nigeria.

Kesteven, G.L. 1960. Manual of field Methods in Fisheries Biology. F.A.O Man fish. Sci. No 1: 152.

Kramer, D.L. 1978. Reproductive seasonality in the fishes of a tropical stream. Ecology 59: 976 - 985

Lowe Mc Connel, R.H. 1969. The cichlid fishes of Guyana, South America, with notes on their ecology and breeding behaviour. J. linn. Soc 200 48: 255 - 302.

McKaye, K.R. 1977. Competition for breeding sites between the Cichlid fishes of Lake Jiloa, Nicaragua. Ecology 58: 291 - 302.

Omotosho, J.S. 1990. Some aspects of the biology and distribution of fats in Alestes nurse (Ruppell). Nig. J. Sci (in press.)

Paugy, D. 1980. Ecologie ET biologie des Alestes nurse (Pisces Characidae) des rivieres de Cote d'Ivoire. Cah O.R.S.T.O.M. ser Hydrobiol. 13 (3-4) : 143 - 149.

Paugy, D. 1986. Revision systemtique des Alestes ET Brycinus africanis (Pisces, Characidae). Editions de I'O.R.S. T.O.M, Paris, Etudes ET Theses, 29

Planquette, P. and Lemasson, J. 1975. Le peuplement de poissons du Bandam blan en paye Baole. Ann. University of Abidjan. ser. E. (Ecologie). 8(1). 77-121.

Reed, W.J., Buchard, A.J., Hopson, J., Jennes, J. and Yaro, I. 1967. Fish and fisheries of Northern Nigeria. Ministry of Agriculture, Northern Nigeria, 226

Reizer, C., Mattei, X. and Chevalier, J.L. 1972. Contribution a' l' etude de la faune ichetyologique du bassin du fleure senegal. 11 characidae. Bull. I.F.A.N.A. 34(3) : 651 - 691.

Reynolds, J.D. 1973. Biology and fishery potential of four species of Alestes (Pisces, Characinidae) in the new Volta Lake, Ghana. Rev. Zool Bot. Afri. 8(2) : 298 -310.

Roest, F.C. 1974. Les populations piscicoles du lac de kossou en 1972 - 74 project. P.N.U.D. / A.V.B / F. A.O. Ivc. 26 Rapp. Tech. 24, 53p

Simpson, A.C. 1951. The fecundity of the plaice. Fishery Invest. Loud 11: 17 - 21.

Vanderwaals, B.C.W. 1974. Observations on the breeding habits of C. gariepinus (Burchell). J. Fish Biol. 6.

Ward, J.A. and Samarakoon, J.I. 1981. Reproductive tactics of the Asian cichlids of the genus Etrophus in Srilanka. Envir. Biol. Fish 6: 95 - 103.

Whitehead, P.J.P. 1959. The anadromous fishes of the Lake Victoria. Rev. Zoon. Bot Afri. Lix 34:329 - 363.

Zaret, T.M. 1980. Life history and growth relationships of Cichla Ocellaris, a predatory South American Cichlid. Biotropica 12: 144 - 157.