Synopsis
Age composition, growth and body condition of the Sarotherodon mossambicus (Peters) stock in the Plover Cove Reservoir were investigated. The fish in this reservoir have a relatively short life cycle; the stock consisted of mainly two to three age groups. Influx of recruits in September and October maintained a high proportion of O-age group fish in the stock. This percentage remained high until the following March or April when the I-age group attained dominance. Length-weight analyses indicated that S. mossembicus conform to the allometric formula W = aLn with ‘a’ and ‘n’ exhibiting marked seasonal variations. Growth was most rapid during the first 20 months of life and decreased noticeably after 30 months. In general growth was limited to those months when the water temperature was above 20° C. Both body condition and visceral fat content exhibited seasonal variations which were not correlated with each other or with variations in temperature. However, body condition appears to be directly related to feeding intensity. Mean body condition decreased with increasing age and also decreased progressively during this study. This progressive decrease was probably related to the progressive decrease in salinity of the water and also the carrying capacity of the reservoir rather than to the nutrient content of the water. Mean values for the body condition of females were in general higher than for males, suggesting that females are more robust than males.
Maximum accumulations of fat occurred in June and July, corresponding to the breeding period. Such accumulations are thought to be a prerequisite before spawning.
Similar content being viewed by others
References cited
Bruton, M. N. & B. R. Allanson. 1974. The growth of Tilapia mossambica Peters (Pisces: Cichlidea) in Lake Sibaya, South Africa. J. Fish Biol. 6: 701–715.
Chimits, P. 1955. Tilapia and its culture. F.A.O. Fisheries Bulletin 8: 1–33.
Coe, M. J. 1966. The Biology of Tilapia grahami Boulenger in Lake Magadi, Kenya. Acta trop. 23: 146–177.
Cridland, C. C. 1960. Laboratory experiments on the growth of Tilapia spp. I. The value of various foods. Hydrobiologia 15: 135–160.
Fryer, C. & T. D. Iles. 1969. Alternative routes to evolutionary succes as exhibited by African cichlid fishes of the genus Tilapia and the species flocks of the Great Lakes. Evolution 23: 359–369.
Fryer, G. & T. D. Iles. 1972. The Cichlid Fishes of the Great Lakes of Africa. Their Biology and evolution. Oliver and Boyd, Edinburgh. 641 pp.
Fulton, T. 1902. Rate of growth of sea fishes. Scientific Investigations, Fishery Division of Scotland Report 20.
Hey, D. 1947. The culture of freshwater fish in South Africa. Inland Fisheries Department, Provincial Administration of the Cape of Good Hope. 124 pp.
Hickling, C. F. 1960. The Malacca Tilapia hybrids. J. Genet. 51: 1–10.
Hickling, C. F. 1961. Tropical Inland Fisheries. Longmans, London. 287 pp.
Hickling, C. F. 1963. The cultivation of Tilapia. Scient. Am. 208: 143–152.
Hile, R. 1936. Age and growth of the cisco Leucichthys artedii (Le Sueur) in the lakes of the north eastern highlands, Wisconsin. Bull. US Bur. Fish. 48: 211–217.
Hjort, J. 1914. Fluctuations in the great fisheries of northern Europe. Rapp. Cons. Explor. Mer. 20.
Hodgkiss, I. J., & H. S. H. Man. 1976a. Studies on the ichthyofauna in Plover Cove Reservoir, Hong Kong: I. Sequence of fish population changes. J. Fish Biol. (In press.)
Hodgkiss, I. J., & H. S. H. Man. 1976b. Studies on the ichthyofauna in Plover Cove Reservoir, Hong Kong: II. Feeding and Food relations. J. Fish. Biol. (In press.)
Hodgkiss, I. J., & H. S. H. Man. 1977. Stock density and martality assessment of Sarotherodon mossambicus (Cichlidae) in Plover Cove Reservoir, Hong Kong. Env. Biol. fish. 1: 171–180.
Iles, T. D. 1973. Dwarfing or stunting in the genus Tilapia (Cichlidae); a possibly unique recruitment mechanism. Rapp. R.v.-Reun. Cons. perm. int. Explor. Mer. 164: 247–254.
Koura, R., & A. R. El Bolock. 1958. Age, growth and survival of Tilapia mossambica Peters in Egyptian ponds. Notes Mem. Hydrobiol. Dep. U.A.R. 41: 1–18.
La Touche, M. C. D., A. J. E. Smith, and M. I. Townsend. 1970. Plover Cove Reservoir, Hong Kong. The transition from marine to freshwater conditions. Commission Internationale Des Grands Barrages, Q. 38, R. 51: 981–1004.
Le Cren, E. D. 1951. The length weight relationship and seasonal cycle in gonad weight and condition in the Perch (Perca fluviatilis L.). J. Anim. Ecol. 20: 201–218.
Le Mare, D. W. 1950. The application of the principles of fish culture to estuarine conditions in Singapore. Proc. Indo-Pacif. Fish. Coun. 2: 175–180.
Nikolsky, G. V. 1963. The Ecology of Fishes. Academic Press, London and New York. 352 pp.
Prozorovskaya, M. L. 1952. On the method of determining the fat content of the roach from the quantity of fat on the intestine. Bull. Inst. Fish. USSR. 1.
Schuster, W. H. 1952. Fish culture in brackish-water ponds in Java. Indo-Pacific Fisheries Council (F.A.O.) Special Publications, 1.
Tesch, F. W. 1971 Age and growth. pp. 95–130. In W. E. RickerWaters, I.B.P. Handbook No. 3. Blackwell Scientific Publications, Oxford.
Welcomme, R. L. 1965. Further observations on the biology of the introduced Tilapia species. E. Afr. Freshwat. Fish. Res. Org. Annual Report 1964. 18–24.
Welcomme, R. L. 1970. Studies of the effects of abnormally high water levels on the ecology of fish in certain shallow regions of Lake Victoria. J. Zool. Lond. 160: 405–436.
Whitehead, P. J. P. 1962. The relationship between Tilapia nigra (Günther) and Tilapia mossambica Peters in the eastern rivers of Kenya. Proc. Zool. Soc. Lond. 138: 605–637.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hodgkiss, I.J., Man, H.S.H. Age composition, growth and body condition of the introduced Sarotherodon mossambicus (Cichlidae) in Plover Cove Reservoir, Hong Kong. Environ Biol Fish 2, 35–44 (1977). https://doi.org/10.1007/BF00001414
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00001414