A preliminary assessment of the length-weight relationship and condition factor of Hydrocynus vittatus and Oreochromis niloticus in Lake Kariba, Zimbabwe


  • Nyasha Mabika Department of Biological Sciences and Ecology, University of Zimbabwe, Harare, Zimbabwe
  • Rachel Gwazani Department of Livestock, Wildlife and Fisheries, Great Zimbabwe University, Zimbabwe
  • Musara Chipumuro Department Mathematics and Computer Science, Great Zimbabwe University, Zimbabwe
  • Tsitsi Zengeya Department Mathematics and Computer Science, Great Zimbabwe University, Zimbabwe
  • Lawrence Sawunyama Department Mathematics and Computer Science, Great Zimbabwe University, Zimbabwe




Isometric growth, Feeding intensity, Biomass, Morphometric comparison


Background: Hydrocynus vittatus and Oreochromis niloticus are two economically important fish species in Zimbabwe. The length-weight relation can be employed to assess the health and well-being of fish so as to assist fish farmers. The objective of the study was to investigate the length-weight relationship and condition factor of these fish species.

Methods: Thirty-four fish of each species (Hydrocynus vittatus and Oreochromis niloticus) were collected by seine netting in the Sanyati Basin, Lake Kariba in August 2019. The total length (TL) and standard length (SL) were measured in centimetre (cm), and the body weight (BW) was measured in grams (g). The body weight (BW) was measured using a digital top-loading electronic weighing balance.  

Results: The value of the exponent b in the LWR for H. vittatus was 2.984, indicating negative allometry (b<3). The exponent value of O. niloticus in the LWR was 3.04 (b>3) implying positive allometry. The r2 values for H. vittatus and O. niloticus were 92.3% and 97.3% respectively, indicating that there was a high degree of positive correlation. The condition factor for both fish species were greater than 1.60 implying good physiological conditions for both fish species.

Conclusions: This study provides preliminary information on length-weight parameters of O. niloticus whose data was previously not available in the take.


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Abdoli A, Rasooli P. Length-weight relationship of 10 Species of fishes collected from Iranian fresh waters. J Appl Ichthyol. 2008;22:156-7.

Ecoutin JM, Albaret JJ. Relation longueur-poids pour 52 espèces de poissons des estuaires et lagunes de l’Afrique de l’Ouest. Cybium J Ichthyol. 2003;27:3-9.

Sinovcis G, Franicevic M, Zorica B, Cikes-Kec V. Length-weight and length-length relationships for 10 pelagic fish species from the Adriatic Sea (Croatia). J Appl Ichthyol. 2000;20(2):156-8.

Hamid MA, Mansor M, Nor SAM. Length-Weight Relationship and Condition Factor of Fish Populations in Temengor Reservoir: Indication of Environmental Health. Sains Malaysiana. 2015;44:61-6.

Ngodhe SO, Okeyo OJB. Assessment of Length-Weight Relationship and Condition Factor of Nile Tilapia (Oreochromis Niloticus) in Cage and Open Waters in Winam Gulf of L. Victoria, Kenya. Int J Env Sci Natural Resources. 2019;22(3).

Fagade SO. The biology of Cromido tilapia gunteri from a small Lake. Arch. Hydrobiology. 1983;97:60-72.

Welcome RL. Fisheries Ecology of Flood Plain Rivers. Longman Press; London. 1979.

Froese R. Cube law, condition factor and length-weight relationships: History, meta-analysis and recommendations. J Appl Ichthyol. 2006;22:241-53.

Torres FSB. Length-weight relationships of Lake Kariba fishes. NAGA. The ICLARM Quarterly. 1992;15:42-3.

Balon BK, Coche AG. Lake Kariba. A man-made tropical ecosystem in Central Africa. Junk, The Hague. 1974.

Pauly D. Some simple methods for the assessment of tropical fish stocks. FAO Fisheries Technical Paper No. 234. FAO, Rome. 1983.

Ricker WE. Linear regression in fisheries research. J Fish Res. 1973;30:409-34.

Weatherley A, Gill HS. The biology of fish growth. Academic Press, London. 1987.

Moutopoulos DK, Stregiou KI. Length-Weight and Length-Length relationships of fish species from the Aegean Sea (Greece). J Appl Ichthyol. 2002;18:200-3.

Dalu T, Clegg B, Nhiwatiwa T. Length=weight relationships and condition factors of six fish species caught using gill nets in a tropical African reservoir, Zimbabwe. Transac Royal Soc South Afr. 2013;68:75-9.

Nhiwatiwa T. The limnology and ecology of two small man-made reservoirs in Zimbabwe. MPhil thesis, University of Zimbabwe. 2004.

Fafioye OO, Oluajo OA. Length-weight relationship of five fish species in Epe Lagoon, Nigeria, Afr J Biotechnol. 2005;4:749-51.

Bankole NO. Biology study in selected fish species of Tiga Lake Kano State. M.Sc., thesis. Bayero University, Kano. 1989.

Karar AMHM, El-Bassir ARHA, Adam II, Eisa MA, Adam MI. Length-Weight Relationship and Condition Factor of Three Commercial Fish Species of River Nile, Sudan. EC Oceanography. 2017;1:1-7.

Echi PC, Ezenwaji HMG. Length-weight relationships and food and feeding habits of some characids (Osteichthyes: Characidae) from Anambra River, Nigeria. Animal Res Int. 2016;13(1):2316-20.

Barnham C, Baxter A. Condition Factor, K, for Salmonid Fish. Fisheries Notes. 1998;FN005.

Bagenal TB, Tesch FW. Methods of Assessment of Fish Production in Fresh Waters. IBP Handbook No. 3, 3rd edition. Oxford Blackwell Scientific Publication, London. 1978.

Mabika N, Barson M, Van Dyk C, Avenant-Oldewage A. Seasonal occurrence of metazoan parasites in tigerfish, Hydrocynus vittatus Castelnau, 1861 (Characiformes: Alestidae) from Sanyati Basin, Lake Kariba, Zimbabwe. Onderstepoort J Vet Res. 2019;86(1).






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