Feeding ecology of tiger fish, (Hydrocynus vittatus) in the Kalimbeza Channel on the Zambezi River, Namibia

Authors

  • Simasiku EK Department of Wildlife Management and Ecotourism, Katima Mulilo Campus, University of Namibia, Private Bag 1096, Ngweze, Katima Mulilo, Namibia.
  • Mafwila SK Department of Fisheries and Aquatic Sciences, and Sam Nujoma Marine and Coastal Resources Research Centre, Sam Nujoma Campus, University of Namibia, P.O. Box 462, Henties Bay, Namibia.
  • Abah J Department of Mathematics, Science and Sport Education, University of Namibia, Katima Mulilo Campus Private Bag 1096, Katima Mulilo, Namibia
  • Hay CJ Department of Biological Science, Main Campus, University of Namibia, Windhoek, Namibia.
  • Matengu KK Research, Innovation, and Development, Main Campus, University of Namibia, Windhoek, Namibia.

Keywords:

Hydrocynus vittatus, piscivory, predation, Zambezi River

Abstract

The feeding ecology of tiger fish, Hydrocynus vittatus (Characidae), in the Kalimbeza Channel on the Zambezi River, Namibia was investigated between February - December 2016. The fish sampling was conducted monthly using cotton multifilament nets with stretched mesh sizes: 12, 16, 22, 28, 35, 45, 57, 73, 93, 118 and 150 mm. A total of 498 specimens of the fish were collected and their stomachs dissected for contents analyses. The findings indicated that large size classes of H. vittatus (>176mm) were largely piscivorous, and showed a diet shift with changes in size. The small size classes of H. vittatus (<140mm) consumed mainly Aquatic insects (21.1%), Synodontis spp (17.8%), and Micralestes acutidens (12.1%). They later shifted to diet in which Synodontis spp (26.1%), Brycinus lateralis (15.2%) and M. acutidens (13.0%) dominated. Seasonal shift in diet were apparent due to changes in seasonal food abundances and distributions. During the wet season, H. vittatus fed mainly on aquatic insects and later showed a shift to diet dominated by fish prey items during the dry season. Hydrocynus vittatus showed no strict food regime and this gives it a better chance of survival. Ratios of prey length-predator length averaged approximately 0.27. The study showed that H. vittatus plays an ecological role with the ability of converting un-exploitable non-commercial species into exploitable protein. Hence their population must be of conservation priority to ensure a balanced fishery in the Zambezi River.

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Published

2017-09-09

How to Cite

Simasiku EK, Mafwila SK, Abah J, Hay CJ, & Matengu KK. (2017). Feeding ecology of tiger fish, (Hydrocynus vittatus) in the Kalimbeza Channel on the Zambezi River, Namibia. International Journal of Life Sciences, 5(3), 297–305. Retrieved from https://ijlsci.in/ls/index.php/home/article/view/1399