International Journal of
Fisheries and Aquaculture

  • Abbreviation: Int. J. Fish. Aquac.
  • Language: English
  • ISSN: 2006-9839
  • DOI: 10.5897/IJFA
  • Start Year: 2010
  • Published Articles: 228

Full Length Research Paper

Recent changes in fish communities of the equatorial Lake Naivasha, Kenya

Aloo P. A.
  • Aloo P. A.
  • Department of Aquaculture and Fisheries Management, Karatina University, P. O. Box 1957-10101, Karatina, Kenya.
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Oyugi D. O.
  • Oyugi D. O.
  • Kenya Wildlife Service Training Institute, Kenyatta Avenue, P. O. Box 842, Naivasha, Kenya.
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Morara G. N.
  • Morara G. N.
  • Kenya Marine and Fisheries Research Institute, Mombasa Station, P. O. Box 81651-80100, Mombasa , Kenya.
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Owuor M. A.
  • Owuor M. A.
  • Department of Applied Limnology and Marine Sciences, South Eastern University College, P. O. Box 170-90200 Kitui, Kenya.
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  •  Accepted: 15 March 2013
  •  Published: 30 April 2013

Abstract

Changes in fish species composition and abundance in Lake Naivasha were investigated monthly for a period of 12 months. Data were obtained both from experimental surveys as well as commercial fish landings. The structure metrics considered included species abundance and composition, length- frequency and physico-chemical attributes. Results of the study showed that the fishery is currently dominated by the recently introduced common carp,Cyprinus carpio accounting for over 95% of the total fish landings, with the naturalized fish populations performing dismally both in terms of abundance as well as health conditions. The entry of the common carp into Lake Naivasha may have completely transformed the lake’s ecosystem integrity, driving the initially abundant tilapiine species to near local extinction. The study also confirms a restricted distribution of Micropterus salmoides to rocky-bottomed habitats of Hippo Point and Crescent Lake. Conversely, the long-fin barb, Barbus paludinosus,initially confined to the north swamp and the mouth of River Malewa, currently exhibits a lake-wide distribution. The changing climatic conditions as manifested in the lake level recessions may be a real threat to the fish stocks in the lake. Human activities in the catchment areas may also have contributed to the recent ecological changes witnessed in Lake Naivasha. This study proposes a number of recommendations with a view to ensuring ecosystem integrity and consequent sustainable fisheries of Lake Naivasha.

 

Key words: Ecosystem integrity, habitat preference, species introductions, sustainable fisheries, fish population, equatorial lake.