Changes in feeding biology of Nile tilapia, Oreochromis niloticus (L.), after invasion of water hyacinth, Eichhornia crassipes (Mart.) Solms, in Lake Victoria, Kenya

Njiru, M. (1999) Changes in feeding biology of Nile tilapia, Oreochromis niloticus (L.), after invasion of water hyacinth, Eichhornia crassipes (Mart.) Solms, in Lake Victoria, Kenya. In: Report on Fourth FIDAWOG Workshop held at Kisumu, 16 to 20 August 1999. Jinja, Uganda, Lake Victoria Fisheries Research Project, pp. 175-183. (LVFRP Technical Document,7)

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Abstract

Oreochrimis niloticus (L.) was introduced to Lake victoria in the 1950s. It remained relatively uncommon in catches until 1965, when the numbers began to increase dramatically. It is now the third most important commercial fish species after the Nile perch, Lates niloticus (L.) and Rastrineobola argentea (Pellegrin). Oreochromis niloticus is considered a herbivore, feeding mostly on algae and plant material. The diet now appears to be more diversified , with insects, fish, algae and plant materials all being important food items. Fish smaller than 5 cm TL have a diverse diet but there is a decline in the importance of zooplankton, the preferred food item of small fish, as fish get larger. The shift in diet could be due to changes which have occurred in the lake. Water hyacinth, Eichhornia crassipes (Mart.) Solms, which harbours numerous insects in its root balls, now has extensively coverage over the lake. The native fish species which preyed on these insects (e.g. haplochromines) have largely been eliminated and O. niloticus could be filling niches previously occupied by these cichlids and non cichlid fishes. The change in diet could also be related to food availability and abundance where the fish is feeding on the most readily available food items.

Item Type: Book Section
Title: Changes in feeding biology of Nile tilapia, Oreochromis niloticus (L.), after invasion of water hyacinth, Eichhornia crassipes (Mart.) Solms, in Lake Victoria, Kenya
Personal Creator/Author:
CreatorsEmail
Njiru, M.
Title of Book: Report on Fourth FIDAWOG Workshop held at Kisumu, 16 to 20 August 1999
Series Name: LVFRP Technical Document
Number: 7
Page Range: pp. 175-183
Date: 1999
Publisher: Lake Victoria Fisheries Research Project
Place of Publication: Jinja, Uganda
Projects: Lake Victoria Fisheries Research Project Phase II
Issuing Agency: Lake Victoria Fisheries Organization
Additional Information: LVFRP/TECH/99/07
Uncontrolled Keywords: Africa; Kenya; Lake Victoria; Nile tilapia; water hyacinth; data collection
Subjects: Biology
Fisheries
Information Management
Item ID: 5006
Depositing User: Ms Maria Kalentsits
Date Deposited: 24 Mar 2011 10:27
Last Modified: 29 Sep 2011 15:34
URI: http://aquaticcommons.org/id/eprint/5006

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