The cast net fishery, Kainji Lake, Nigeria 1970-1997

Seisay, M.D.B. (1998) The cast net fishery, Kainji Lake, Nigeria 1970-1997. New Bussa, Nigeria, Nigerian-German (GTZ) Kainji Lake Fisheries Promotion Project, (Nigerian-German Kainji Lake Fisheries Promotion Project Technical Report Series, 12) (ISBN: 978-037-011-0; ISSN:1119-1449).

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Abstract

This study was carried out to establish trends in the cast net fishery of Kainji Lake, Nigeria. The cast net fishery was second in importance to the gillnet fishery in the early years after impoundment of the lake and still continues to be an important component of the fishery. Some of the economically important species such as Citharinus spp, Tilapia spp, Labeo spp, Alestes spp and Synodontis spp are exploited by cast nets. The study has not revealed any drastic perturbation in the species diversity, catch composition, and any real ecosystem overfishing. On the other hand, both the catfish, Auchenoglanis spp and the predator Hydrocynus spp appear to have increased in the catch in recent years. Never-the-less there is a decline in the mean weight of the major exploited fish species due to the capture of under sized fishes without allowing them to grow to 'legally' marketable sizes. The use of small meshed cast net and also fishing in the shallow waters of the lake can give rise to this situation. Thus, there are signs of growth overfishing in the fish stocks. It must also be acknowledged that the situation is complicated by the fact that in a multi-gear fishery as on Kainji Lake, the cast net fishery could not be managed in isolation without due regard to the other competing gears. The catch per unit of effort (CPUE) has declined in the cast net fishery possibly due to the increase in effort by the major fishing gears over the years. The ongoing extension campaigns by the KLFPP appears to be having the desired effect, as there was reduction in the number of the major fishing gears on the Lake in 1997. It can be anticipated that if this trend continues, the CPUE will recover in the long run. Yields observed from the mesh selectivity study revealed that for major species in the cast net fishery, both by number and weight, were maximal at 2.5 inch mesh, which contrasts with the fact that current minimum allowable mesh in the Fisheries Edict for the Lake is 2.0 inch. The adoption of 2.5 inch as the minimum allowable mesh in the cast net fishery is recommended to be included in future revision of existing regulations. It is also recommended that for this control to have a desired effect, the casting of the net from the shore should be prohibited so as to reduce the incidence of juvenile mortality in the nursery areas. (PDF contains 28 pages)

Item Type: Monograph or Serial Issue
Title: The cast net fishery, Kainji Lake, Nigeria 1970-1997
Personal Creator/Author:
CreatorsEmail
Seisay, M.D.B.
Series Name: Nigerian-German Kainji Lake Fisheries Promotion Project Technical Report Series
Number: 12
Date: 1998
Publisher: Nigerian-German (GTZ) Kainji Lake Fisheries Promotion Project
Place of Publication: New Bussa, Nigeria
Projects: Nigerian-German (GTZ) Kainji Lake Fisheries Promotion Project
Issuing Agency: Deutsche Gesellschaft für Technische Zusammenarbeit (Nigeria Office)
Uncontrolled Keywords: Nigeria, Lake Kainji; cast nets; catch/effort; fishery data; fishery management; lake fisheries; mesh regulations
Subjects: Management
Fisheries
Biology
Item ID: 3847
Depositing User: Ms Maria Kalentsits
Date Deposited: 11 Aug 2010 10:06
Last Modified: 29 Sep 2011 16:45
URI: http://aquaticcommons.org/id/eprint/3847

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