Design Characteristics and Fish Catch Composition of Gillnets in the Upper Nun River, Bayelsa State, Nigeria
2023
T. E., Binyotubo, T. E., | T., Kingdom, T. | J. F., Alfred-Ockiya, J. F.
A survey of the design characteristics and fish catch composition of gill nets fishery in the Upper Nun River, Bayelsa, Nigeria was studied in three major fishing communities (Tombia, Polaku and Sabagriea). Types of netting materials, twine sizes, mesh sizes were determined, while the number, weights and dimensions of sinkers and their differences were noted. Fish samples caught with the various gill nets were collected twice in a month for six months. The fish were identified to species level. The results showed that there were three different categories of gill nets observed in the study area, viz; surface drift nets, mid-water drift nets and bottom set nets. Furthermore, it was observed that the three - panel gill nets (Trammel nets) were used only in Sabagriea, whereas one - panel nets were used in Polaku and Tombia. The gill net materials used in the study area were Polyamide for head and foot rope, and twine were used for mounting. The head rope length ranged from 50 – 200 m and depth were from 2.5 – 7.0 m. Mesh size were between 63.5 –152.0 mm, while cutting rate was all point cut and the twist direction Z. A total of 37 fish species belonging to 13 families were recorded with Mochokidae as the most abundant family. Osteoglossidae family was the least abundant, while Citharinus citharus were the most abundant (8.2%) species throughout the study period. The study recommends that the use of gill net of mesh sizes smaller than the recommended 76 mm should be discouraged.
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