ISSN 2375-0715
African Journal of Fisheries Science ISSN 2375-0715 Vol. 12 (7), pp. 001-007, July, 2024. Available online at www.internationalscholarsjournals.org © International Scholars Journals
Full Length Research Paper
Exploring the Dynamics of Gillnet Fishing in the Lower Nun River: A Study of Selectivity, Seasonal, Tidal, and Photoperiod Effects
Martin E. Allison1* and Daniel Okadi2
1Department of Fisheries and Livestock Production, Niger Delta University, Wilberforce Island P. M. B. 017 Yenagoa,
Bayelsa State, Nigeria.
2Department of Fisheries and Aquatic Environment, Rivers State University of Science and Technology, Port Harcourt,
Rivers State, Nigeria.
Accepted 21 December, 2023
Abstract
The fish species of the lower Nun River was sampled to determine gillnet selectivity and the effect of season, tide and photoperiod variation on the catch. A total of 11,156 specimens were caught belonging to 14 families consisting of 25 species. Gillnet selectivity was observed with a declining trend from the largest mesh size net of 15 mm (58%) in number and 59% by weight, 12 mm (33%) in number and 33% by weight with the least catch of about 9% by number and 8% by weight from the smallest (8 mm) net. In terms of seasonal variation, the rainy season catches were significantly higher (P< 0.05) than the dry season with relative abundance of 67 and 32% respectively. Tidal variation in the catches showed that catches were higher during the low tidal period (61%) than the high tide (39%). Significant photoperiod differences (P < 0.05) were observed with higher catches by day (58%) than by night.
Key words: Gillnet selectivity, seasonal, tidal, photoperiod, variation, Nun River.