Catch per unit effort (CPUE) and water level variations in the lower reaches of the White VoltaRiver (Yapei), Ghana

摘要

Catch per unit effort (CPUE) and water level variations in the lower reaches of the White Volta River were studied at three landing sites namely, Pataplapei (upstream), Porturto (midstream), and Aglassipei (downstream) from October 2011 to March 2012 to provide relevant information for further and future studies. The water depths were measured monthly with speedtech hand eco sounder. Fishing effort was measured as the number of fishermen per day whereas catch per unit effort (CPUE) was defined in this study as kilogram of fish per canoe per day (kg/canoe/day). Post flood season (October to December) had increasing CPUE associated with decreasing water levels. The dry season (January to March) however, had both fluctuating CPUE against the decreasing waters and decreasing CPUE associated with the decreasing water levels particularly in Pataplapei (upstream). Overall, the mean CPUE during the dry season was slightly higher (1.03 kg/canoe/day higher) than the post flood season whereas the fishing effort was higher in the post flood season than the dry season. Aglassipei (downstream) had mostly the highest mean CPUEs, followed by Pataplapei (upstream). Porturto (midstream) had mostly the lowest mean CPUEs due to the high fishing pressure at that site.?Moreover, total catches declined as the water levels drew down. The post flood season (October-December) had more catches than the dry season (January-March).