Diel variation in fish species composition in agbura river, a tributary of the lower nun river, Niger-Delta, Nigeria

Abstract

The diel variation in the composition of fish species in Agbura River, a tributary of the lower Nun River was investigated. Fish samples were collected between April 2012 and March 2013   during day and night. Fish sampling was conducted monthly in three different stations of the river. Out of the 1,137 fish samples, a total of 677 (59.54%) and 460 (40.46%) individuals were caught during the day and night respectively. Of the 29 species, 9 were restricted to daytime catch only, while only 3 species were restricted to night catch. The remaining 17 species occurred during both day and night. The dominant daytime catch was Synodontis budgetti and Synodontis batensoda, while the dominant night catch included Bagrus bayad macropterus. The results of the study showed that the diel variations in fish species composition in Agbura River were related to the activity pattern of the fish during different times, as more fish were caught when active. This was discussed and compared with the findings of earlier studies conducted in different water bodies in the Niger Delta and elsewhere