Diversity and abundance of Synodontis (Cuvier, 1816) species in the lower river Benue, Makurdi, Benue state, Nigeria

Abstract

The diversity and abundance of the Synodontis species in River Benue at Makurdi were studied over a 24 month period, from January 2009 to December 2010. A total of 1104 specimens, comprising 16 species were identified. The 16 species were: S.schall, 635 (57.52%); S.gambiensis,109 (9.87%); S.membranaceus,106 (9.60%); S.clarias, 93 (8.42%); S.omias, 51 (4.62%); S.melanopterus, 28 (2.54%); S.budgetti, 19 (1.72%); S.sorex, 12 (1.09%); S.nigrita, 11(1.00%); S.courteti, 9(0.82%); S.violaceus, 9(0.82%); S.resupinatus, 8(0.72%); S.filamentosus, 6(0.54%); S.batensoda, 3(0.27%); S.ocellifer, 3(0.27%) and S.vermiculatus, 2(0.18%). Out of the 1104 specimens, 594 (54.80%) were males, while 510 (46.20%) were females, with the male to female sex ratio of 1.2:1. The diversity indices also showed that S. schall had the highest diversity (Shannon Weiner H 6.40; Simpson 1-D 1.00; Brillouin 6.20 and Margalef 71.30). The least was recorded from S.vermiculatus (Shannon Weiner H 0.69; Simpson 1-D 0.52; Brillouin 0.60 and Margalef 209.23).