Biodiversity and Abundance of Fish and Plankton of Nguru Lake, Northeastern, Nigeria.

Abstract

Aspects of ecology and fisheries of Nguru lake were studied for a period of twelve months between May 2006 and April 2007.Nguru Lake, which is part of the Hadejia-Nguru wetlands is a natural lake, with an area of about 58,100 hectares and depth of between 1.5m to 8m. There is scarcity of information on the biodiversity of the lake .Therefore this work was aimed at determining the composition, abundance and distribution of phytoplankton, zooplankton, and fish of Nguru Lake. The phytoplankton of Nguru lake consists of twenty five species of algae from four divisions, namely Chlorophyta,Cyanophyta, Bacillariophyta and Dinophyta. Some algae such as Zygnema sp, Microcystis sp, Chlorella sp and Anabaena sp occur throughout the year, while others occur seasonally. All the phytoplankton studied showed significant seasonal and spatial variation (P<0.05).The zooplankton of Nguru lake is made up of four groups, Cladocera (41%), Copepoda (24%), Rotifera (27%) and Protozoa (18%).There is a total of 16 species, with Moina sp and Keratella sp dominating the fauna. The zooplankton showed significant seasonal and spatial variation (P<0.05). Twenty four species of fishes belonging to thirteen families were recorded.The family Cichlidae dominated the fishes with 64%.The families Claridae and Osteoglossidae constituted 6% each, while the family Malapteruridae was the least with only 0.17%.The mean weight of fish caught per day was 540.17kg, from three landing sites, with 14 fishermen operating averagely from each site.

Key Words: Biodiversity, Fish, Plankton, Ramsar site.