Zooplankton composition and community structure in Lake Tiga, Kano, Nigeria

Zooplankton in Lake Tiga was identified and its community structure assessed between March 2009 and March 2011. A total of 54 species of zooplankton was recorded, comprising two species of Protozoa, 26 species of Rotifera, eight species of Copepoda, 11 species of Cladocera, four species of Ostracoda and three species of insect larvae. Species occurrence and abundance were both higher in the dry season than in the rainy season. Occurrence showed an increasing trend from the upper basin towards the lower basin (dam site) in the surface waters and a decreasing trend from the surface down to the bottom of the lake. Zooplankton abundance showed no definite pattern in its surface horizontal variation but showed a decreasing trend from the surface down to the bottom of the lake. In terms of species diversity, Rotifera had the highest number of zooplankton species, followed by Cladocera, Copepoda, Ostracoda, insect larvae and Protozoa. In terms of abundance, Rotifera again had the highest abundance value, followed by Cladocera, Copepoda, Protozoa, Ostracoda and insect larvae. Species diversity and evenness indices indicated that Lake Tiga, although not pristine, was not polluted.