Seasonal distribution of zooplankton in the northern basin of Lake Chad

More than 300 pairs of fine and coarse mesh plankton net samples were collected in the northern basin of Lake Chad during an 18-month period, June 1967 to November 1968. The seasonal distribution and abundance of the dominant species of Rotifera and Crustacea are given in addition to a general description of the hydrology and circulation of the northern basin of the lake. The composition and abundance of the zooplankton varied considerably over the sampling period; a generalized seasonal cycle is suggested. Synoptic estimates of absolute abundance are presented and compared to those in the southeastern portion of the lake.