Diet composition of Oreochromis niloticus from selected impoundments of different states, with special focus on toxigenic cyanobacteria identified using molecular techniques

Abstract The diet of Oreochromis niloticus from hypereutrophic Lake Chivero and oligo-mesotrophic Lake Kariba was studied in 2017, with focus on the consumption of cyanobacteria. Water and fish were sampled to investigate the relationship between water quality and the diet of 131 fish using microscopy methods. Thirty-six fish were sampled in the second sampling phase to determine the presence of toxin producing cyanobacteria in their stomach contents using PCR methods. Lake Chivero had higher conductivity values, phosphates and total phosphorus levels while temperature and transparency were lower than those recorded in Lake Kariba. Lake Kariba recorded significantly higher water temperatures in June, October and December than Lake Chivero (p