Does Interspecific Competition with Introduced Oreochromis mossambicus Affect Home Range of Etroplus sp.?

Etroplus suratensis (Bloch) and Etroplus maculatus (Bloch), are indigenous cichlids found in Sri Lanka. Oreochromis mossambicus (Peters) was introduced to enhance inland fisheries. The aim of this study was to investigate the interactions of indigenous and exotic cichlids. The study included space use (home range) of E. maculatus, E. suratensis and Oreochromis mossambicus. Quantitative, data were collected during a period of one year from an inlet of the Batticaloa Lagoon, Sri Lanka. Data revealed that the home range used by O. mossambicus was larger than that of the two indigenous species. The highest habitat overlapping area occurred between E. suratensis and O. mossambicus. In conclusion, it could be said that the introduced species O. mossambicus can compete with indigenous species especially E. suratensis where there was a habitat overlap and further laboratory studies and population studies may provide concrete evidence to the impact of the introduced species, on the indigenous species.