Diversity of Introduced Species of Fishes in Penjalin Reservoir Central Java Indonesia

The decreased diversity of fish is partly due to the introduction of fish or foreign species into the waters. The impact of this entry is relatively vast, not only damaging the environment and genetic but also disturbing the indigenous species and spreading disease and parasites to the fish. This study aimed to analyze the fish diversity of introduced species and indigenous species captured in Penjalin Reservoir and the correlation between biodiversity and water quality. The method included a survey with five Stations of sampling. The present study caught 539 fish, consisted of seven families, ten breeds, and 11 species (six introduced and five indigenous). The diversity of introduced species was higher than that of the indigenous. The captured introduced fish were Oreochromis niloticus, Oreochromis sp, Oxyeletris marmorata, Clarias gariepinus, Cyprinus carpio, and Poecilia reticulata. The similarity index of fish diversity was almost equal across Stations. The O. marmorata species had the highest relative abundance and dominated Penjalin Reservoir. The diversity of introduced species was positively correlated with the parameters of depth, pH, and free CO2 in the center of the reservoir, while the Total Suspended Solid (TSS) of the indigenous species was in the inlet of the Garung river. The significance of the present research is to promote the conservation of fish resources and to maintain a balanced ecosystem, especially the existence of introduced species and indigenous species in the waters of Penjalin Reservoir.