AimFreshwater ecosystems are most threatened across the world due to anthropogenic factors. However, terrestrial biodiversity continues to receive significant conservation attention relative to freshwater biodiversity due to its charismatic species. Perhaps due to this, there are far fewer studies focusing on riverine biodiversity when compared with studies on terrestrial systems
MethodsThe study was conducted from December 2011 to January 2012 covering winter and summer seasons. Based on river characteristics, habitats were identified as pool, run and riffle. A segment of 100-150 m was considered as a sampling unit. Fish sampling was conducted by using dragnets (4’ x 12’) across all the habitats. Sampling effort of ten dragnets for approximately 120 minutes was spent per habitat. Data analysis was done using BiodiversityR software.
ResultsOverall, fish species richness was higher in the Tunga river basin (32 species) than in the Bhadra river basin (27 species). Species accumulation curve reached its asymptote across two river basins in the winter but not in the summer. Among all the fishes, Devario malbaricus was the most dominant species followed by Salmophasia boopis
ConservationThis study shows that habitat rich sites are also species rich. Fishes were dominant in mid stream orders as compared to higher orders in both the river basins. Also, the insectivorous guild (Devario malbaricus, Salmophasia boopis & Barilius bakeri) seems to be dominant across all the sampled habitats. Insectivorous guild was 0.86% in Tunga and 0.78% in the Bhadra river basin.