Heterogeneity habitat of three threatened freshwater catfishes

different rivers were water flow and depth which showed conformity with Gorman

and Karr (1978), Angremeier and Schlosser (1989), Copp et al. (1994), Garner

(1996) and Sarkar and Bain (2007). The habitat preference of endangered O. pabda

with slower and deeper water in all the studied rivers was also observed in other

fishes by Lamouroux et al. (1999), Lamouroux and Souchon (2002) and Carter et

al. (2004). Sarkar and Bain (2007) reported the habitat preference towards slow

water current in some Cyprinids.

Besides from velocity and depth, the physicochemical variables conductivity, pH

and temperature have been found to be significant variables in structuring sites and

assemblage of the three Silurids ( O. pabda, O. pabo and O. bimaculatus ) in the

tropical rivers under study of India. In the present study, O. pabo associated with

conductivity in abundance showed the available favorable conditions for these

species. Taylor et al. (1993) and Wilkie and Wood (1981) are reported conductivity

to be the most important variables in structuring fish assemblages at local spatial

scales across a broad region. The employed forward selection procedures of the

CCA make it possible to identify those environmental variables, which influenced

the abundance of three Ompok species.

The study is the first of its kind in the tropical rivers of India which identified

significant, comprehensive dataset where depth and flow are identified as a major

component of that structure. The water depth and flow are found to be the most

important habitat variable in shaping fish distributions for Silurids in India (Bain

and Knight, 1996; Arunachalam, 2000; Sarkar and Bain, 2007). The present study

generated new information on priority habitat use of three threatened Silurid fishes

which will provide specific guidance on channel habitats with inclusive ranges

of depths, substrate and current velocities needed to support the threatened fish

species therefore to include in conservation planning. Furthermore, our results

suggests that the importance of environmental influences on the threatened fishes

can be used to guide protection and management activities and support restoration

efforts of relatively unaltered fish habitat. Conservation measures should be

planned keeping in view the habitat requirements and associated relationship with

the fish assemblage at local scale.

Acknowledgements

The authors are thankful to Director, National Bureau of Fish Genetic Resources

(NBFGR), Lucknow for financial support and laboratory facility.

References

Angermeier PL, Schlosser IJ. 1989. Species-area relationships for stream fishes. Ecology.

70 : 1450-1462.

International Journal of Bioinformatics and Biological Sciences : v.2 n.3&4. Dec. 2014

141