Effects of hydrological modification on fish habitability in riparian flood plain river basin

Abstract

Damming effect on demarcating fish habitability of some selected fishes in wetland based on image driven hydrological components like water presence frequency, water depth and hydro-period is the major focus of this present study. From the study, it is found that damming has hastened the rate of hydrological transformation increasing inconsistency in water presence frequency, reducing the depth of water and shortening hydro-period of the wetland. Integrated Rule Based Decision Tree (RBDT) modeling incorporating the above mentioned hydrological components has been used for finding out suitable habitat for some selected fishes (carp fishes, shrimp, tilapia and cat fishes) for both pre and post-dam periods. From these models, it is evident that a very small proportion of wetland area was suitable for good fish habitat (11.03% to 48.43%) during pre-dam period, however, post-dam hydrological alteration has almost deteriorated the good habitat area. Field investigation has proved that fish catch frequency, growth rate of fish were high earlier but it is significantly reduced during post-dam period. Such image driven hydrological component based fish habitat modeling is very new, however inclusion of more factors like water quality and food availability may enhance the quality of output.