Soil and water pH values also show correlation with the crab community structure. Low- pH conditions can be detrimental to crabs because they depend on calcium carbonate formation for exoskeleton and shell building. Low-pH values can cause exterior exoskeleton and shell erosion in crustraceans and hence they tend to avoid such places . Soil pH values in the upper zone of Kadolkele mangrove varied from 4.1 to 4.4 while it ranged between 5 and 6 in the lower zone. M. thukuhar and the juveniles of unidentified of all crab species were found to be high in the lower area where soil pH value is higher soil pH levels. This is in agreement whith the fidings of Plaziat. S. guttatum and S. smithii have shown positive correlation with soil pH in the Kadolkele mangrove.