Underwater wireless channel is severely affected by issues like multi path and fading. Signal to Noise Ratio (SNR) in UWSN is computed using passive sonar equation  given below: (1)SNR=SL−TL−NL+DI where SL is source level of the target or noise generated by the target, TL is transmission loss in aquatic environment, NL is noise loss and DI is directive index. DI is the capability of receiving sensor to direct its antenna to avoid unwanted noise. SNR value must be greater than detection threshold (DT). All the above quantities are measured in dBreμPa. Transmission loss is given in following:(2)TL=10log(d)+α×d×10−3