TY JOUR TI USING SONAR EQUIPMENT DURING THE PERIOD OF ICE FORMATION ON WATER BASINS KW winter period KW ice cover KW hydroacoustic survey KW ichthyologic research technique KW hydroacoustic complex JO Vestnik of Astrakhan State Technical University AU Aldokhin, A.. AU Chemagin, A.. PY 2018 IS 2018 PB Astrakhan State Technical University