Report of the Study Group on Baltic Acoustic Data

Russian and Latvian scientists carried out an acoustic survey aboard RN ,,AtlantNIRO" in Subdivisions 26 and 28 from 12 - 31 October 1997. The integration covered 16419 square nautical miles and the integrated track was 1280 nautical miles. The survey grid and position of the trawl hauls are shown in Figure 3.1.1. The hydroacoustic equipment used was S[MRAD EK-500 echosounder working at 38kHz and the echointegrator system B1-500. The working speed of the vessel was 8 knots, the trawling speed was 4 knots. The integration interval was I Nm. The equipment was calibrated against a standard copper sphere in the vicinity of the Baltiysk harbour in calm \Veather. The vessel has been set by means of 3 anchor lines. The calibration sphere was at the distance of 11,4 m from transducer surface. The integration and hauling were performed during the daytime. RN ,,AtlantNIRO" used the mid water trawl RTffM 70/300 with a vertical opening 28 - 32 m and bar length in the codend of 6,5 mm. Totally 60 sample hauls were made