Three schools of fish were investigated with 1/2-second 30 kHz continuous wave pulses from distances up to 1200 m. The echoes were analyzed to determine the frequency distribution of energy and this was interpreted as the results of Doppler shifts due to the motion of the fish. The accurate measurement of the direction and magnitude of the maximum Doppler shift relative to the transmission frequency provides an accurate track of a school of fish and its swimming speed profile. The direct measurement of the spread of echo energy in frequency provides information on schooling behaviour and fish size.
Doppler structure in echoes from schools of pelagic fish
Doppler-Struktur in den Echos von Hochsee-Fischschwaermen
Journal of the Acoustical Society of America ; 55 , 6 ; 1313-1322
1974
, 7 Quellen
Article (Journal)
English
AKUSTIK , SCHALLORTUNG , ECHOLOTUNG , DOPPLER-EFFEKT , ECHO
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