Target strengths of krill at 136 and 20 kHz

Estimation of krill target strength was made by ensonification of encaged live krill and using trawling-acoustic method . Ensonification of encaged live krill. For aggregations with mean lengths in the range (45,50) mm the mean single-krill target strengths are in the range (-68, -69) dB at 136 kHz. For aggregations with mean lengths in the range (43,47)mm the mean single-krill target strengths are in the range (-71, -77) dB at 20 kHz.
Trawling-acoustic method. For aggregations with mean lengths in the range (47,50) mm the mean target strengths in the range ( -71, -75) dB at 20 kHz were obtained. At the same frequency for aggregations with mean lengths in the range (41,47) mm the mean single-krill target strengths are in the range (-76, -81) dB.