ICES Journal of Marine Science, 53: 297–302. 1996 Lateral target strength of Antarctic krill

• Main Authors: Roger P. Hewitt, David A. Demer
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Key words; acoustic target strength; Antarctic krill; Euphausia superba; Antarctic; Antarc*; Antarctic Krill
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.522.4208; http://swfsc.noaa.gov/uploadedfiles/operating_units/frd/survey_technology/lateral target strength of antarctic krill.pdf

An area of high krill (Euphausia superba Dana) density was continuously monitored with down-looking and side-looking sonars over a period of 24 h. Measurements of volume backscattering strength were used to describe the density of krill with depth and the vertical movement of krill over time. In situmeasurements were made of dorsal aspect target strength (TS) and, as krill moved into the near-surface layer (0–15 m), in situ measurements were made of lateral-aspect TS. The probability density function (PDF) of TS measurements made with the down-looking transducer had a mode at approximately "73 dB. The PDF of TS measurements made with the side-looking transducer was broader with a mode at approximately "67 dB. Sampled krill had a bi-modal length distribution with a major mode at 44 mm and a minor mode at approximately 30 mm.