Lidar target-strength measurements on Northeast Atlantic mackerel (Scomber scombrus)

• Published in: ICES Journal of Marine Science
• Main Authors: Tenningen, Eirik, Churnside, James H., Slotte, Aril, Wilson, James J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2006
• Subjects: Northeast Atlantic
• Online Access: http://dx.doi.org/10.1016/j.icesjms.2005.11.018; http://academic.oup.com/icesjms/article-pdf/63/4/677/29124614/63-4-677.pdf

Abstract A linearly polarized green (532 nm) laser and a digital video camera were used to determine the reflectivity (R) and lidar (LIght Detection And Ranging) target strength (TS) of live mackerel by comparison with a standard calibration target. The measured reflectivity was 0.0141 ± 0.0005 when the receiver was copolarized with the laser and 0.0092 ± 0.0004 when the receiver was cross-polarized. The corresponding TS values were −42.66 ± 0.24 dB for the copolarized channel and −44.86 ± 0.23 dB for the cross-polarized channel. The depolarization ratio (depolarized return over total return) of 0.396 is very different from earlier measurements of sardine, suggesting that depolarization might be useful for species identification.