Target strength of the common jellyfish (Aurelia aurita): A preliminary experimental study with a dual-beam acoustic system


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Mutlu E.

ICES JOURNAL OF MARINE SCIENCE, cilt.53, sa.2, ss.309-311, 1996 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 53 Konu: 2
  • Basım Tarihi: 1996
  • Doi Numarası: 10.1006/jmsc.1996.0040
  • Dergi Adı: ICES JOURNAL OF MARINE SCIENCE
  • Sayfa Sayıları: ss.309-311

Özet

An enclosure was designed for experiments estimating the target strength (TS) of the common jellyfish (Aurelia aurita) in the Black Sea. A BioSonics echosounder (Model 102) equipped with 120 and 200 kHz dual-beam transducers was used for the measurements. The average acoustic cross-section for each size class was used in functional regression equations to relate the mean TS (dB) of jellyfish to its disc diameter d (cm) and wet weight W (g). These were found to be as follows: TS = 14.72 log d - 74.63 and TS = 5.71 log W - 69.41 at 120 kHz; TS = 39.65 log d - 104.38 and TS = 14.53 log W - 88.07 at 200 kHz. The TS values were found to fluctuate periodically with time. The results showed a variation of - 54 to - 67 dB at 120 kHz for 15.5 cm diameter individuals, with a period of 7.5 to 10 sec; and a variation of -58 to -68 dB for 11.5 cm individuals at 200 kHz, with a period of 6 to 12.5 sec. (C) 1996 International Council for the Exploration of the Sea