Green turtle and fish identification based on acoustic target strength

(1) Sunardi Sunardi Mail (Universitas Ahmad Dahlan, Indonesia)
(2) Azrul Mahfurdz Mail (Sultan Ahmad Shah Polytechnic, Malaysia)
(3) * Shoffan Saifullah Mail (Universitas Ahmad Dahlan, Indonesia)
*corresponding author


Fisherman accidentally caught sea turtles in their fishnet. It could be dangerous for its population. This study measures the turtle target strength (TS) using modified echosounder. The result could be used to improve the efficiency of turtle repellent device. The experiment conducted in a hatchery fiber tank contained saline water. The Green were 1, 3, 12 and 18 years old. This study used three species of fish, which serves to distinguish the value between fish and sea turtles. TS of the animals were calculated incorporating reference targets (sphere). The echo power of the turtle was compared with the solid steel sphere which is confirmed good agreements with the theoretical values. The echo power reference by applying Fast Fourier Transform (FFT) analysis has been used in calculating TS of the animal. The time domain of the echo evaluation in different angles shows the difference in the structure of the echo signal between the tortoise's body parts. This study reveals that high echo strength is acquired from the carapace and the plastron parts. The finding also showed that there are significant differences between 3, 12, 18 years old turtles and fish in every angle measurement.


Target strength (TS); Green turtle; Echo power; Fast fourier transform (FFT); Acoustic measurement



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[1] L. K. Jordan, J. W. Mandelman, D. M. McComb, S. V. Fordham, J. K. Carlson, and T. B. Werner, “Linking sensory biology and fisheries bycatch reduction in elasmobranch fishes: a review with new directions for research,” Conserv. Physiol., vol. 1, no. 1, p. cot002-cot002, Apr. 2013, doi:

[2] L. Bull, A review of methodologies for mitigating incidental catch of seabirds in New Zealand fisheries. Science & Technical Pub., Department of Conservation, 2007, available at:

[3] S. Løkkeborg, “Best practices to mitigate seabird bycatch in longline, trawl and gillnet fisheries—efficiency and practical applicability,” Mar. Ecol. Prog. Ser., vol. 435, pp. 285–303, Aug. 2011, doi:

[4] G. S. Stone, L. Cavagnaro, A. Hutt, S. Kraus, K. Baldwin, and J. Brown, “Reactions of Hector’s dolphins to acoustic gillnet pingers,” Conserv. Serv. Levy Contract Rep., vol. 3071, 2000, available at:

[5] T. M. Cox, A. J. Read, D. Swanner, K. Urian, and D. Waples, “Behavioral responses of bottlenose dolphins, Tursiops truncatus, to gillnets and acoustic alarms,” Biol. Conserv., vol. 115, no. 2, pp. 203–212, Feb. 2004, doi:

[6] M. Gazo, J. Gonzalvo, and A. Aguilar, “Pingers as deterrents of bottlenose dolphins interacting with trammel nets,” Fish. Res., vol. 92, no. 1, pp. 70–75, Jul. 2008, doi:

[7] P. Berggren, J. Carlström, and N. Tregenza, “Mitigation of small cetacean bycatch; evaluation of acoustic alarms (MISNET),” Rep Int Whal Comm SC/54/SM2, pp. 1–28, 2002.

[8] J. W. Valdemarsen and P. Suuronen, “19 Modifying Fishing Gear to Achieve Ecosystem Objectives,” Responsible Fish. Mar. Ecosyst., p. 321, 2003.

[9] E. Gilman et al., “Mitigating sea turtle by-catch in coastal passive net fisheries,” Fish Fish., vol. 11, no. 1, pp. 57–88, Mar. 2010, doi:

[10] R. L. Lewison, L. B. Crowder, and D. J. Shaver, “The Impact of Turtle Excluder Devices and Fisheries Closures on Loggerhead and Kemp’s Ridley Strandings in the Western Gulf of Mexico,” Conserv. Biol., vol. 17, no. 4, pp. 1089–1097, Aug. 2003, doi:

[11] S. P. Epperly, “Fisheries-Related Mortality and Turtle Excluder Devices (TEDs),” in The Biology of Sea Turtles, Volume II, P. L. Lutz, J. A. Musick, and J. Wyneken, Eds. New York, New York, USA: CRC Press, 2002, p. 339.

[12] B. J. Gallaway, J. G. Cole, J. M. Nance, R. A. Hart, and G. L. Graham, “Shrimp Loss Associated with Turtle Excluder Devices: Are the Historical Estimates Statistically Biased,” North Am. J. Fish. Manag., vol. 28, no. 1, pp. 203–211, Feb. 2008, doi:

[13] M. Lenhardt, “Sea turtle auditory behavior,” J. Acoust. Soc. Am., vol. 112, no. 5, pp. 2314–2314, Nov. 2002, doi:

[14] A. Yudhana, “Turtle Hearing Classification for Turtle Excluder Devices Design,” Universiti Teknologi Malaysia, 2011.

[15] D.-Z. Chu, “Technology evolution and advances in fisheries acoustics,” J. Mar. Sci. Technol., vol. 19, no. 3, pp. 245–252, 2011, available at:

[16] X. Lurton and S. DeRuiter, “Sound radiation of seafloor-mapping echosounders in the water column, in relation to the risks posed to marine mammals,” Int. Hydrogr. Rev., no. 6, 2011, available at:

[17] D. N. MacLennan and E. J. Simmonds, Fisheries acoustics, 1st ed., vol. 5. Springer Netherlands, 1992, available at:

[18] K. Abe, K. Sadayasu, K. Sawada, K. Ishii, and Y. Takao, “Precise target strength measurement and morphological observation of juvenile walleye pollock (Theragra chalcogramma),” in Oceans ’04 MTS/IEEE Techno-Ocean ’04 (IEEE Cat. No.04CH37600), 2004, vol. 1, pp. 370–374, doi:

[19] K. J. Benoit-Bird and W. W. L. Au, “Echo strength and density structure of Hawaiian mesopelagic boundary community patches,” J. Acoust. Soc. Am., vol. 114, no. 4, pp. 1888–1897, Oct. 2003, doi:

[20] J. Frouzova and J. Kubecka, “Changes of acoustic target strength during juvenile perch development,” Fish. Res., vol. 66, no. 2–3, pp. 355–361, Feb. 2004, doi:

[21] K. J. Benoit-Bird, W. W. L. Au, and C. D. Kelley, “Acoustic backscattering by Hawaiian lutjanid snappers. I. Target strength and swimbladder characteristics,” J. Acoust. Soc. Am., vol. 114, no. 5, p. 2757, 2003, doi:

[22] T. Stanton, “Review and recommendations for the modelling of acoustic scattering by fluid-like elongated zooplankton: euphausiids and copepods,” ICES J. Mar. Sci., vol. 57, no. 4, pp. 793–807, Aug. 2000, doi:

[23] K. Amakasu and M. Furusawa, “Effective frequency for acoustic survey of antarctic krill,” in Oceans ’04 MTS/IEEE Techno-Ocean ’04 (IEEE Cat. No.04CH37600), 2004, vol. 1, pp. 375–382, doi:

[24] K. G. Foote, “Importance of the swimbladder in acoustic scattering by fish: A comparison of gadoid and mackerel target strengths,” J. Acoust. Soc. Am., vol. 67, no. 6, pp. 2084–2089, Jun. 1980, doi:

[25] S. Sunardi, A. Yudhana, J. Din, and R. B. R. Hassan, “Swimbladder on fish target strength,” TELKOMNIKA (Telecommunication Comput. Electron. Control., vol. 6, no. 2, p. 139, Aug. 2008, doi:

[26] R. Jørgensen, “Acoustic target strength of capelin measured by single-target tracking in a controlled cage experiment,” ICES J. Mar. Sci., vol. 59, no. 5, pp. 1081–1085, Oct. 2002, doi:

[27] J. H. Miller and D. C. Potter, “Active high frequency phased-array sonar for whale shipstrike avoidance: target strength measurements,” in MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295), 2001, vol. 4, pp. 2104–2107, doi:

[28] K. J. Benoit-Bird and W. W. L. Au, “Prey dynamics affect foraging by a pelagic predator (Stenella longirostris) over a range of spatial and temporal scales,” Behav. Ecol. Sociobiol., vol. 53, no. 6, pp. 364–373, 2003, available at:

[29] T. K. Stanton, “On acoustic scattering by a shell-covered seafloor,” J. Acoust. Soc. Am., vol. 108, no. 2, pp. 551–555, Aug. 2000, doi:

[30] K. J. Benoit-Bird and W. W. L. Au, “Target strength measurements of Hawaiian mesopelagic boundary community animals,” J. Acoust. Soc. Am., vol. 110, no. 2, pp. 812–819, Aug. 2001, doi:

[31] T. Mukai, K. Iida, Y. Ando, H. Mikami, Y. Maki, and R. Matsukura, “Measurements of swimming angles, density, and sound speed of the krill euphausia pacifica for target strength estimation,” in Oceans ’04 MTS/IEEE Techno-Ocean ’04 (IEEE Cat. No.04CH37600), 2004, vol. 1, pp. 383–388, doi:

[32] J. D. Warren, T. K. Stanton, D. E. McGehee, and Dezhang Chu, “Effect of animal orientation on acoustic estimates of zooplankton properties,” IEEE J. Ocean. Eng., vol. 27, no. 1, pp. 130–138, 2002, doi:

[33] A. Drew, “Initial Results from a Portable Dual-Beam Sounder for In Situ Measurements of Target Strength of Fish,” in OCEANS ’80, 1980, pp. 376–380, doi:

[34] J. M. Jech, D. Chu, K. G. Foote, T. R. Hammar, and L. C. Huffnagle, “Calibrating two scientific echo sounders,” in Oceans 2003. Celebrating the Past ... Teaming Toward the Future (IEEE Cat. No.03CH37492), 2003, p. 1625–1629 Vol.3, doi:

[35] K. G. Foote and D. N. MacLennan, “Comparison of copper and tungsten carbide calibration spheres,” J. Acoust. Soc. Am., vol. 75, no. 2, pp. 612–616, Feb. 1984, doi:

[36] I. N. Arnaya, N. Sano, and K. IIDA, “Studies on Acoustic Target Strength of Squid: Ⅰ. Intensity and energy target strengths,” Bull. Fac. Fish. Hokkaido Univ., vol. 39, no. 3, pp. 187–200, 1988, available at:

[37] J. Simmonds and D. MacLennan, Eds., Fisheries Acoustics: Theory and Practice, 2005, doi:

[38] S. Sarangapani, J. H. Miller, G. R. Potty, D. B. Reeder, T. K. Stanton, and Dezhang Chu, “Measurements and modeling of the target strength of divers,” in Europe Oceans 2005, 2005, p. 952–956 Vol. 2, doi:

[39] D. N. MacLennan, “The Theory of Solid Spheres as Sonar Calibratlcm Targets,” Scott. Fish. Res. Rep, 1981, available at:

[40] R. P. Hodges, Underwater Acoustics: Analysis, Design and Performance of Sonar, 2010, doi:

[41] O. Nakken and K. Olsen, “Target strength measurements of fish,” Rapp. Procès-Verbaux des Réunions Cons. Int. pour l’Exploration la Mer, vol. 170, pp. 52–69, 1977, available at:

[42] J. Kalinowski, A. Dyka, and L. Kilian, “Target strength of krill,” Pol. Polar Res, vol. 1, no. 4, pp. 147–153, 1980, available at:

[43] R. J. Urick, Principles of underwater sound for engineers, 3rd ed. McGraw-Hill, 1983.

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