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Ohizumi H, Kuramochi T, Amano M, Miyazaki N. Prey switching of Dall’s porpoise Phocoenoides dalli with population decline of Japanese pilchard Sardinops melanostictus around Hokkaido, Japan. Mar Ecol Prog Ser. 2000;200: 265–275. Götz, T., Pacini, A. F., Nachtigall, P. E. & Janik, V. M. The startle reflex in echolocating odontocetes: Basic physiology and practical implications. J. Exp. Biol. 223, jeb208470 (2020).

Data were collected over a span of four years, from September 2012 to September 2016 where porpoises incidentally caught alive in pound nets upon their release were equipped with a high-resolution sound and movement recording tag with four silicone suction cups (DTAG 46; see www.soundtags.org). The tagging was approved and carried out in accordance to relevant guidelines and regulations by the Danish Welfare Division (Ministry of Justice, 2010-561-1801 and 2015-15-0201-00549) and carried out under the permission from the Danish Forest and Nature Agency (NST-3446-0016).

Discussion

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