caa a22 4500 39755110X CHVBK 20180308164750.0 cr unu---uuuuu 161202e199604 xx s 000 0 eng 10.1006/jmsc.1996.0029 doi (NATIONALLICENCE)oxford-10.1006/jmsc.1996.0029 Depth dependence of target strength of live kokanee salmon in accordance with Boyle's law [Elektronische Daten] [Tohru Mukai, Kohji Iida] The target strength (TS) of fish varies with a number of factors, especially the presence or absence of a swimbladder. This study investigated the effect of the swimbladder on the TS of live kokanee (Oncorhynchus nerka) in relation to depth. Experiments were conducted at Lake Kuttara, Hokkaido, Japan, which is abundant with kokanee. Fish samples were caught with a fishing net. The live fish were suspended on the sound beam axis, and tilted from −50° (head-down aspect) to +50° (head-up aspect). The dorsal aspect TS functions were measured at 50 kHz. Measurements were performed when the fish were forced to change depth rapidly. The TS values were measured as a function of tilt angle and depth, and the maximum dorsal aspect TS (TSmax) values and the averaged dorsal aspect TS (TSavg) values were calculated and compared. TSavgvalues were calculated with respect to fish tilt-angle distribution, which was assumed to have a mean value of −5° and a standard deviation of 15°. Both TSmaxand TSavg decreased with depth in accordance with Boyle's law, i.e. a reduction rate of 6.7 dB per 10 atm was observed. © 1996 International Council for the Exploration of the Sea Regular Articles nationallicence Boyle's law nationallicence depth dependence nationallicence echosounder nationallicence kokanee salmon nationallicence swimbladder nationallicence target strength nationallicence Mukai Tohru Faculty of Fisheries, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido 041, Japan aut Iida Kohji Faculty of Fisheries, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido 041, Japan aut ICES Journal of Marine Science Oxford University Press 53/2(1996-04), 245-248 1054-3139 53:2<245 1996 53 icesjms https://doi.org/10.1006/jmsc.1996.0029 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1006/jmsc.1996.0029 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mukai Tohru Faculty of Fisheries, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido 041, Japan aut NATIONALLICENCE 700 1- Iida Kohji Faculty of Fisheries, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido 041, Japan aut NATIONALLICENCE 773 0- ICES Journal of Marine Science Oxford University Press 53/2(1996-04), 245-248 1054-3139 53:2<245 1996 53 icesjms Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford