Determining sediment composition of coarse riverbeds using multi-beam echo-sounder backscatter and bathymetric features

2012 ◽  
Author(s):  
Dimitrios Eleftherakis ◽  
M. Snellen ◽  
AliReza Amiri-Simkooei ◽  
Dick G. Simons
2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Henry M. Manik

A preliminary research programme was carried out in order to study the acoustic wave reflection or target strength (TS) of tuna fish using a quantitative echo sounder (QES). The relationships between TS to fork length (FL) and swimbladder volume, for bigeye tuna (Thunnus obesus) and yellowfin tuna (T. albacares) are investigated. The TS of bigeye tuna was about 3 dB higher than yellowfin tuna when comparing species at the same size. The result can be correlated to the swimbladder volume differencebetween species. The relationship between TS and swimbladder volume was quantified for both species.Keywords: tuna fish, target strength, quantitative echo sounder


2016 ◽  
Author(s):  
Ross P. Anderson ◽  
◽  
Nicholas J. Tosca ◽  
Robert R. Gaines ◽  
Derek E.G. Briggs

2019 ◽  
Author(s):  
Landon Williamson ◽  
◽  
Nicolas Perdrial ◽  
John M. Hughes ◽  
Mae Kate Campbell ◽  
...  

Author(s):  
Xiankun Wang ◽  
Fanlin Yang ◽  
Hande Zhang ◽  
Dianpeng Su ◽  
Zhiliang Wang ◽  
...  

2017 ◽  
Vol 74 (5) ◽  
pp. 716-726 ◽  
Author(s):  
Nicola Quick ◽  
Lindesay Scott-Hayward ◽  
Dina Sadykova ◽  
Doug Nowacek ◽  
Andrew Read

Active echo sounding devices are often employed for commercial or scientific purposes in the foraging habitats of marine mammals. We conducted an experiment off Cape Hatteras, North Carolina, USA, to assess whether the behavior of short-finned pilot whales (Globicephala macrorhynchus) changed when exposed to an EK60 scientific echo sounder. We attached digital acoustic recording tags (DTAGs) to nine individuals, five of which were exposed. A hidden Markov model to characterize diving states with and without exposure provided no evidence for a change in foraging behavior. However, generalized estimating equations to model changes in heading variance over the entire tag record under all experimental conditions showed a consistent increase in heading variance during exposure over all values of depth and pitch. This suggests that regardless of behavioral state, the whales changed their heading more frequently when the echo sounder was active. This response could represent increased vigilance in which whales maintained awareness of echo sounder location by increasing their heading variance and provides the first quantitative analysis on reactions of cetaceans to a scientific echo sounder.


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