Fisheries Acoustics Theory and Practice

by Simmonds, John; MacLennan, David N.

• ISBN13: 9780632059942
• ISBN10: 063205994X
• Edition: 2nd
• Format: Hardcover
• Copyright: 2006-01-23
• Publisher: Wiley-Blackwell

Summary

The second edition of this important book provides thorough coverage of the subject with particular emphasis on practical acoustic methods for fish assessment. The authors, who are both widely experienced in the area, cover the underlying principles and current applications in fisheries research and outline the advantages and limitations of acoustic methods.This fully updated and revised edition contains much information on new techniques, equipment and their use. Fisheries Acoustics, 2nd edition, includes important information relating to practical problems of survey design, execution, and interpretation and is illustrated using examples drawn from acoustic surveys on commercially important fish species from many areas of the world.

Author Biography

John Simmonds is the Head of Pelagic Fisheries Research at the FRS Marine Laboratory, Aberdeen, UK

David MacLennan is a consultant in fisheries research and technology, and a former Deputy Director at the FRS Marine Laboratory

Table of Contents

Series Foreword	xi
Preface	xv
Acknowledgements	xvii
Introduction	1	(19)
A brief history	2	(4)
Synopsis	6	(3)
Acoustic terminology and symbols	9	(11)
Underwater Sound	20	(50)
Introduction	20	(1)
Sound waves	21	(5)
Pressure and displacement	22	(1)
Energy and intensity	23	(1)
Units	24	(1)
The decibel	24	(2)
Transducers and beams	26	(12)
The equivalent beam angle	32	(1)
Controlling the beam shape	33	(2)
End-fire transducer arrays	35	(1)
Limits to power transmission in water	35	(3)
Acoustic propagation	38	(9)
Beam spreading	38	(2)
Absorption	40	(2)
The sound speed	42	(4)
Pulses and ranging	46	(1)
Acoustic scattering	47	(14)
Targets large and small	48	(3)
Target strength	51	(2)
Standard targets	53	(3)
Target shape and orientation	56	(2)
Multiple targets	58	(1)
Volume/area scattering coefficients	59	(1)
Radiation pressure on targets	60	(1)
The inverse scattering problem	61	(1)
Echo detection	61	(4)
Reverberation	63	(1)
Noise	63	(2)
The operating frequency	65	(5)
Appendix 2A: Calculation of the acoustic absorption coefficient	67	(1)
Appendix 2B: Calculation of the speed of sound in water	68	(2)
Acoustic Instruments	70	(57)
Introduction	70	(1)
Echosounders	71	(8)
Scientific echosounders	74	(1)
The echo-integrator	74	(2)
The basic netsonde	76	(1)
The scanning netsonde	77	(2)
Instruments for measuring the target strength	79	(5)
The dual-beam echosounder	80	(2)
The split-beam echosounder	82	(2)
Resolution of single targets	84	(1)
Sonars	84	(14)
Searchlight sonar	85	(1)
Side-scan sonar	85	(3)
Sector scanners	88	(5)
Three-dimensional sonar systems	93	(4)
The Doppler effect	97	(1)
Wideband systems	98	(2)
Sound source location: pingers, transponders and hydrophone arrays	100	(2)
Installation of acoustic systems	102	(6)
Transducers on or near the vessel	102	(2)
Deep-towed bodies	104	(3)
Vessel noise performance	107	(1)
Calibration	108	(19)
The on-axis sensitivity	111	(2)
Experimental procedure	113	(5)
The TVG function	118	(1)
The equivalent beam angle	119	(1)
Overall sensitivity and the sound speed	120	(1)
Direction-sensing echosounders	121	(3)
Calibration of multi-beam sonars	124	(2)
Good calibration practice	126	(1)
Biological Acoustics	127	(36)
Introduction	127	(1)
Biological sounds	128	(1)
Hearing	129	(10)
Auditory detection capability	130	(3)
Masking and the critical bandwidth	133	(4)
Ultrasound and infrasound	137	(2)
Biological sonar	139	(6)
Environmental impacts	145	(13)
High-energy sound sources	145	(9)
Noise pollution	154	(3)
Limiting the damage	157	(1)
The swimbladder	158	(5)
Observation and Measurement of Fish	163	(54)
Introduction	163	(1)
Simple observation methods	164	(12)
Interpreting the echogram	164	(2)
Echosounder mapping	166	(5)
Side-scan sonar	171	(3)
Multi-beam sonar	174	(2)
Echo-counting	176	(11)
Single-target echoes	177	(3)
Range compensation	180	(1)
Single-beam echosounders	181	(3)
Direction-sensing echosounders	184	(1)
Thresholding and the sampled volume	185	(1)
Applications	186	(1)
Echo-integration	187	(16)
Range compensation	188	(1)
The echo-integrator equation	189	(2)
The linearity principle	191	(3)
Non-linear effects	194	(4)
Integration near the seabed	198	(3)
The threshold problem	201	(1)
Applications	202	(1)
Other techniques	203	(14)
Fixed sonar installations	203	(2)
Horizontal sonar for shallow water applications	205	(4)
Target tracking	209	(1)
Doppler sonar	210	(1)
Forward scattering	211	(1)
Appendix 5A: The true size distribution of fish schools	212	(3)
Appendix 5B: Calculation of the TVG error	215	(2)
Target Strength of Fish	217	(16)
Introduction	217	(1)
Target strength measurement techniques	218	(15)
Immobile fish	219	(1)
Live fish in cages	220	(5)
Wild fish	225	(4)
Modelling	229	(4)
Experimental results	233	(1)
Immobile fish	233