TrainingWe offer a one-week course in fisheries acoustics covering basic principles of sound propagation and reflection underwater, surveying equipment and density estimation (see course outline below) which can be given anywhere in the Southern African region. To date, two such courses have been given in Swakopmund, Namibia, to fisheries scientists and technicians from the region. Both included practical calibration exercises at sea on a local research vessel (below). The course can be tailored to your special needs to include, for example, survey design and error analysis, and to give greater emphasis on specialized topics such as the estimation of target strength and acoustic methods of target identification and classification. 

In addition, we offer practical hands-on training in fisheries acoustics during surveys and experimental cruises, with emphasis on one-on-one interaction. We are also able to assist and train researchers in the planning and design of surveys and associated experimental work, and in the processing of the data and the analysis and reporting of the results. 


FRS Acoustic Course: Outline


1. Introduction and basic principles of sound 2. Generation of sound – the transmitter
Introduction The transmitter
Basic principles of sound Choice of operating frequency
Echo-sounder considerations Pulse duration and receiver bandwidth considerations 
Decibel units Ping interval


3. Generation of sound – transducers 4. Propagation of sound underwater
Magnetostrictive transducers Attenuation
Ceramic transducers Refraction
Source level Reflection
Intensity and beam patterns  
Transducer bandwidth and Q factor   
Nearfield and farfield  
Directivity factor and directivity index  
The equivalent ideal beam angle  


5. Factors affecting target detectability 6. Echo-sounders, sonars and netsounders
Noise Echo-sounders
Sources of acoustic noise Sonars
Hydrodynamic noise Side-scan sonars
Machinery noise Net sounders
Ambient noise  
Reflection from other targets  
Noise reduction  


7. Introduction to fish target strength 8. Determination of fish target strength
Target strength Measurements on single dead or captive fish 
Fish size and target strength dependence Cage experiments 
The effects of fish tilt angle In-situ methods
  Single target detectors


9. Determination of fish density 10. Calibration
Echo integration theory The on-axis sensitivity
The area back-scattering coefficient The reciprocity technique 
Echo integrators The calibrated hydrophone 
  The standard sphere method
  The TVG function
  The equivalent beam angle

Practical work sessions to introduce participants to:

1. General Operation Of SIMRAD Echo Sounders 2. Echo Integration Analysis Software
What you should touch  
What you shouldn’t touch