Subject: Infrasound and Fish Avoidance

From: Roger Campana <[email-masked]>
Date: Mon, 01 Jul 1996 14:01:46 -0700

Simrad Infrasound System:
Infrasound Sensor
The Infrasound Sensor is a tool capable of measuring the performance of any 
infrasound source.  Using an Inertial Measurement Unit (IMU) placed inside a 
neutrally buoyant sphere, the Infrasound Sensor System measures the 
acceleration in the water column generated by a infrasound source.  The 
acceleration data is captured by Simrad data acquisition software and logged 
on a PC.  Auxiliary sensors can also be attached and logged to the same PC 
file allowing the researcher to gather additional data regarding the 
performance of the infrasound source as well as the surrounding environment. 
 The logged data is then processed via Simrad post processing software. The 
result is a numerical and graphic display of the infrasound source 
performance.

Infrasound Source
The Infrasound Source is a device which produces low frequency sound under 30 
Hz, by creating an accelerated field of water particles in the water column. 
  In the laboratory studies at the University in Oslo it was demonstrated 
when water acceleration was at a rate of 0.01m/sec^2 an avoidance response 
was observed in salmonids.   Therefore the infrasound source creates an 
environment which fish avoid.

Simrad’s infrasound source is a prototype created by the University in Oslo. 
 The source, referred to as fish fence, has been tested by Simrad under 
contact to Battelle Pacific Northwest Laboratories.  The source showed 
promising results, therefore more tests on fish behavior are being performed.

Simrad has created two options to our customers for the development of an 
infrasound source.   The first option is to produce a source similar to the 
University in Oslo’s prototype.  This option is suited for research 
applications where the duty cycle of the source is switched on for short 
periods.  The second option is for a source which can be installed in the 
field to deter fish ingress continuously for a period of up to 90 days.

For further information or just to chat, contact either:
Jeff Condiotty , Marketing Manager Fisheries Research Products or
Roger Campana, Senior Design Engineer
Simrad, Inc.
1-800-426-5565
Lynnwood, WA USA