Operation Manual
FarSounder, Inc.
F31552 (Rev. 2.6.1)
Page 46 of 56
Figure A.1. Echo sounder interference
Dolphins and porpoise are another source of interference similar to echosounders. When dolphins or
porpoise are near the vessel or playing in the bow wake, interference will often be present. This is from the
animals' own sonar systems pinging back at the FarSounder sonar. Though FarSounder's sonars operate
outside the hearing ranges of the great whales, dolphins and porpoises can hear the transmissions just
as they do those of echosounders. FarSounder has taken great care in ensuring that their sonars will not
cause any harm to any marine life. The duty cycles and transmit powers are significantly lower than those
of other marine acoustic systems that are commonly accepted throughout the world. In fact, FarSounder's
products have been reviewed by scientists at the National Marine Fisheries Service and been found to have
no negative impact on the marine environment
1
.
1
"NOAA's Ocean Acoustics Program (NMFS Office of Science and Technology) has assessed the technical specifications of the
current version of the FarSounder sonar technology and concurs that, based on the sound source level, signal duration, directionality,
and operational frequency band, there are no anticipated injurious effects on marine mammals or other marine species from it's
deployment." --Brandon Southall, NMFS
