A Microprocessor Based Echo Integration System for Fisheries Research

Acoustic techniques are now widely used in fisheries research and management. One method used to estimate the total biomass in a specific area is the integration of echo sounder signals. A portable, microprocessor-based digital echo integrator has been developed that greatly simplifies real-time analysis of echo sounder data. Up to 30 depth intervals may be entered, along with TVG correction factors. Bottom tracking prevents the integration of bottom signals, and an operator-selected threshold reduces noise sensitivity. Constants may be entered to compensate for unique system parameters (source level, beam pattern, etc.). A bottom- locked mode of operation is also possible. The system is also designed to operate as a data logger with two channel capability. Raw data are digitized at a 7.45 kHz data rate for storage on digital magnetic tape. This system should be very useful in fisheries or oceanographic problems which require "real-time" data analysis.