Acoustic instrument calibration is fundamental to the quantitative use of its data for estimating aquatic resource abundance. Regular calibrations also allow instrument performance to be monitored to detect changes due to the environment or component dynamics, degradation, or failure.
The new report, CRR No. 326, is the second such report on the topic of acoustic instrument calibration. The first, CRR No. 144, was published during the era of analogue electronics more than a quarter of a century ago. Since then, not only has the acoustic equipment improved vastly with digital electronics and signal processing, but the techniques for applying them to studies of marine organisms have both advanced and diversified.
With technological innovation proceeding at an ever faster pace, the challenge to create a comprehensive and practical guide to calibrating acoustic instruments is formidable. This CRR documents the acoustic instruments currently used in fisheries research and surveys, the theoretical principles of calibrating these instruments, and the methods currently being practised for a selection of commonly used instruments.
The ICES Fisheries Acoustics, Science and Technology Working Group (WGFAST) motivates, facilitates and expedites developments in the field. It formed the Study Group on Calibration of Acoustic Instruments (SGCal), which authored the latest report.
The authors see this CRR as a valuable reference to both novice and experienced users of fishery acoustic instruments, but recognize that it is a provisional guide that requires refinement and update as the field continues to progress.
Launching an Autonomous Underwater Vehicle (AUV); photo - NOAA (National Ocean Service Image Gallery)