Reactions of herring to trawling noise
Original version
This report is not to be cited without prior reference to the authorsAbstract
The reaction of herring during pelagic trawl sampling has been
studied by use of a high-frequency scanning sonar mounted on the
headline of the trawl. The difficulties of obtaining high catch
rates on shallow herring layers by single-vessel trawling are
demonstrated. Propeller-noise avoidance is suggested as the main
reason for the low fish density observed behind the trawling
vessel. Minor adjustments in trawling technique to improve catch
efficiency are suggested.