Haddock avoidance reactions during trawling
Original version
This report is not to be cited without prior reference to the authorsAbstract
Fish reaction to the whole trawling operation was studied using
a stationary echo sounder-system observing the fish in front of
the vessel and during trawl passage. Strong avoidance reactions
were observed on haddock, with both horizontal and
vertical movements of the fish. The observations indicate that
the fish density available for the bottom trawl at shallow
depths may be significantly higher than estimated by the echo
integration system on board the trawling vessel, and that
vessel avoidance may be an important trawl selection factor.