Trawl catch data from surveys is used towards stock assessments and ecological studies with the general assumption that the trawl efficiency is the same between hauls and between years. In 2012, trials conducted with the Deep Vision stereo camera system mounted in the Harstad survey trawl indicated that individuals were meshed prior to the codend, with high numbers of previously meshed individuals entering the codend at the surface during haul back. (Underwood et al, 2014).