Well come from Bangladesh.

Old technology ! they have been using mid water trawsl with planing trawl doors on the great lakes since the 1960s The also run a depthsounder on the mouth of the trawl so they know hoe far the net is off the bottom and can adjust the trawl up and down with ease Besides chasing fish lots of places with rocks as big as houses if the trawl ever went to the bottom you would never get it back