I dunno if it even is because isn't that spelt trawling?
just looked it up and they're both correct fishing terms sigh
Trolling is typically done on lakes with fishing lines cast from the back of a boat. A trolling motor sets the boat speed. Trawling usually takes place at sea, with larger boats and wide nets.
Trawling is done by dragging nets along the seabed causing massive damage with huge inefficient polluting fuel-guzzling 1000 horsepower diesel engines.
Trolling is as the other guy says where you putter along with minimum effort and a tiny engine pulling a couple of baited lines through the water, seeing if you pass through a patch where anyone bites.
Trawling is far more analogous to the AI scrapers, hammering the absolute shit out of the ecosystem and throwing almost everything they scoop up away with no regard for the consequences.