troll2 [intransitive and transitive] American English
to try to remove something from a river, ocean etc by pulling a rope, line etc through the water:
Ships towing huge magnets trolled the ocean floor.
I would troll for fish from the rowboat.
to try to obtain something by searching, asking people etc [= trawl British English]
troll (something) for something
Stewart spent hours trolling the Web for information.