To troll means to fish. In fact, looking up the definition of "trawl," it means "to troll"
Took me a while to figure out the humour inherent in the double meaning when I first came across it (in the 90s)
e.g., you might trawl for prawns but troll for snook.
I just assumed that with an american accent the words sounded the same so people stopped using 'trawl'... I've been wrong before though.