On 2ch I see people saying 釣 a lot. It means fishing, but I don't understand. Does it mean a troll? Thanks.

I can't say whether or not the specific instances you saw it used were meant in that way, but, yes, it does have that "troll" meaning.

>>1
何単発質問スレ立ててんの？
バカじゃねぇの？

>3

何日本語で煽ってんの？
ほんとクズな

やっぱり外人釣りじゃね?

朝から出たな
凄腕釣り師め…

おまいやさしいな
謝んなくていいし
釣られちゃだめだ

まだ繋がらないんだが。釣り？

釣り？つながらないよ。

もうイヤだ〜〜〜ぁ！
誰かなんとかしてくれ！

OMGWTF