Yūsuke

is a fisherman.

Background
His father died fighting the marlin, and later in his life determined to avenge his father's death.

Adventures at Sea Arc
When Aoba and Guy was beaten by a summoned marlin, he tried to beat it, only to be saved by Naruto. He said because of the summon, fishermen were scared to catch fish into the sea. He wanted to have a sturdier boat, internal combustion engine and a fishing rod which can defeat the marlin.

The next morning the four ninjas prepared those three, and went to the sea. He then successfully caught the marlin. He then waved goodbye to Naruto as they sail.