There is an island called "Fisherman Island" that you can access with a boat after you finish Squelch's Cave. Now you can go fishing! Check out the "Fish Trading Shop" for fishing line and bait.

We recommend selling your catch at this shop. Trading rates change day by day and sometimes they'll pay you twice the regular price!  But sometimes they will pay you less too... But don't get discouraged! Keep checking in and don't miss the chance to sell your catch for a great deal!