The Cursed Shores

The Cursed Shores was an island of the Second Sea west of Waveborne, split in two and strewn with wooden wreckage under an eerie purple haze, with bridges linking the halves and a tall lighthouse. It is now removed, and the wiki says Cursed Isle, in the First Sea, took its place. The residents were an Angler, an Inn Keeper and Brothers Hurk, Squib and Gleem.

It was built to be the hardest place to catch fish: the wiki lists Progress Speed reductions as steep as -66% even for common fish. You needed level 100 or higher to enter, and it suggests Blessed Song (+40% Progress Speed), Steady (+20%), Mystical (+45%), Resilient (+35%), Divine (+20%), Piercing (+15%), Chaotic, Herculean (0.2 control) or Controlled (0.15 control). Mystical, Piercing and Herculean need Exalted Relics, and Blessed Song needs a Song of the Deep.

The bestiary has 13 fish, from Blisterfish and Gloombiter at Common to the Exotic Dreaming Aberration and the Secret Abyssborn Monstrosity. The Great Dreamer Rod sold here for 500,000E$, though the wiki finds its passives and stats lacking. Oscar's Locker is entered from an opening in the northern waters.