Fishing

137 of the 608 species in NOKEMON never set foot on land. You will not catch a single one of them by walking up and throwing a ball, no matter how many you carry. They surface in water, and water needs a rod.

The rod is not bought. You forge it: gather the metal, the wood and the coal, add the essence, and take it all to the Plaza forge. From then on any shoreline is a place you can work, and the ones below only show up for people who did that.

They cluster around The Shores, The Lake, Primordial Vale and Frostmere. Every one of them carries the same hard supply cap as the rest of the world, so the water runs out too.