Role in Counterfeit Island:
The Ribica sits at the docks, most likely docked after a good day of fishing, shown by the net (on the ship) and crates (nearby the ship) full of fish. At some point, a piece of paper contained part of a picture of a gargoyle floated by and landed on the top of the Ribica's mast. Later though, your Poptropican finds the piece of paper.
Role in Cryptids Island:
The Ribica appears at the Loch Ness and can be seen occasionally on the lake, (through the viewer).