Mon Calamari had no land. Just water. Sometimes the planet is called Dac by hippies who feel that calling the planet Mon Calamari margainalizes the Quarren.
Over the planet's history, the Mon Calamari and the Quarren fought many many wars with the Mon Calamari winning almost all of them. The Quarren were constantly getting their rights taken away and being forced to deeper waters. The Quarren Isolation League used the Clone Wars as an excuse to stir things up again, but the results didn't change. When the Empire came on the scene, they opened Mon Calamari to commercial fishing which outraged the Mon Calamari. After a few years of listening to their complaints, the Empire made them all slaves. This was the last straw, and the Mon Calamari did the unthinkable. They teamed up with the Quarren and forced the Empire out of town. Mon Calamari became important after that- assuming that you measure importance by how often it was invaded.